1 10 4 https://apconf-much.org/proceedings/files/original/0857e6282ee61d068bb9b965c0cbb292.pdf 2270caf0aebf9aceea4ea4b0d8b92db1 PDF Text Text Study on Corrosion Factors of Iron Artifacts Recovered from the Middle West Sea Kim Taek-joon¹, Yoo Dae-young² and Lee Hyeon-ji² ¹Curator, Natural Research Institute of Maritime Cultural Heritage ²Reseacher, National Research Institute of Maritime Cultural Heritage ABSTRACT This study investigates corrosion process through analysis of corrosion products and desalination solution as a precedent study to present proper conservation treatment methods for iron artifacts collected from the middle West Sea. Depending on the environment where the iron artifacts were buried underwater, the corrosion patterns may be different. In order to treat the heritage stably and effectively for conservation, the major corrosion factors and information to remove or control the factors should be obtained. The underwater environment is rich in water, oxygen and salt, and it is very easy for iron artifacts to be corroded. In an environment where oxygen supply is little like seabed mud, anaerobic corrosion may occur. The iron artifacts in the seabed may be deeply buried in the mud or exposed on the surface of the seabed. This study intends to obtain information on the corrosion pattern of iron artifacts collected from the seabed surface of middle West Sea. In addition to those deeply buried in dense silt, there are also cases of recovering those exposed on the seabed or shallowly buried in the surface layer. In this study, we obtained information on the corrosion patterns of iron artifacts recovered from the seabed layer in the central West Sea.The samples used in the study were corrosion products from iron artifacts excavated from waters of Mado, Taean and of Seomeopbeol, Ongjin and desalination solution and the major components of corrosion products and anions of desalination solution were analyzed using Scanning Electron Microscope-Energy Dispersive Spectroscope (SEM-EDS) and X-ray Diffraction (XRD), Ion Chromatography (IC). The analysis result shows that major components including P, S and Mackiwanite (FeS) were identified as compounds related to it. In the desalination solution, high concentration of Cl- and SO42- was measured. It is expected that this study result can be utilized as essential data for establishing methods for effective and systematic conservation of iron artifacts excavated from underwater and it is intended to continue additional studies such as analysis on corrosion product of iron artifacts recovered from various waters and corrosion reproduction experiment through collaboration with various fields. Keywords: middle West Sea, iron artifacts, corrosion factor, corrosion product List of Tabless Table 1. Results of analysis on corrosion product of iron pot recovered from Mado (EDS, XRD) Table 2. Results of analysis of corrosion product of iron pot recovered from Seomeopbeol sea area (EDS, XRD) Table 3. Results of analyzing desalination solution of iron pot excavated from Mado (IC) Table 4. Results of analyzing desalination solution of iron pot excavated from Seomeopbeol (IC) INTRODUCTION Middle West Sea is a place where underwater cultural heritage is buried. Along the Taean coast Goryeo celadon was net-caught while fishing octopus by Ongjingun Seomeopbeol, Ansansi Daebudo and Hwaseongsi Jebudo in Korea. In particular, five shipwrecks from Goreyo and Joseon dynasties were discovered and surveyed in the Taean offshore of Chungcheongnam-do for eight years from 2007 to 2015 and historic ships from early and mid-eighth century was discovered in the waters of Seomeopbeol in Incheon in 2013. Iron pots, which were used as kitchenware by crew or carried as cargo, were lifted. Underwater environment is rich in water, oxygen and salt where iron artifacts are easily corroded. In addition, in an environment where oxygen supply is low like in the mud, anaerobic corrosion may occur by sulfate reducing bacteria. Therefore, the corrosion patterns of iron artifacts may be different in the underwater environment depending on each condition or various factors. In order to conserve damaged iron artifacts effectively and stably, information on how to remove or control major factors that influence corrosion should be obtained. 1 �CORROSION OF IRON ARTIFACTS IN UNDERWATER ENVIRONMENT Cl- and SO42- are dissolved in seawater at about 19 gr and 2.6 gr per 1 L (1 gr = 0.0684 g), and their high electrical conductivity promotes corrosion of iron artifacts (Baek Young-Nam and Yeo Woon-Hwan 1980, 673). Deposits formed on the surface of iron artifacts are removed by the high flow rate of the environment, and corrosion can be accelerated (Japanese Standards Association 1984, 33). Due to these various factors, iron artifacts are actively corroded in the seabed environment, concretion, a very hard foreign substance is formed on the surface. According to previous studies, the main component of concretion is CaCO3, and iron artifacts are corroded and it is the clump of organisms and shells and surrounding mud. Concretion is densely formed and corrods independently from the external environment and the process is as follows (North and MacLeod 1987, 76-78): 1. Reduction reaction occurs with the formation of cathode in an isolated water in the concretion. 2. An anode is formed on the surface of iron artifacts, releasing Fe2+ and Fe3+ with oxidation reaction, resulting in creation of acidic solution at pH 4-5. 3. Hydrolysis of Fe2+ + H2O → Fe (OH)+ + H+ by acidic solution. 4. FeCO3 is formed as part of Ca2+ in CaCO3 of concretion is interchanged with Fe2+. 5. Part of CaCO3 is dissolved by Ca (HCO3)2 that includes H+, increasing pH concentration of the surrounding environment. 6. As the pH concentration rises, oxides, hydroxides and hydroxide chlorides such as Fe2+and Fe3+ are gradually eluted. 7. During steps one to six, CaCO3 condensate is gradually dissolved and hard iron cementing is formed. In addition, anaerobic corrosion can occur in places where oxygen is scarce, such as deep in the mud of the seabed environment. The typical example of anaerobic corrosion of iron artifacts is corrosion by sulfide reduced by sulfate reducing bacteria (4Fe + SO42-+ H+→ 3Fe2++FeS + H2O). The resulting corrosion forms black iron sulfide, which is oxidized in red when exposed to the atmosphere (Fujii 2009, 50-51). METHODOLOGY In this study, desalination solution (Sodium Sesquicarbonate 0.1M aqueous solution) used during the conservation treatment of iron pots collected from Mado, Taean, Chungcheongnamdo and waters of Seomeopbeol, Ongjin, Incheon and corrosion products removed from the surface, were used as samples. The iron pots from the Mado were discovered through visual exploration of the sea bottom and part of the surface layer of the sea bottom by divers during wide-area exploration in 2011 (NRIMCH 2017, 27). Iron pots collected from Seomeopbeol were recovered from the sand and shell layer identified during the southeast Shingoji probe survey in the first underwater excavation survey in 2012 (NRIMCH 2014, 33-34). The components of corrosion product samples were analyzed using Scanning Electron Microscope-Energy Dispersive Spectroscope (SEM-EDS) and the external characteristics of the point where certain components (P, S) were detected were observed. Then they were powdered and the compound was identified through X-ray Diffraction (XRD) analysis. Concentration of desalination solution was measured using Ion Chromatography (IC) to measure concentration of anions (F-, Cl-, SO42, NO3-, PO43-) to identify the relationship between SEM-EDS and XRD analysis result. The number of corrosion product analysis samples was 16 in total (eight from Mado and the others from Seomeopbeo) and the points (55 points in Mado and 41 points in Seomeopbeol, 96 points in total) subjected to SEM-EDS analysis were selected with 40x magnification of stereoscopic microscope images were recorded using digital recording device attached. Conditions of SEM-EDS analysis include voltage of 15-20 kV, WD 10 mm, spot size 25, measurement time of 60 seconds and magnification up to 9,000 times. Conditions of XRD analysis for 16 powdered samples after 2 �SEM-EDS and one additional sample (corrosion product of iron pot from Mado shipwreck no. 4) were voltage of 40 kV, current of 30 mA, and target Cu. For desalination solution analysis, 16 samples (eight from Mado, the others from Seomeopbeol) were prepared and anion concentration was measured using IC. As Cl- concentration of the desalination solution sample was expected to be very high, it was diluted with ultrapure water 100 times and cellulose filter was used to remove impurities in the sample and then anion analysis was conducted. STUDY RESULTS Analysis of corrosion product When sulfate reducing bacteria is involved in the corrosion process, the high content of phosphorus and sulfur may be detected in the corrosion products (Lee Yong-deuk et al. 1996, 256), SEM-EDS analysis was conducted to check whether these two components are detected and their content. The results of analyzing corrosion products showed that sulfur was detected in 15 samples except for one sample from Mado (MD6). The maximum sulfur level was 63.61 wt per cent (MD8) in samples from Mado and 25.13 wt per cent (SE7) in samples from Seomeopbeol sea area and other samples contained 0.64~23.02 wt per cent. Among them MD8 is characterized by maximum sulfur content of 11.51 wt per cent and phosphorus content of 12.17 wt per cent. This result can be interpreted that sulfate reducing bacteria influenced the corrosion process of iron pots collected from Mado and Seomeopbeol. However, these compounds were identified with the identification of mackinawite (FeS) in MD1 and other samples identified iron oxides such as siderite (FeCO3) or goethite (FeOOH) formed by the influence of concretion. Table 1. Results of analysis on corrosion product of iron pot recovered from Mado (EDS, XRD) Sample Maximum content of major ingredient (wt per cent) Compound Name (Chemical Formula) P S Ca MD1 - 11.85 10.12 Magnetite (Fe3O4) calcite (CaCO3) mackinawite (FeS) MD.2 - 1.40 0.51 Magnetite (Fe3O4) siderite (FeCO3) MD3 - 2.53 - Siderite (FeCO3) MD4 - 6.65 - Siderite (FeCO3) MD5 - 1.54 - Magnetite (Fe3O4) quartz (SiO2) MD6 - - - Magnetite (Fe3O4) siderite (FeCO3) MD7 - 63.61 - Siderite (FeCO3) MD8 12.17 11.51 - Magnetite (Fe3O4) Table 2. Results of analysis of corrosion product of iron pot recovered from water Seomeopbeol sea area (EDS, XRD) Sample Maximum content of major ingredient (wt per cent) Compound Name (Chemical Formula) P S Ca SE1 - 0.64 1.36 Siderite (FeCO3) magnetite (Fe3O4) goethite (FeOOH) SE2 0.27 1.11 3.63 Siderite (FeCO3) SE3 - 2.96 0.48 Siderite (FeCO3) magnetite (Fe3O4) SE4 - 0.87 1.51 Siderite (FeCO3) goethite (FeOOH) SE5 - 8.48 4.09 Magnetite (Fe3O4) goethite (FeOOH) SE6 0.17 4.04 - Goethite (FeOOH) SE7 - 25.13 37.80 Siderite (FeCO3) magnetite (Fe3O4) SE8 - 23.02 31.61 Siderite (FeCO3) magnetite (Fe3O4) goethite (FeOOH) 3 �Iron sulfide such as Mackinawite or pyrite (FeS2) are formed together with oxides such as FeOOH, serving as the evidence to show corrosion by sulfate reducing bacteria (Lee Jae-ik and Seo Myeong-po 1992, 63), but this study did not obtain results with unique characteristics. However, according to previous studies, iron sulfide in a honeycomb structure, which is easily oxidized to calcium sulfate in the form of iron crystals, was observed in European old ships using iron nails (Kim Yong-han 1987, 151-152), SEM observation confirmed similar type of corrosion products in SE5 and SE7. In addition, samples from Seomeopbeol contain large amounts of Calcium and SE7 and SE8 showed high concentration of sulfur so it is considered to be the result of oxidation of iron sulfide. However, in the XRD analysis, the identification of relevant compounds (CaSO4, etc.) was not done and SEM observation did not confirm unique characteristics, requiring further research on this matter. Analysis of desalination solution Sixteen samples were collected from desalination solution from six pots, three from each area including MT64 and SE405 where corrosion product analysis sample was collected (red square in Table 3 and 4) to conduct anion analysis. The analysis results showed that Table 3 and 4 Cl- and SO42concentration was higher overwhelmingly than other anions and EDS ingredient analysis showed 20 ppm or higher PO43- in the MT64 sample where phosphorus was detected. PO43- was measured in the sample from primary desalination solution of YDS1 and YDS on December 4, 2013 once respectively but it was not identified in samples after that. Table 3. Results of analyzing desalination solution of iron pot excavated from Mado (IC) Sample (date) M3S262 (‘12.3.15) M3S262 (‘12.5.24) M3S262 (‘12.6.28) MS76 (’12.4.25) MS76 (’12.6.7) MS76 (‘12.7.12) MT64 (’12.3.22) MT64 (’12.5.16) Anion concentration (ppm) FClSO420.18 60.74 241.41 0.16 48.11 104.80 0.14 30.24 72.29 0.20 14.54 41.83 0.37 13.96 40.22 NO33.49 - PO43- 0.28 14.33 29.56 - - 0.28 0.25 223.83 109.66 271.22 194.79 - 25.44 22.64 Table 4. Results of analyzing desalination solution of iron pot excavated from Seomeopbeol (IC) Anion concentration (ppm) FCl- SO42- NO3- PO43- SE403 (‘14.1.7) 0.12 41.05 100.64 - - SE403 (‘14.3.5) SE403 (‘14.5.13) YDS1 (‘13.12.4) YDS1 (‘14.8.5) YDS1 (‘15.4.7) YDS4 (‘13.12.4) YDS4 (‘14.4.17) 0.27 0.07 0.77 0.01 0.01 0.46 0.05 13.62 10.79 1530.31 172.80 110.51 439.99 55.61 17.19 7.66 84.31 27.17 54.32 48.19 10.04 6.00 3.97 7.19 16.27 15.68 - Sample (date) As presented in Table 3 and 4, SO42- was clearly detected in the desalination solution from the two sites. Generally, Cl- dissolution is the focus in the process of stabilization considering the impact of sea water containing large amounts of salt for iron artifacts excavated from underwater but as shown in the result, whether SO42- remains or not should be checked mandatorily. 4 �CONCLUSIONS This study was conducted to obtain information on effective methods of conservation treatment by analyzing corrosion products of iron artifacts collected from the Middle West Sea and desalination solution. The iron artifacts recovered from waters included artifacts lifted by removing strong and dense mud layers and artifacts buried near the surface layer or exposed on the seabed surface. In order to find out the pattern of corrosion of iron artifacts, wide area exploration of waters of Mado, Taean and excavation survey in waters of Seomeopbeol, Ongjin were conducted and the corrosion product of iron pots lifted and desalination solution were used as samples for research. In the iron corrosion process, when sulfate reducing bacteria is involved, significant amounts of sulfur and phosphorus can be detected. Therefore, in this study, SEM-EDS analysis was conducted for the components of iron pot corrosion products from Mado and Seomupbeol. Previous studies on iron test piece corrosion by seawater, mud (collected from Mado) and Na2S water solution, ingredients such as Sulfur or Phosphorus were not detected at all (Kim Taek-joon 2013, 47-50). In our SEM-EDS analysis on corrosion products, a large amount of sulfur was detected in most samples and one sample from Mado contained 12.17 wt per cent of phosphorus. Sulfate reducing bacteria is confirmed in the process of iron pot from Mado and Seomupbeol. However, in the XRD analysis, there were no clear results except for the identification of mackinawite (FeS) in one sample. In the anion analysis of desalination solution, highly concentrated Cl- and SO42- were measured and it is considered to be related to the identification of sulfur as the main ingredient of corrosion products. Sulfur and SO42- were major factors that influence the corrosion of iron artifacts collected from the Middle West Sea. However, it was not possible to obtain specific information on how these factors are involved in corrosion of iron artifacts. Follow-up research will involve sulfate reducing bacteria and further analysis of corrosion products of iron artifacts collected from various sea areas. Acknowledgements I would like to thank people from the Conservation Science Lab of NRIMCH for helping with the analysis of samples. Bibliography Fujii, Tetsuo. Countermeasures against Corrosion of Metal Materials. Tokyo: Nikkan Industrial Newspaper, 2009 (In Japanese). Kim, Taek-joon. “Study of Corrosion Characteristics of Iron Objects Excavated from Taean Mado Waters.” Master’s thesis, Hanseo University, 2013 (In Korean). Kim, Yonghan, “Conservation and Restoration of the Shipwreck.” Conservation Studies 8 (1987): 123-148 (In Korean). Lee, Jae-ik. and Seo, Myeongpo. “Corrosion of metals by microorganisms.” Journal of Corrosion Science 21, no. 1 (1992): 50-66 (In Korean). Lee, Yong-deuk. Ryu, Seung-ki. and Kim, Youngho. “Microbially Influenced Corrosion of Stainless Steels.” Journal of Corrosion Science 25, no. 2 (1996): 249-259 (In Korean). Noboru, Masko. Anticorrosion Technique Manual. Tokyo: Sanbi Printing, 1984 (In Japanese). North, Neil A. MacLeod, Ian D. “Corrosion of Metals.” In Corrosion of Marine Archaeological Objects, edited by Colin Pearson, 68-98. London: Butterworths, 1987. NRIMCH. Waters off Taean-Mado Underwater Excavation, Series of Research Report of NRIMCH 62. Taean: NRIMCH, 2017 (In Korean). NRIMCH. Incheon Ongingun Yeongheungdo Shipwreck Underwater Excavation, Series of Research Report of NRIMCH 35. Mokpo: NRIMCH, 2014 (In Korean). Paik, Yeongnam. and Yeo, Woonkwan. “A Study of Marine Corrosion Phenomena of Metals.” Theses Collection of Kyung Hee University 10 (1980): 673 (In Korean). 5 � Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource 2023 Session 14: Conservation Treatment of Underwater Cultural Heritage Subject The topic of the resource Session 14 papers Description An account of the resource Papers presented at Session 14 of the 2023 Asia Pacific Regional Conference on Underwater Cultural Heritage Creator An entity primarily responsible for making the resource Asia Pacific Regional Conference on Underwater Cultural Heritage Publisher An entity responsible for making the resource available The Museum of Underwater Archaeology Date A point or period of time associated with an event in the lifecycle of the resource November 2023 Rights Information about rights held in and over the resource Asia Pacific Regional Conference on Underwater Cultural Heritage Language A language of the resource English Rights Holder A person or organization owning or managing rights over the resource. Asia Pacific Regional Conference on Underwater Cultural Heritage Document A resource containing textual data. Note that facsimiles or images of texts are still of the genre text. Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Study on Corrosion Factors of Iron Artifacts Recovered from the Middle West Sea Description An account of the resource This study investigates corrosion process through analysis of corrosion products and desalination solution as a precedent study to present proper conservation treatment methods for iron artifacts collected from the middle West Sea. Depending on the environment where the iron artifacts were buried underwater, the corrosion patterns may be different. In order to treat the heritage stably and effectively for conservation, the major corrosion factors and information to remove or control the factors should be obtained. The underwater environment is rich in water, oxygen and salt, and it is very easy for iron artifacts to be corroded. In an environment where oxygen supply is little like seabed mud, anaerobic corrosion may occur. The iron artifacts in the seabed may be deeply buried in the mud or exposed on the surface of the seabed. This study intends to obtain information on the corrosion pattern of iron artifacts collected from the seabed surface of middle West Sea. In addition to those deeply buried in dense silt, there are also cases of recovering those exposed on the seabed or shallowly buried in the surface layer. In this study, we obtained information on the corrosion patterns of iron artifacts recovered from the seabed layer in the central West Sea.The samples used in the study were corrosion products from iron artifacts excavated from waters of Mado, Taean and of Seomeopbeol, Ongjin and desalination solution and the major components of corrosion products and anions of desalination solution were analyzed using Scanning Electron Microscope-Energy Dispersive Spectroscope (SEM-EDS) and X-ray Diffraction (XRD), Ion Chromatography (IC). The analysis result shows that major components including P, S and Mackiwanite (FeS) were identified as compounds related to it. In the desalination solution, high concentration of Cl - and SO4 2- was measured. It is expected that this study result can be utilized as essential data for establishing methods for effective and systematic conservation of iron artifacts excavated from underwater and it is intended to continue additional studies such as analysis on corrosion product of iron artifacts recovered from various waters and corrosion reproduction experiment through collaboration with various fields. Creator An entity primarily responsible for making the resource Kim Taek-joon Yoo Dae-young Lee Hyeon-ji Publisher An entity responsible for making the resource available The Museum of Underwater Archaeology Date A point or period of time associated with an event in the lifecycle of the resource 2023 Language A language of the resource English Bibliographic Citation A bibliographic reference for the resource. Recommended practice is to include sufficient bibliographic detail to identify the resource as unambiguously as possible. Taek-joon, Kim, Yoo Dae-young, and Lee Hyeon-ji. 2023. “Study on Corrosion Factors of Iron Artifacts Recovered from the Middle West Sea.” Edited by Jennifer Craig, Jay Mok, T. Kurt Knoerl, and Juhee Kim. In Proceedings of Fifth Asia Pacific Regional Conference on Underwater Cultural Heritage: Gwangju, The Republic of Korea, November 13-18 2023. The Museum of Underwater Archaeology. URL: https://apconf.omeka.net/exhibits/show/apconfproceedings/item/1962 Asia-Pac Session 14 2023 https://apconf-much.org/proceedings/files/original/1bcda376a910a9e09dd68952d56563fc.pdf eb8bdf725bebbacf088e37cf8c3023bb PDF Text Text Development and State of Research on Conservation Treatment of Underwater Cultural Heritage in Korea Bo-hyun Lee (Conservation Science Research Curator, National Research Institute of Maritime Cultural Heritage) ABSTRACT Conservation treatment of large waterlogged wooden historic ships improved gradually as historic ships were excavated one after another. After 40 years, exhibition halls and conservation treatment centers have been established and in operation in Mokpo and Taean. Taean is equipped with Asia's largest vacuum freezer and Mokpo conservation treatment place with a long history is being transformed into a new conservation treatment center. In addition, the National Research Institute of Maritime Cultural Heritage, which has Korea's only underwater cultural heritage conservation and treatment facility, has been publishing treatment reports and guidelines for many years. However, as the acidic aging was discovered on the Sinan shipwreck like the Vasa and Mary Rose, it has become an issue and various studies were conducted to identify the cause and treatment method accordingly. It is unreasonable to apply the results of test pieces in the laboratory directly to the entire Sinan shipwreck, which was restored and displayed at the exhibition hall. Therefore, it is planned to conduct a partial test gradually to find a method that can handle exhibition and treatment at the same time. Keywords: underwater cultural heritage, conservation treatment, research status, challenges List of Tables Table 1. State of conservation treatment of historic ships recovered from underwater (as of May 2023) Table 2. List of publications on conservation of underwater cultural heritage INTRODUCTION This study deals with overall matters related to the conservation treatment of underwater cultural heritage (UCH) in Korea which started in 1976. The research was partially addressed in Conservation Treatment of Historic Ships Collected from the Sea published by the National Research Institute of Maritime Cultural Heritage (NRIMCH) in 2021. This study intends to deal with the current state of research on conservation science of UCH in Korea in detail from more various perspectives. In addition, this study intends to highlight the current research projects and future tasks. We will examine the process of development before touching upon the current state of conservation science of UCH in Korea. DEVELOPMENT OF CONSERVATION TREATMENT OF UNDERWATER CULTURAL HERITAGE IN KOREA Conservation treatment of UCH in Korea began with the excavation of the Sinan shipwreck in 1976. However, excavation of the Sinan shipwreck which started in the sea, a special environment, presented many challenges from the beginning. There was no infrastructure to speak of such as professionals, budget and treatment facility and there was a big problem of how to treat super-large wooden historic ships. At that time conservation treatment technology of Japan was more advanced than that of Korea but the conservation treatment technology for wooden historic ships in East Asia was not comparable to that of Europe. Accordingly, Korea started direct exchanges with museums in many parts of Europe including Switzerland, Germany, Denmark, Sweden and the UK in order to learn Europe’s historic ship conservation treatment method and restoration technology in 1983. Korea dispatched domestic experts to international courses for wooden cultural heritage conservation sponsored by UNESCO and ICCROM and started forming academic exchanges. Thanks to this, the current state of wooden 1 �historic ships in Europe and various treatment methods became widely known in Korea. In the 1990s, the waterlogged wooden conservation treatment area took its root firmly in Korea’s cultural heritage conservation science. In addition, PEG-2 step treatment method was applied to the Sinan shipwreck through joint basic experiment and research conducted together with the German Maritime Museum. PEG-2 step is a method of impregnating a low-molecular PEG400 solution at a low concentration, and then heating the high-molecular solid PEG4000 at 40-45 °C and impregnating it to a high concentration (Kim Ik-joo 2004, 68-69). This method still works for submerged shipwrecks. Table 1. State of conservation treatment of historic ships recovered from underwater (as of May 2023) No. Name Size (length x width (m)) / No. of pieces Treatment method Date of treatment period Treatment status Location 1 Sinan shipwreck 34 x 11 / 1, 729 pieces 1981-2004 Exhibition Mokpo Museum 2 Wando shipwreck 9 x 3.5 / 1, 81 pieces 1984-1998 Exhibition Mokpo Museum 3 Dalido shipwreck 10.5 x 2.7 / 1, 33 pieces Jul. 1995- Dec. 2009 Exhibition Mokpo Museum 4 Sipyidongpado shipwreck 7 x 2.5 / 1, 14 pieces 2004-2016 Exhibition Mokpo Museum 5 Jindo shipwreck 16.8 x 2.3 / 1, 2 pieces Jun. 1992-present Dried Mokpo Conservation Center 6 Anjwado shipwreck 14.7 x 4.5 / 1, 39 pieces Aug. 2005-present Dried Mokpo Conservation Center 7 Daebudo shipwreck 6.6 x 1.4 / 1, 7 pieces Dec. 2006-present Dried Mokpo Conservation Center 8 Taean shipwreck 8.2 x 1.5 / 1, 7 pieces May 2008-present Reinforced (70%) Taean Conservation Center 9 Mado no. 1 shipwreck 10.8 x 3.7 / 1, 40 pieces Oct. 2009-present Reinforced (70%) Taean Conservation Center 10 Mado no. 2 shipwreck 12.8 x 5 / 1, 41 pieces - Oct. 2010-present Desalinated Taean Conservation Center 11 Mado no. 3 shipwreck 12 x 8 / 1, 21 pieces - - Conserved on site - 12 Yeongheungdo shipwreck 6 x 1.5 / 1, 3 pieces - Jul. 2013-present Desalinated Mokpo Conservation Center 13 Mado no. 4 12 x 5 / 1, 22 pieces - - Conserved on site - 14 Daebudo shipwreck no. 2 9.2 x 2.9 / 1, 50 pieces - Jul. 2015-present Desalinated Mokpo Conservation Center 15 Jebudo shipwreck no. 1 9.2 x 2.9 - - Conserved on site - 16 Jebudo shipwreck no. 2 9.2 x 2.9 - - Conserved on site - shipwreck PEG 2-Step method (400/4000) 2 �The Sinan shipwreck was unveiled in 2004 after 18 years of conservation treatment and 10 years of hull restoration. After excavation of Sinan shipwreck, historic ships were discovered one after another in the West Sea of Korea, including Wando shipwreck (1984), Jindo Pyokpari Tongnamu Pae (1992), Dalido shipwreck (1995), Sipyidongpado shipwreck (2004), Anjwado shipwreck (2005), Daebudo shipwreck (2006), Taean shipwreck (2008), Mado shipwreck no. 1 (2009), Mado shipwreck no. 2 (2010), Mado shipwreck no. 3 (2011), Yeongheungdo shipwreck (2013), Mado shipwreck no. 4 (2014), Daebudo shipwreck no. 2 (2015), Jebudo shipwreck no. 1 (2016) and Jebudo shipwreck no. 2 (2016). Table 1 summarizes where these ships have been treated for conservation or in the process of conservation treatment, while some are conserved on site. As historic ships have been excavated continuously, Korea’s underwater archeology and conservation treatment technology of historic ships have grown remarkably. The conservation treatment infrastructure, organization and budget have become one of the top in Asia. The NRIMCH, which started in Mokpo Conservation Center in 1982, is now operating museums in Mokpo (Jeollanam-do) and Taean (Chungcheongnam-do) respectively and has its own conservation treatment facility. Mokpo conservation center, which started with two employees about 42 years ago, has now ten employees in Mokpo and five in Taean. Taean conservation center has installed and run test operation of Asia's largest vacuum freezer. CURRENT STATE OF CONSERVATION SCIENCE FOR UCH IN KOREA Cultural heritage excavated from water is very diverse in materials such as metal, ceramics, wood, and stone. Various kinds of artifacts are excavated from ships as ships are a carrier of transport goods, which contains living space on the ship. Therefore, conservation methods should be applied differently depending on materials. Korea has already prepared guidelines on conservation treatment by material with dividing artifacts into those excavated from land and those from underwater and has treated them by referring to these guidelines. Recovered Artifacts so far are mainly made of wood (hull components, etc.) and ceramics (transport goods), so the proportion of conservation treatment for historic ships and ceramics is high. Out of 50,762 artifacts excavated, 47,036 pieces are ceramics, accounting for more than 93 per cent. In addition, all five pieces which are nationally designated cultural property and in possession are ceramics. Natural scientific analysis of ceramics excavated from the sea began in earnest in the early 2000s. Depending on the excavation site and function, various analyzes have been conducted, such as the base soil, firing temperature, minor components, and estimation of the production site. Starting from this year, research is being conducted to scientifically reveal the relationship between the production and the consumption areas, and the correlation between the times and materials based on the existing research results. 3 �Table 2. List of publications on conservation of UCH Major content No . Title Date 1 Guideline on Conservation Treatment of Artifacts Excavated from Underwater 2013 A guideline on conservation treatment of artifacts excavated from underwater including treatment cases. 2 Conservation Manual of Maritime Archaeological Objects in Korea 2014 English version of the guideline on conservation treatment of artifacts excavated from underwater, introducing how to treat wooden artifacts, ceramics and metal artifacts. 3 Conservation Treatment of Ceramics Excavated from Underwater 2020 Classifying pottery which was excavated the largest in volume into pottery, celadon and white porcelain and reporting treatment methods and cases. 4 Conservation Treatment of historic Ships Excavated from Underwater 2021 Containing the process of conservation treatment for Sinan shipwreck, Wando shipwreck, Jindo shipwreck, Dalido shipwreck and Sipyidongpado shipwreck and natural scientific analysis details. 5 Comprehensive Report on Sinan Ship Conservation Project 2022 Summarizing the research on analysis on aging of Sinan shipwreck and conservation treatment method comprehensively. Cover ISSUES REGARDING CONSERVATION SCIENCE OF UCH IN KOREA Korea's historic ship conservation treatment can be divided into two fields. First, conservation treatment of waterlogged wood using PEG and infrastructure. Second, neutralization treatment of acidic aging that occurs in historic ships treated with PEG. First, the conservation of waterlogged wood with PEG is to treat the wood using PEG-2 step method as mentioned earlier. Reinforcement treatment is done with PEG 400-PEG 4000 and not vacuum lyophilization but control drying is done for conservation. Taean conservation treatment room is equipped with the latest vacuum lyophilizer that can treat 10 m. The Mokpo Conservation Center needs facility replacement as it was established in 1981. Conservation treatment of waterlogged wood using PEG and infrastructure The hull varies in length from about 2 m to 10 m for each member and a specially designed tank is required for reinforcement treatment. The tank should be made of stainless steel with strong corrosion resistance, and a heat source (boiler hot water and electric coil) and temperature sensor should be attached to maintain a constant temperature. In addition, in order to mix the high molecular weight 4 �PEG well, a solution circulation pump facility that can exchange the upper and lower solutions is required. Moreover, boiler, expansion tank, and hot water pipe facilities should be in place in the boiler room upon heating treatment using boiler hot water. Assuming that the hull members are 5-6 m long, 0.1 m thick, and 0.5 m wide, the weight usually reaches 300 kg. Hoists, cranes, and lifts that can lift and move these members safely and easily are essential. Therefore, in order to conserve and treat large-sized timbers such as hulls, a large-scale processing facility should be established. The NRIMCH started seismic construction of PEG reinforcement treatment in 2022, and planned PEG reinforcement treatment internal construction (water drainage, piping, electricity, etc.) and tank (10 m x 1 m x 1 m * 1 unit, 6 m x 1 m x 1 m * 6 units), desalination treatment room improvement in 2025 and drying treatment room improvement in 2026. Acidic aging of historic ships treated with PEG Acidic aging is caused by the presence of iron compounds in wood and prolonged exposure, and the same phenomenon has already appeared in foreign ships such as Vasa, Mary Rose, and Batavia, and efforts have been made to solve this problem. The Sinan shipwreck experienced acidic aging since 2010 and various methods were tried inside and outside the laboratory to solve the problem. Constant temperature and humidity monitoring has been conducted to secure raw data and the aging condition of the hull has been recorded with 3D scanning using 3D digital methods. After that, surface contaminants were removed through dry cleaning, and a deterioration map was also prepared to compare changes in surface conditions. Integrated Pest Management is being implemented to prevent harmful organisms in exhibition halls and storage areas and to establish a stable conservation environment. Various acidic aging treatment experiments were conducted in the laboratory and the Comprehensive Report on Sinan Ship Conservation Project that contains the results of experiments was recently released. This experiment is the result of the experiment on a test piece carried out in the laboratory, but it is difficult to practically apply chemical treatment to the 924 m2 exhibition room. Therefore, the Heritage Science Team of the NRIMCH plans to expand the treatment area in the future, starting with a direct spot test on the Sinan shipwreck, which was exhibited from this year. Our future task will be how to open the exhibition site to the audience safely as the conservation treatment is underway in the exhibition hall. Acknowledgements I would like to thank organizers and committee members for making a decision for Korea to host APConf 2023. I would also like to express my gratitude to my seniors and colleagues who have worked hard for conservation science at the NRIMCH. Bibliography Kim, Ik-Joo. “Conservation of Waterlogged Ancient Ship in Korea.” The Conservation and Restoration of Shinan Ship, the 20 Years History (2004): 58-71 (In Korean). NRIMCH. Conservation Manual of Maritime Archaeological Objects in Korea, Series of Research Report of NRIMCH 31. Mokpo: NRIMCH, 2013 (In Korean). NRIMCH. The Conservation of Ceramics Excavated from Underwater, Series of Research Report of NRIMCH 61. Mokpo: NRIMCH, 2020 (In Korean). NRIMCH. The Conservation of Shipwrecks Excavated from Underwater, Series of Research Report of NRIMCH 63. Mokpo: NRIMCH, 2021 (In Korean). NRIMCH. The Comprehensive Report on Conservation Project of Sinan Shipwreck, Series of Research Report of NRIMCH 74. Mokpo: NRIMCH, 2022 (In Korean). 5 � Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource 2023 Session 14: Conservation Treatment of Underwater Cultural Heritage Subject The topic of the resource Session 14 papers Description An account of the resource Papers presented at Session 14 of the 2023 Asia Pacific Regional Conference on Underwater Cultural Heritage Creator An entity primarily responsible for making the resource Asia Pacific Regional Conference on Underwater Cultural Heritage Publisher An entity responsible for making the resource available The Museum of Underwater Archaeology Date A point or period of time associated with an event in the lifecycle of the resource November 2023 Rights Information about rights held in and over the resource Asia Pacific Regional Conference on Underwater Cultural Heritage Language A language of the resource English Rights Holder A person or organization owning or managing rights over the resource. Asia Pacific Regional Conference on Underwater Cultural Heritage Document A resource containing textual data. Note that facsimiles or images of texts are still of the genre text. Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Development and State of Research on Conservation Treatment of Underwater Cultural Heritage in Korea Description An account of the resource Conservation treatment of large waterlogged wooden historic ships improved gradually as historic ships were excavated one after another. After 40 years, exhibition halls and conservation treatment centers have been established and in operation in Mokpo and Taean. Taean is equipped with Asia's largest vacuum freezer and Mokpo conservation treatment place with a long history is being transformed into a new conservation treatment center. In addition, the National Research Institute of Maritime Cultural Heritage, which has Korea's only underwater cultural heritage conservation and treatment facility, has been publishing treatment reports and guidelines for many years. However, as the acidic aging was discovered on the Sinan shipwreck like the Vasa and Mary Rose, it has become an issue and various studies were conducted to identify the cause and treatment method accordingly. It is unreasonable to apply the results of test pieces in the laboratory directly to the entire Sinan shipwreck, which was restored and displayed at the exhibition hall. Therefore, it is planned to conduct a partial test gradually to find a method that can handle exhibition and treatment at the same time. Creator An entity primarily responsible for making the resource Bo-hyun Lee Publisher An entity responsible for making the resource available The Museum of Underwater Archaeology Date A point or period of time associated with an event in the lifecycle of the resource 2023 Language A language of the resource English Bibliographic Citation A bibliographic reference for the resource. Recommended practice is to include sufficient bibliographic detail to identify the resource as unambiguously as possible. Lee, Bo-hyun. 2023. “Development and State of Research on Conservation Treatment of Underwater Cultural Heritage in Korea.” Edited by Jennifer Craig, Jay Mok, T. Kurt Knoerl, and Juhee Kim. In Proceedings of Fifth Asia Pacific Regional Conference on Underwater Cultural Heritage: Gwangju, The Republic of Korea, November 13-18 2023. The Museum of Underwater Archaeology. URL: https://apconf.omeka.net/exhibits/show/apconfproceedings/item/1961 Asia-Pac Session 14 2023 https://apconf-much.org/proceedings/files/original/8cb2358c19528ea076a5ca02c4832296.pdf 2dd5bc09eb01eb01409102a38ebd5571 PDF Text Text Antimicrobial hydrogel patches for deacidification and conservation of waterlogged archaeological wood Xiaohang Suna, Junjie Chena, Xuanwei Zhangb, Qiang Chena* a School of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai Campus, Zhuhai, Guangdong Province, China 519082 b Marinetime Silk Road Museum of Guangdong, HVFF+3H3, Jiangcheng District, Yangjiang, Guangdong Province, China, 529536 *E-mail: chenqiang3@mail.sysu.edu.cn ABSTRACT The Nanhai No. 1 hull, a Chinese merchant ship sank during the Southern Song dynasty and excavated from the South China Sea, is an example of underwater cultural heritage waterlogged wood that has been preserved in situ for centuries. Although the overall structure of the wooden artifacts is still intact they are severely degraded and acidified. It is now urgent to explore effective approaches for its conservation, we explore the feasibility of antimicrobial hydrogel patches. Antimicrobial hydrogel patches dispersed with antibacterial and deacidification nanoparticles simultaneously deacidify, moisturize, and reinforce both antibacterial and mechanical aspects of waterlogged wood. In the construction of the antimicrobial hydrogel patches, the double network hydrogel was used to prepare the hydrogel substrate with stretch and mechanical strength. We have successfully applied the antimicrobial hydrogel patches to the waterlogged wood from Nanhai No. 1, with the support of the Maritime Silk Road Museum of Guangdong. We demonstrate here the advantages of hydrogel patches to protect waterlogged wood with testing in deacidification, compression and antimicrobial. KEYWORDS: Underwater cultural heritage waterlogged wood; Antibacterial (preserve); Nanhai No. 1; Deacidification; Antimicrobial (preventative); Mechanical support (protect against the harsh external conditions) INTRODUCTION In 2007, the 800-year-old Nanhai No.1 shipwreck hull was raised from the seabed and moved to the Marine Silk Road Museum, where it was conserved (Z. Liu et al. 2018). Early studies of the wood at the museum showed that the structural damage of the underwater cultural heritage (henceforth UCH) waterlogged wood, composed of softwoods, was severe to not withstand long-term spray deacidification and moisture retention (Huang et al. 2021; R. Li et al. 2022; Z. Liu et al. 2018; Yin et al. 2019). As the archaeological excavation continues on the Nanhai No. 1, like other conservation efforts the severe acidification and salt deposition on the surface is an important challenge for the protection of the UCH (Amornkitbamrung et al. 2015; Babiński et al. 2017; Baglioni and Giorgi 2006; Cavallaro et al. 2017; Chelazzi, Giorgi, and Baglioni 2006; Dong et al. 2010; Durán et al. 2016; Eriksen, Gregory, and Matthiesen 2017; Giorgi, Chelazzi, and Baglioni 2005; Giorgi et al. 2002; L. Liu et al. 2019; Mahltig et al. 2008; Majka, Babiński, and Olek 2017; Piotrowska and Konieczny 2015; Poggi et al. 2016; Sandström, Fors, and Persson 2003; Sandström et al. 2002; Schofield et al. 2011; Walsh-Korb 2022; Walsh-Korbs and Avérous 2019; Y. Li et al. 2022; Zelinka 2014; Zhou, Wang, and Hu 2021). Temperature, salinity, fungi, and bacteria are the cause of the severe cell wall decay (Capretti et al. 2008; Colombini et al. 2009; Hoffmann and Jones 1989. To neutralize the sulfuric acid and add antimicrobial protection for UCH waterlogged wood we prepared and applied an antimicrobial hydrogel patch. Antimicrobial hydrogel patches dispersed with antibacterial and deacidification nanoparticles simultaneously deacidify, moisturize, and reinforce both antibacterial and mechanical aspects of waterlogged wood (Gong 2014; Gong et al. 2003). This antimicrobial hydrogel patch served as mechanical support, deacidification, and antibacterial functions, during post-excavation conservation and prior to the addition of consolidates (Bai et al. 2019). We conducted 1 �a thorough literature review of shipwreck conservation of waterlogged woods; here we demonstrate in collaboration with the Maritime Silk Road Museum of Guangdong the advantages of antimicrobial hydrogel patches to protect waterlogged wood on the Nanhai No. 1 hull with testing in deacidification, compression, and antimicrobial. EXPERIMENTS Materials The UCH waterlogged wood from the Nanhai No. 1 shipwreck was generously provided by the Maritime Silk Road Museum of Guangdong with a maximum moisture content of around 529%. The UCH waterlogged wood was stored in 0.5wt% isothiazolinone solution and washed with excess amount of water three times prior to conservation. The following chemicals were purchased: Acrylamide (AR, 99.0%) and sodium citrate (98%) from Aladdin; Potassium persulfate (GR, 99.9%), potassium bicarbonate (AR, 99.5%), and N,N,N',N'-Tetramethylethylenediamine (99%) from Macklin; N,N-methylenebisacrylamide (MBAA,98%) from Maya Reagent; Silver nitrate (99%) from Alfa Aesar; Calcium Sulfate (97%) from Rhawn; and sodium alginate (AR, 98%) from RYON. All chemicals were used directly without additional purification. Method We prepared the antimicrobial hydrogel patches and performed three tests: deacidification, compression and antimicrobial. Preparation of antimicrobial hydrogel patches 12.44grams (g) of acrylamide and 1.56g of sodium alginate were dissolved in deionized water to form an acrylamide solution with a water content of 60-80 per cent by weight (wt%). After degassing the solution for one day, we added 0.0018g and 0.0036g of silver nitrate and 0.2g sodium citrate. Then we added 0.5g potassium persulfate, 0.0074g MBAA, 0.031g tetramethylethylenediamine and potassium bicarbonate (KHCO3) at 1.5g, 2.5g, and 3.5g. The solution was transferred to a transparent mold and exposed to UV light (254nanometers (nm), 8 watts (W) power output) for one hour. The resulting hydrogel was carefully removed from the molded and immersed in calcium sulfate solution for 20-40 minutes. Deacidification test The Nanhai No. 1 UCH waterlogged wood was wrapped for three hours with the antimicrobial hydrogel patch (see recipe above). The pH of the UCH waterlogged wood was measured by soaking 1g in 30g of deionized water for 30 minutes and measuring the pH of the soaking water (Mettler Toledo, FE28). The pH meter was calibrated with a standard solution before use. Compression test A compression test was conducted using a universal tensile tester (Haida Instrument, HD-A513). The displacement as a function of force was measured for the synthesized hydrogels with the KHCO3 concentration at 1.5g, 2.5g, and 3.5g and compression speed of 116 millimeters per minute (mm/min). Antimicrobial test The antimicrobial performance of the hydrogels was measured via disk diffusion test based on Oxford cup method. Briefly, the prepared agar medium was sterilized at 121°C for 15 minutes, and cooled to about 55-50°C before pouring into a petri dish to form the bottom layer of agar gel. Then, E. coli culture grown in sterilized lysogeny broth (LB) media was applied on the surface of the agar media. 2 �After one day when the E. coli culture completely covers the agar media, the prepared hydrogel was grinded into a flowable state and added dropwise into an Oxford cup. With 37°C and one day incubation, the antimicrobial performance was evaluated based on the zone of inhibition around the Oxford cup. RESULTS AND DISCUSSION In this paper, an antimicrobial hydrogel patch used in the early stages of UCH waterlogged wood conservation was prepared using weak alkaline compounds. Fig. 1a shows a sample of the waterlogged wood. Water was sprayed routinely to maintain the water content of the waterlogged wood. Waterlogged wood, on the hull of Nanhai No.1 shipwreck, in some areas show heavy precipitation and bacterial decomposition (Fig. 1b 1c and 1d). Figure 1 waterlogged wood (a) with precipitation cleaned; (b) on the hull of Nanhai No.1 shipwreck; (c) and (d) with severe bacterial decomposition. Another advantage of the hydrogel deacidification material is that it is soft and easily stretches to change shape. The tensile and compression properties were measured. Fig. 2a and 2b are photographs of released and stretched hydrogel, respectively. More than 1000% elongation was achieved with the polyacrylamide/alginate hydrogel with silver nanoparticles dispersed. 3 �Figure 2 polyacrylamide/alginate hydrogel (a) at rest; (b) tensioned and elongated; (c) graph of compression with different KHCO3 concentrations. The hydrogels with 0.5% and 2.5% KHCO3 are close in Young’s modulus, while the hydrogel with 2.5% KHCO3 has higher Young’s modulus (Fig 2c), which might be caused by the difference in ionic crosslinking of silver and potassium ions. The hydrogel with potassium percarbonate was used to wrap the waterlogged wood (Fig. 3a-c). The weak alkaline KHCO3 neutralized the sulfuric acid in the waterlogged wood, which resulted in a pH increase from 4.0 to 7.2 (Fig 3d). It was also confirmed that above 0.5% KHCO3 concentration, the increase in KHCO3 did not contribute to the pH increase remarkably. Gentle adhesion of the hydrogel to the wood neutralization occurs immediately, which lead to fast and significant pH increase. We suspect this is due to the large water content of the hydrogel, while also performing the adhesion underwater, is homogeneous. Figure 3 antimicrobial hydrogel (a) patch (b) patch and waterlogged wood (c) wrapped around waterlogged wood; (d) bar graph of pH test with different KHCO3 concentrations. The results of hydrogel antibacterial experiments proved it can protect waterlogged wood from bacterial degradation. When 30 μg/mL silver nitrate in the hydrogel was converted to silver nanoparticles, the antimicrobial properties of the hydrogels became sufficient to prevent bacterial degradation. Comparing Fig 4b and 4c, we see the increase of the silver nanoparticles from 30 μg/mL 4 �silver nitrate converted to silver nanoparticles to 60 μg/mL silver nitrate converted to silver nanoparticles had less effect on the increase in antimicrobial properties. Figure 4 antimicrobial hydrogel with silver nitrate converted to silver nanoparticles (a) control sample without;(b) zones of inhibition caused by 30 μg/mL; (c) zones of inhibition caused by 60 μg/mL. CONCLUSIONS In this paper, we explore the feasibility of using antimicrobial hydrogel patches with excellent mechanical strength for conservation of waterlogged wood. We focused our testing on antimicrobial hydrogels deacidification and antibacterial properties. We noted the prepared hydrogel patches match well with weak alkaline and high water content properties to carry out ion exchange to reduce the acidity. Double network polymer structure was utilized to increase the stretch of the hydrogel, which provides mechanical support to the highly decayed softwood. These antimicrobial hydrogel patches can perform targeted restoration and preservation as indicated by our research and testing of UCH waterlogged wood from Nanhai No.1 with the help of the Maritime Silk Road Museum of Guangdong. AUTHOR INFORMATION Mailing address: School of Chemical Engineering and Technology, Sun Yat-sen University Zhuhai, Guangdong Province 519082 China; Email: chenqiang3@mail.sysu.edu.cn Xiaohang Sun, Junjie Chen, Xuanwei Zhang, Qiang Chen* contributed equally to this work. All authors have given approval to the final version of the manuscript. ACKNOWLEDGMENT This work was supported by the National Natural Science Foundation of China (51972264). 5 �Bibliography Amornkitbamrung, Lunjakorn, Tamilselvan Mohan, Silvo Hribernik, Victoria Reichel, Damien Faivre, Adriana Gregorova, Patricia Engel, Rupert Kargl, and Volker Ribitsch. “Polysaccharide Stabilized Nanoparticles for Deacidification and Strengthening of Paper.” RSC Advances 5, no. 42 (2015): 32950–32961. Babiński, Leszek, Ewa Fabisiak, Henryk P. Dąbrowski, and Piotr Kittel. “Study on Dimensional Stabilization of 12,500-Year-Old Waterlogged Subfossil Scots Pine Wood from the Koźmin Las Site, Poland.” Journal of Cultural Heritage 23, (2017): 119–127. Baglioni, Piero, and Rodorico Giorgi. “Soft and Hard Nanomaterials for Restoration and Conservation of Cultural Heritage.” Soft Matter 2, no.4 (2006): 293. Bai, Ruobing, Jiawei Yang, and Zhigang Suo. “Fatigue of Hydrogels.” European Journal of Mechanics - A/Solids 74, (2019): 337–370. Capretti, C., N. Macchioni, B. Pizzo, G. Galotta, Gianna Giachi, and D. Giampaola. “The Characterization of Waterlogged Archaeological Wood: The Three Roman Ships Found in Naples (Italy).” Archaeometry 50, no. 5 (2008): 855–876. Cavallaro, Giuseppe, Giuseppe Lazzara, Stefana Milioto, Filippo Parisi, and Fabio Ruisi. “Nanocomposites Based on Esterified Colophony and Halloysite Clay Nanotubes as Consolidants for Waterlogged Archaeological Woods.” Cellulose 24, no.1 (2017): 3367–3376. Cavallaro, Giuseppe, Stefana Milioto, and Giuseppe Lazzara. “Halloysite Nanotubes: Interfacial Properties and Applications in Cultural Heritage.” Langmuir 36, no.1 (2020): 3677–3689. Chelazzi, David, Rodorico Giorgi, and Piero Baglioni. “Nanotechnology for Vasa Wood De-Acidification.” Macromolecular Symposia 238, (2006): 30–36. Colombini, Maria P., Jeannette J. 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Mosselmans, and Alan V. Chadwick. “Nanoparticle De-Acidification of the Mary Rose.” Materials Today 14, no. 7–8 (2011): 354–358. Walsh-Korb, Zarah. “Sustainability in Heritage Wood Conservation: Challenges and Directions for Future Research.” Forests 13, no. 1 (2022):18. Walsh-Korbs, Zarah, and Luc Avérous. “Recent Developments in the Conservation of Materials Properties of Historical Wood.” Progress in Materials Science 102, (2019): 167–221. Yin, Liuyu, Yin Jia, Mei Wang, Huanhuan Yu, Ying Jing, Cuiting Hu, Fengyu Zhang, et al. “Bacterial and Biodeterioration Analysis of the Waterlogged Wooden Lacquer Plates from the Nanhai No. 1 Shipwreck.” Applied Sciences (Switzerland) 9, no. 4 (2019): 1–13. Zelinka, Samuel L. 2014. “Preserving Ancient Artifacts for the next Millennia.” Proceedings of the National Academy of Sciences of the United States of America 111, no. 50 (2014): 17700–17701. Zhou, Yihang, Kai Wang, and Dongbo Hu. “An Aqueous Approach to Functionalize Waterlogged Archaeological Wood Followed by Improved Surface-Initiated ARGET ATRP for Maintaining Dimensional Stability.” Cellulose 28, no. 4 (2021): 2433–2443. 7 � Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource 2023 Session 14: Conservation Treatment of Underwater Cultural Heritage Subject The topic of the resource Session 14 papers Description An account of the resource Papers presented at Session 14 of the 2023 Asia Pacific Regional Conference on Underwater Cultural Heritage Creator An entity primarily responsible for making the resource Asia Pacific Regional Conference on Underwater Cultural Heritage Publisher An entity responsible for making the resource available The Museum of Underwater Archaeology Date A point or period of time associated with an event in the lifecycle of the resource November 2023 Rights Information about rights held in and over the resource Asia Pacific Regional Conference on Underwater Cultural Heritage Language A language of the resource English Rights Holder A person or organization owning or managing rights over the resource. Asia Pacific Regional Conference on Underwater Cultural Heritage Document A resource containing textual data. Note that facsimiles or images of texts are still of the genre text. Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Antimicrobial hydrogel patches for deacidification and conservation of waterlogged archaeological wood Description An account of the resource The Nanhai No. 1 hull, a Chinese merchant ship sank during the Southern Song dynasty and excavated from the South China Sea, is an example of underwater cultural heritage waterlogged wood that has been preserved in situ for centuries. Although the overall structure of the wooden artifacts is still intact they are severely degraded and acidified. It is now urgent to explore effective approaches for its conservation, we explore the feasibility of antimicrobial hydrogel patches. Antimicrobial hydrogel patches dispersed with antibacterial and deacidification nanoparticles simultaneously deacidify, moisturize, and reinforce both antibacterial and mechanical aspects of waterlogged wood. In the construction of the antimicrobial hydrogel patches, the double network hydrogel was used to prepare the hydrogel substrate with stretch and mechanical strength. We have successfully applied the antimicrobial hydrogel patches to the waterlogged wood from Nanhai No. 1, with the support of the Maritime Silk Road Museum of Guangdong. We demonstrate here the advantages of hydrogel patches to protect waterlogged wood with testing in deacidification, compression and antimicrobial. Creator An entity primarily responsible for making the resource Xiaohang Sun Junjie Chen Xuanwei Zhang Qiang Chen Publisher An entity responsible for making the resource available The Museum of Underwater Archaeology Date A point or period of time associated with an event in the lifecycle of the resource 2023 Language A language of the resource English Bibliographic Citation A bibliographic reference for the resource. Recommended practice is to include sufficient bibliographic detail to identify the resource as unambiguously as possible. Sun, Xiaohang , Junjie Chena, Xuanwei Zhangb, and Qiang Chena. 2023. “Antimicrobial hydrogel patches for deacidification and conservation of waterlogged archaeological wood.” Edited by Jennifer Craig, Jay Mok and T. Kurt Knoerl. In Proceedings of Fifth Asia Pacific Regional Conference on Underwater Cultural Heritage: Gwangju, The Republic of Korea, November 13-18 2023. The Museum of Underwater Archaeology. URL: https://apconf.omeka.net/exhibits/show/apconfproceedings/item/1909 Asia-Pac Session 14 2023 https://apconf-much.org/proceedings/files/original/eed1593b3e75fedc02c5fbd4b3478c8c.pdf 0d57e324a1194ea90d132c64c15915b2 PDF Text Text Conserving Ropes from the Phanom-Surin Shipwreck in Thailand: Case Study on Storage and Exhibition at the National Museum of Thailand Natchaya Pattanasuttirata , Kunthida Chimmab , Puangporn Srisomboon, and Monchalus Pitisinchoochai Conservation Science Division, Office of National Museum, The Fine Arts Department, Ministry of Culture, Thailand a Natchaya.peary@gmail.com, bChimma.kun@hotmail.com ABSTRACT There are several important factors to consider when studying appropriate conservation methods for fibers in museum exhibitions or storage. This research focused on investigating the potential of using Trehalose and polyethylene glycol 4000 (PEG4000) as treatments for shipwreck rope fibers in Thailand's museums. The efficacy of these treatments was evaluated by using a twisted fiber thread to tie the torpedo jar. The initial desalinated fibers were subjected to three groups: untreated rope was dried at room temperature, ropes conserved with Trehalose, and ropes conserved with PEG4000. Identical concentrations of both the Trehalose and PEG4000 solutions started at a concentration of 25 percent brix then increased progressively to 40 percent and 60 percent brix. We employed four different analyses. We used scanning electron microscopy to study morphological properties. Prior to treatment and after treatment we compared numerical evaluation of the colour change using ΔE* values (CIE L*a*b* system). We recorded reflectance using wavelengths of white light ranges (380-780 nm). We used differential scanning calorimetry technique for thermal properties. The results indicate the Trehalose fibers had a melting temperature of 192.8°C and exhibited less change in colour and reflectance compared to the others. The PEG4000 fibers had a melting temperature at 59.3°C. Trehalose had higher thermal properties compared to PEG4000. Thus, Trehalose is an appropriate conservation material for ropes and other fiber-based materials that are stored or displayed in environments with high humidity and temperature, such as the case in Thailand. Keywords Phanom-Surin Shipwreck, conservation of rope (fiber), Trehalose, PEG4000 List of Figure Figure 1 The twisted fiber used for tie Torpedo jars Figure 2. Untreated fiber. a) Cross-sectional, b) Cross-sectional lumen, c) Longitudinal Figure 3. PEG4000 fiber. (a) Cross-sectional, (b) Cross-sectional lumen, (c) Longitudinal Figure 4. Trehalose fiber. (a) Cross-sectional, (b) Cross-sectional lumen, (c) Longitudinal Figure 5. Fresh sugar palm fiber. (a) Cross-sectional, (b) Cross-sectional lumen, (c) Longitudinal Figure 6. Twisted rope. (a) Untreated rope, (b) Trehalose-treated rope, (c) PEG4000-treated rope Figure 7. Graph of reflectance comparison results between untreated fiber, Trehalose fiber, and PEG4000 fiber. Figure 8. DSC thermogram of untreated fibers (a), pure Trehalose (b), pure PEG4000 (c), Trehalose fibers (d), and PEG4000 fibers (e): 1st Heating. 3 5 5 5 6 6 6 8 List of Table Table 1 shows the results of the L*a*b* colour space data for untreated rope, rope treated with Trehalose, and rope treated with PEG4000 7 1 �1. INTRODUCTION The Phanom-Surin shipwreck was discovered at Samut Sakhon, Thailand in September 2013. The shipwreck is dated to the 9th century CE (1stROFAD 2016). We narrow our discussion to the excavated rope fibers. Our literature review on rope fiber or “Tao” fibers identified them as Arenga pinnata, commonly known as the sugar palm or Arenga palm (Mahaphol 2013). For centuries sugar palm fibers were used as ropes for ships due to their exceptional strength, durability, and resistance to saltwater (Ishak et al. 2012, 700). Our study expands from this literature review to focus on the conservation of twisted rope/fiber, used to tie Torpedo jars (Figure 2), with a specific emphasis on museum exhibition and storage purposes. In this study, we compared conservation of fresh sugar palm fibers in PEG4000 and Trehalose, which demonstrated superior properties compared to the non-treated fibers. We examined moisture absorption, which the fibers treated with Trehalose (henceforth Trehalose fiber) showed lower moisture absorption than the fibers treated with PEG4000 (henceforth PEG4000 fiber). We compare the physical characteristics of the fibers that underwent conservation treatment (in either PEG4000 or Trehalose) by the changes in reflectance, colour and heat resistance. Our results are intended for use to design a conservation plan for the appropriate environment for museum display, storage, and conservation. Figure 1 The twisted fiber used to tie Torpedo jars 2. MATERIALS AND METHODS 2.1 Materials On the Phanom-Surin shipwreck ropes were used to tie Torpedo jars. PEG4000 (M w ≈ 3500 - 4000) was purchased from Loba ChemieTM, India. Trehalose (TREHA®) was purchased from Hayashibara Co.Ltd., Japan. 2.2 Samples preparation We prepared the fiber samples by flushing with deionized water until the electrical conductivity (EC) of the solution was below 100 μS. The fibers were divided into three groups, dry at room temperature, soaked with Trehalose or PEG4000. We tightly covered the fibers while soaking to prevent water evaporation. i. ii. Untreated - The untreated fibers were dried at room temperature. Soaked with Trehalose - The fibers were immersed in Trehalose starting with 20 percent brix at room temperature (34°C). The solution was heated, while the Trehalose concentration increased from 40 percent to 60 percent brix. The controlled temperature did not exceed 80°C, and the fibers were immersed for 24 hours. Once the fibers reached the (20, 40, 60) percent brix constants the fibers were dried with an electric-fan until completely dried. The fibers were cleaned with warm water to remove any residual Trehalose and dried until a constant weight is obtained. 2 �iii. 2.3 Soaked with PEG4000 - The immersion process in PEG4000 follows the same procedure as immersion in the Trehalose solution, but the fibers were left to dry at room temperature. Scanning electron microscopy (SEM) After sample preparation (see above for details) all fibers were immersed in liquid nitrogen, broken up and stored in a desiccator to absorb moisture for one day. Each were coated with gold (Au-Coating) through an auto fine coater (Smart Coater, DII-29030SCTR) for 4 minutes. Analysis was conducted with a benchtop scanning electron microscope (JCM-7000, JEOL) at 5 kilovolts (kV). 2.4 Differential Scanning Calorimetry (DSC) After sample preparation and SEM all fibers underwent thermal analysis with the Differential Scanning Calorimetry (DSC) technique (Mettler Toledo brand). Five milligrams (mg) of sample were sealed hermetically in the aluminium crucible. Nitrogen gas was purged at a flow rate of 20 millilitres per minute (mL/min). At a heating rate of 10 °C/min across a range from -20 to 200°C to 50 to 230°C. 2.5 Spectroradiometer After sample preparation, SEM and DSC all fibers underwent spectroradiometer (Konica Minolta CS2000), with wavelengths from 380 to 780 nanometers (nm) range. The samples were prepared by twining and thickening the ropes, three random points were selected for spectroradiometer at a 0.2 aperture in the (CIELAB) (Commission Internationale de l´Eclairage, L*, a* and b* represent each of the three values the CIELAB color space uses to measure objective color and calculate color differences. L* represents lightness from black to white on a scale of zero to 100, while a* and b* represent chromaticity with no specific numeric limits. Negative a* corresponds with green, positive a* corresponds with red, negative b* corresponds with blue and positive b* corresponds with yellow). Under the International Commission on Illumination (CIE) commonly used D65 - D series of illuminants portray standard illumination conditions at open-air in different parts of the world measurements were taken and the reflectance values were averaged. The data was then analyzed for colour variability. 3. RESULTS AND DISCUSSION Our study focuses on the conservation of waterlogged fiber in Trehalose and PEG4000 that was used to tie Torpedo jars in the Phanom-Surin shipwreck (Figure 2), for the purpose of museum exhibition and storage. 3.1 Scanning Electron Microscopy Microscopic examinations of fibers treated with Trehalose and PEG4000 show structural differences compared to untreated rope samples. Untreated rope displayed severe degradation, collapse of cells, and the longitudinal section had a hole where the silica had come off (Figure 4-c). Fresh sugar palm fibers retain silica (Figure 7-c). Cross-sections of PEG4000-treated and Trehalose-treated ropes appeared similar to each other. PEG4000-treated rope had a smoother longitudinal surface (Figure 5c), while Trehalose-treated rope exhibited an orthorhombic crystal form (Figure 6-c). These differences indicate distinct effects of the different immersive treatments of conserved fibers. Trehalose and PEG4000 conserved fibers of twisted rope show surface cracks due to SEM sample preparation. The micrograph of these twisted fibers (Figure 8) show reduced bend and twist resistance. Specifically, Trehalose exhibits lower twist resistance than PEG4000. In previous research the conserved fibers improved tensile strength (Mahaphol 2013). Trehalose, with its rigid crystalline structure, demonstrates higher tensile strength than PEG4000 and untreated rope. 3 �Silica Body (a) (b) Hole of Silica Body (c) Figure 2. Untreated fiber. a) Cross-sectional, b) Cross-sectional lumen, c) Longitudinal (a) (b) (c) Figure 3. PEG4000 fiber. (a) Cross-sectional, (b) Cross-sectional lumen, (c) Longitudinal (a) (b) (c) Figure 4. Trehalose fiber. (a) Cross-sectional, (b) Cross-sectional lumen, (c) Longitudinal Silica Body (a) (b) (c) Figure 5. Fresh sugar palm fiber. (a) Cross-sectional, (b) Cross-sectional lumen, (c) Longitudinal (a) (b) (c) Figure 6. Twisted rope. (a) Untreated rope, (b) Trehalose-treated rope, (c) PEG4000-treated rope 4 �3.2 Reflectance (percent) Figure 7. Graph of reflectance comparison results between untreated fiber, Trehalose fiber, and PEG4000 fiber. The results of the reflectance (percent) measurements indicate that both PEG4000 and Trehalose conserved fibers increased reflectance compared to the non-treated fiber. Pointedly, the PEG4000 fiber exhibited higher reflectance percentage than the Trehalose fiber. This suggests that PEG4000 treatment may have more significant impact on enhancing the fiber's reflective properties. PEG4000 fiber (Figure 5-c) surfaces were coated with a layer of silica so the longitudinal surface reflection was smoother and more uniform, which resulted in regular reflection of incident light. In contrast, the Trehalose fiber (Figure 6-c) have rough surfaces with irregularly shaped rectangular features and thickness varies, which leads to scattered reflection of incident light. The diffused light in multiple directions is disordered and does not exhibit regular reflection. This causes a decrease in the detected signal. 3.3 Colour measurement ΔE* Table 1 shows the results of the L*a*b* colour space data for untreated fiber, Trehalose fiber, and PEG4000 fiber. L* ± SD a* ± SD b* ± SD ΔE* No-treatment (PSF ) 14.17±2.20 0.66±0.21 2.20±0.23 - PSF/PEG4000 15.85±3.05 0.56±0.77 1.03±0.44 2.05 PSF/Trehalose 14.12±4.49 0.98±0.53 2.03±0.98 0.37 No-treatment (Currently) 23.53±4.59 1.89±0.60 7.33±0.45 10.74 Treatment a Note: a PSF refers to Phanom-Surin fiber The untreated fiber has a low L* value of 14.17, indicating a relatively dark colour. The positive a* value of 0.66 and positive b* value of 2.20 suggests the colour of the untreated fiber has a slightly reddish-yellow hue. The PEG4000 fiber increased the L* value to 15.85, indicating a brighter colour. The a* value decreased slightly to 0.56, indicating a slightly greener hue, while the b* value decreased significantly to 1.03, indicating a more blueish hue. The Trehalose fiber resulted in a similar L* value as the untreated fiber at 14.12, but a higher positive a* value of 0.98 and a higher positive b* value of 2.03. This suggests that the Trehalose fiber colour has a more reddish-yellow hue than the untreated fiber. The CIE L*a*b* colour system allowed us to evaluate the colour change of the fiber. The colour difference (ΔE*) was calculated by comparing the colour values of the treated and non-treated fibers. ΔE* value greater than one was considered visually detectable. 5 �The results of the colour measurement ΔE* for PEG4000 fiber (2.05) and Trehalose fiber (0.37) (non-treated fiber so there is no ΔE* value) indicate that the addition of PEG4000 to the fiber caused a significant colour change, while Trehalose fiber minimally changed. These findings suggest that the Trehalose treatment more effectively preserves the colour stability of the sugar palm fiber than PEG4000. The cause of colour change requires further investigation. 3.4 Differential Scanning Calorimetry (DSC) Figure 8. DSC thermogram of untreated fibers (a), pure Trehalose (b), pure PEG4000 (c), Trehalose fibers (d), and PEG4000 fibers (e): 1st Heating. We investigated the thermal properties of fibers following preservation with Trehalose and PEG4000 treatment, which resulted in changes in the thermogram characteristics of the fibers. Figure 10 (a) and (d) show the relationship between Fiber and Fiber/Trehalose. DSC thermogram: peaks at 96.11°C and 139.73°C for Fiber, and 92.27°C and 149.44°C for Fiber/Trehalose. The first peak corresponds to water evaporation. Fiber/Trehalose has more easily evaporated water due to the attributed hydroxyl groups in the cellulose structure, which make it difficult to bond with water. The presence of a hydroxyl group of Trehalose in Fiber/Trehalose also binds to the cellulose of the fiber, causing a decrease in the amount of bonding between water and cellulose. At 149.44°C, the melting temperature (Tm) of Fiber or Fiber/Trehalose occurs. In fact, Trehalose's melting temperature is at 192.80°C, which causes the crystals of the Trehalose chain to fold into lamellae this absorbs heat energy from surroundings and causes vibrations until the intermolecular attraction is overcome. As a result, the crystals dissociate into randomly spaced Trehalose chain molecules. The second peak of Fiber/Trehalose (Figure 10 (b)) covers Trehalose's melting peak and has a wide range. The temperature transition from glassy state to rubbery state (T g) occurs at 106.50 °C, where Trehalose chains in the amorphous region absorb heat energy, which increase distance between chains and free up space for volume. Comparison of the DSC of Fiber and Fiber/Trehalose, Trehalose treatment raised the second peak temperature, this indicates higher melting temperature and improved high-temperature resistance. Figure 10 (a) and (c) show the relationship between Fiber and Fiber/ PEG4000. From and (c), the first peak observed at 54.36°C (Figure 10e) corresponds to the melting temperature (T m) of PEG4000. A lower melting point than Trehalose. PEG4000 is composed of repeated units of ethylene glycol, which 6 �enable it to form hydrogen bonds with water molecules. In comparison, Trehalose is composed of a cyclic glucose disaccharide that forms strong hydrogen bonds due to the two glucose molecules being linked by an α,α-1,1-glycosidic bond. These structures when compared result in Trehalose’s higher melting temperature than PEG4000. Based on the thermal investigation, Trehalose-treated rope showed superior thermal stability and less moisture absorption than PEG4000. 4. CONCLUSION We demonstrated the use of Trehalose and PEG4000 in the conservation of twisted fiber used to tie the torpedo jars on the Phanom-Surin shipwreck. The results showed the Trehalose fibers had less change in colour, reflectance and higher thermal properties compared to the PEG4000 fibers. We conclude Trehalose is an effective conservation material for fibers in high humidity and temperature environments. The use of Trehalose as a conservation treatment for sugar palm fibers created a barrier between the cellulose structure and water, which reduced the amount of water that can evaporate from the fibers. The experiments in this study are informative and favour Trehalose as the preferred fiber treatment for museum display and storage in high humidity and heat environments, such as Thailand. Acknowledgements The authors sincerely thank Mr.Sanae Mahaphol and Ms.Sopit Panyakhan, Scientists from conservation science division, and The Fine Arts Department of Thailand for their help and constant encouragement. Thanks Ms.Sirin Yuanyaidee, Director of Kanchanaphisek National Museum and staff. Thank you Assoc.Prof.Dr.Mantana Opaprakasit and Dr.Intatch Hongrattanavichit from Faculty of Science Chulalongkorn University for their support with the analysis instruments and their advice. Moreover, we’re grateful to the Sumitomo Foundation, Japan and Ms.Umaporn Kruekamwang, Director of Office of National Science Museum Thailand for the support. Bibliography Ishak, M.R., S.M. Sapuan, Z. Leman, M.Z.A. Rahman, U.M.K Anwar, and J.P. Siregar. "Sugar palm (Arenga pinnata): Its fibres, polymers and composites." ELSEVIER (2012): 700. Mahaphol, Saneh. "The conservation of ropes from the Phanom-Surin Shipwreck Site, Thailand." Academia (2013): 1-16. The 1st Regional Office of Fine Arts Department, Ratchaburi Fine Arts Department (1stROFRD). Study of Phanom-Surin Shipwreck, Phanthai Norasing Sub-district, Meuang District, Samut Sakhon Province (2013-2015). Bangkok: Bangkok in House, co., 2016. 7 �8 � Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource 2023 Session 14: Conservation Treatment of Underwater Cultural Heritage Subject The topic of the resource Session 14 papers Description An account of the resource Papers presented at Session 14 of the 2023 Asia Pacific Regional Conference on Underwater Cultural Heritage Creator An entity primarily responsible for making the resource Asia Pacific Regional Conference on Underwater Cultural Heritage Publisher An entity responsible for making the resource available The Museum of Underwater Archaeology Date A point or period of time associated with an event in the lifecycle of the resource November 2023 Rights Information about rights held in and over the resource Asia Pacific Regional Conference on Underwater Cultural Heritage Language A language of the resource English Rights Holder A person or organization owning or managing rights over the resource. Asia Pacific Regional Conference on Underwater Cultural Heritage Document A resource containing textual data. Note that facsimiles or images of texts are still of the genre text. Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Conserving Ropes from the Phanom-Surin Shipwreck in Thailand: Case Study on Storage and Exhibition at the National Museum of Thailand Description An account of the resource There are several important factors to consider when studying appropriate conservation methods for fibers in museum exhibitions or storage. This research focused on investigating the potential of using Trehalose and polyethylene glycol 4000 (PEG4000) as treatments for shipwreck rope fibers in Thailand's museums. The efficacy of these treatments was evaluated by using a twisted fiber thread to tie the torpedo jar. The initial desalinated fibers were subjected to three groups: untreated rope was dried at room temperature, ropes conserved with Trehalose, and ropes conserved with PEG4000. Identical concentrations of both the Trehalose and PEG4000 solutions started at a concentration of 25 percent brix then increased progressively to 40 percent and 60 percent brix. We employed four different analyses. We used scanning electron microscopy to study morphological properties. Prior to treatment and after treatment we compared numerical evaluation of the colour change using ΔE* values (CIE L*a*b* system). We recorded reflectance using wavelengths of white light ranges (380-780 nm). We used differential scanning calorimetry technique for thermal properties. The results indicate the Trehalose fibers had a melting temperature of 192.8°C and exhibited less change in colour and reflectance compared to the others. The PEG4000 fibers had a melting temperature at 59.3°C. Trehalose had higher thermal properties compared to PEG4000. Thus, Trehalose is an appropriate conservation material for ropes and other fiber-based materials that are stored or displayed in environments with high humidity and temperature, such as the case in Thailand. Creator An entity primarily responsible for making the resource Natchaya Pattanasuttirat Kunthida Chimma Puangporn Srisomboon Monchalus Pitisinchoochai Publisher An entity responsible for making the resource available The Museum of Underwater Archaeology Date A point or period of time associated with an event in the lifecycle of the resource 2023 Language A language of the resource English Bibliographic Citation A bibliographic reference for the resource. Recommended practice is to include sufficient bibliographic detail to identify the resource as unambiguously as possible. Pattanasuttirata, Natchaya, Kunthida Chimmab, Puangporn Srisomboon, and Monchalus Pitisinchoochai. 2023. “Conserving Ropes from the Phanom-Surin Shipwreck in Thailand: Case Study on Storage and Exhibition at the National Museum of Thailand.” Edited by Jennifer Craig, Jay Mok and T. Kurt Knoerl. In Proceedings of Fifth Asia Pacific Regional Conference on Underwater Cultural Heritage: Gwangju, The Republic of Korea, November 13-18 2023. The Museum of Underwater Archaeology. URL: https://apconf.omeka.net/exhibits/show/apconfproceedings/item/1908 Asia-Pac Session 14 2023