- Email: [email protected]
An attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic study of waterlogged woods treated with melamine formaldehyde
Journal Pre-proof An Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) Spectroscopic Study of Waterlogged Woods Treated with Melamine Formaldehyde Namık kilic¸, A. G¨okc¸e kilic¸
PII:
S0924-2031(19)30224-3
DOI:
https://doi.org/10.1016/j.vibspec.2019.102985
Reference:
VIBSPE 102985
To appear in:
Vibrational Spectroscopy
Received Date:
12 September 2019
Revised Date:
13 October 2019
Accepted Date:
23 October 2019
Please cite this article as: kilic¸ N, kilic¸ AG, An Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) Spectroscopic Study of Waterlogged Woods Treated with Melamine Formaldehyde, Vibrational Spectroscopy (2019), doi: https://doi.org/10.1016/j.vibspec.2019.102985
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier.
An Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) Spectroscopic Study of Waterlogged Woods Treated with Melamine Formaldehyde Namık KILIÇ1, A. Gökçe KILIÇ2 1
Istanbul University Faculty of Letters Department of Conservation of Marine Archaeological Objects, Laleli – İstanbul, Turkey 2 Istanbul University Faculty of Letters Museology Department, Vezneciler– İstanbul, Turkey
Corresponding author: A. Gökçe KILIÇ ([email protected])
re
-p
ro of
Abstract Various different methods are used for the conservation of waterlogged wood. One of them is melamine formaldehyde method which is also used for conservation of highly degraded woods of the Yenikapı shipwrecks. In this method, melamine formaldehyde resin is replaced with the water inside the waterlogged wood. After impregnation and drying process, the wood turns into a stable state. In order to sustain a successful conservation procedure, the wood should be impregnated with the resin. Otherwise, shrinkage and collapse of the wood occur in the parts which are not impregnated with the resin. In this study, 20 melamine formaldehyde treated core samples, which were taken from Yenikapı shipwrecks, were analysed with FTIR-ATR to determine the success of the impregnation. To determine significant bands which are related to melamine formaldehyde, spectra of fresh wood, waterlogged wood, and melamine formaldehyde treated wood were analysed considering wood species. On the spectra of melamine formaldehyde treated woods, the band at ~ 810 cm-1 was determined which is formed due to the presence of triazine. With this gained information, FTIR analyses were done on the wood samples which were in the impregnation boxes. The band at ~ 810 cm-1 was determined on the spectra of these samples. It shows that woods were impregnated with melamine formaldehyde and they can be dried in order to end the process.
Introduction
na
1.
lP
Keywords: Waterlogged wood, conservation, ATR-FTIR, melamine formaldehyde.
Jo
ur
Conservation of wooden shipwrecks, which is one of the important elements of the underwater cultural heritage, requires special expertise. These cultural heritages can be transferred to future generations with proper conservation techniques. Therefore, all steps of the process should be considered carefully for a successful conservation process. The marine environment can be a preventive environment for the archaeological woods. Rapid burial in anoxic environment followed by the complete burial are the necessary factors for good preservation of the archaeological wood. The wood degrades very slowly in these circumstances compared to wood degradation above ground. Especially, archaeological woods can be preserved better in environments with limited biological activity. On the other hand, the waterlogged woods can become degraded due to long contact with the burial environment [1-4]. The wood is formed from cellulose, hemicellulose, and lignin. The loss of the carbohydrate components of the wood causes the degradation of waterlogged wood. The lignin is almost unchanged while less stable polysaccharides such as cellulose and hemicellulose are degraded [5]. As a result and also cause of the degradation, the wood fills with water. The uncontrolled removal of water from the waterlogged wood causes irreversible degradation of the wood. For preventing waterlogged wood from collapse and shrinkage when the object is dried, several conservation methods have been applied for years [6-7]. The conservation methods of the waterlogged wood have been divided into three main categories: the first one is controlled drying, the second method
Jo
ur
na
lP
re
-p
ro of
is replacing the water in the wood with a consolidant, and the third method is freeze-drying. The conservation process should be a combination of assessment of the waterlogged wood, availability of the technical conservation methods, and resources and also the possibility of display or storage conditions. In addition, aesthetic, ethical, health, and environmental aspects should be taken into consideration while choosing a conservation method [8-9]. The conservation methods which are based on impregnation with a consolidation chemical are polyethylene glycol (PEG), sugar (sucrose, mannitol, sorbitol, lactitol), and melamine formaldehyde in general. Each method has its own advantages and disadvantages and when deciding the conservation method, many different parameters are taken into consideration. The biggest medieval shipwrecks collection in the world, which are dated from 5th to 11th centuries AD, was uncovered by the salvage excavations under the supervision of the Istanbul Archaeology Museums Directorate at Yenikapı in Istanbul. The conservation work on 31 of these 37 shipwrecks has been implemented by the Istanbul University’s Department of Conservation of Marine Archaeological Objects [10-13]. In Yenikapı Shipwrecks Project, main conservation technique is PEG pre-impregnation followed by freeze-drying method. On the other hand, some wooden parts of the shipwrecks are treated with melamine formaldehyde method [14]. To determine the conservation method of the waterlogged woods, it is very crucial to identify the degradation degree of the waterlogged wood. The age of the wood, wood species, intended use of the wood, the ambient conditions under which it is buried and the time it spends under these conditions affect the degradation degree of the waterlogged wood [15-16]. In order to determine the degradation degree of the waterlogged woods of the Yenikapı shipwrecks, maximum water content (MWC) and basic density (g/cm3) measurements are often used [17]. Wood with maximum water content and low density is classified as highly degraded wood. Some woods of the Yenikapı shipwrecks are highly degraded. These woods are very soft and vulnerable. For instance, some of them were lifted from the excavation site by epoxy support due to their conditions. The highly degraded woods of the Yenikapı shipwrecks are treated with melamine formaldehyde method. This method has been developed in Germany and shipwrecks in Roman-Germanic Central Museum (RGZM) were treated with this method. In this method, impregnation is carried out with a water-soluble low molecular mass (400 to 700 g /mol) melamine formaldehyde polymer. The resin has low viscosity (150-200 m Pa.s), and small size of molecules (1 melamine molecule = 5 Ångström) (Figure 1). Impregnation takes place at room temperature and the impregnation time can take from a few weeks to one year depending upon the thickness and the degradation degree of the wood. After impregnation, woods are dried in an oven at 50⁰C for the poly-condensation of melamine formaldehyde for 7 to 14 days. In the melamine formaldehyde method, treatment time takes short, objects are light in weight, and surface details can be seen after the treatment. Despite the good chemical stability of melamineformaldehyde, cross-linkage of the resin is irreversible. With the knowledge of previous treatments of archaeological wood, it is accepted that conservation material should be removable. However, practice is usually more complicated than theory for the large scale of waterlogged wooden objects. In Yenikapı Shipwrecks Project, melamine formaldehyde method was used for conservation of highly degraded woods which can become exhausted during the treatment phase in other methods [9, 1819].
Figure 1. Chemical formulas of melamine and formaldehyde [20].
Materials and methods
Jo
2.
ur
na
lP
re
-p
ro of
For conservation of the highly degraded woods of the Yenikapı shipwrecks, the initial concentration of the melamine formaldehyde solution is 25%. In this method, triethylene glycol was added to the melamine formaldehyde solution in order to obtain a more flexible structure for the wood. Triethanolamine was added to the solution as an alkaline buffer to prolong the life of the solution. Urea is added to the solutions in order to decrease the effects of free formaldehyde which is very hazardous for human health. Urea also decreases the viscosity of the solution, thus increases the ability of the solution to be penetrated into the wood. Moreover, oxygen, carbon dioxide, acidity, and temperature have impacts on the impregnation and curing process of the resin. It is very difficult to remove the cured polymer from the surfaces of the wood. Therefore, the solution must be monitored systematically during the impregnation. To monitor the solution, the turbidity (cloudiness) of the solution and pH must be controlled periodically. To control the turbidity of the solution, the solution was dropped into distilled water. When turbidity occurs with this method, the wood is taken out of the solution. Turbidity is related to a decrease of the acidity level of the solution. Besides, the pH of the solution measured periodically. The pH of the solution is measured between 6.8 and 7.4 when the turbidity is seen [21-24]. In addition, determination of the full impregnation of the conservation chemical into the wood is very important to avoid any problem after drying process. In order to determine the impregnation of the melamine formaldehyde polymer into the wood, Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATRFTIR) technique was used in this study. FTIR is a powerful nondestructive material identification method, which is used in polymer chemistry in general and FTIR is frequently used in the analysing of the waterlogged wood. In addition, the use of the attenuated total reflection (ATR) attachment allows direct measurements from solid samples such as woods [25-26]. The changes in the chemical structure of the waterlogged wood are examined by FTIR method and also the penetration levels of the conservation chemicals, which are impregnated into the wood during the conservation process, can be examined with this technique [27-30]. In this study, FTIR analyses were performed on the wood samples, which were treated with melamine formaldehyde in order to determine the success of the penetration of the related chemical into the woods.
2.1.
Sampling
2.1.1. Melamine formaldehyde treated woods The study was done on 20 woods which were treated with melamine formaldehyde. The samples were taken from 3 shipwrecks (Figure 2). To determine the full impregnation of the melamine formaldehyde into the wood, core samples were taken from woods of the shipwrecks. All core samples were taken from dried woods which were treated with melamine formaldehyde. Melamine formaldehyde solution was used in 25% concentration after the desalination process had been completed. The woods were impregnated with melamine formaldehyde solution and dried in
re
-p
ro of
an oven at 50⁰C. Melamine formaldehyde solution was prepared with the following composition: Triethylene glycol at a ratio of 10% (w/w), triethanolamine at a ratio of 5% (w/w), and urea at a ratio of 5% (w/w) was added to the melamine formaldehyde solution.
Figure 2. Photos of the shipwrecks (IU Yenikapı Shipwrecks Project Archive).
ur
na
lP
17 wood samples which were taken from plane wood were analysed. 2 wood samples which were taken from pine wood were analysed. 1 chestnut wood sample were analysed. Prior to impregnation process of melamine formaldehyde, the maximum water content of the waterlogged woods was calculated in order to characterize the degradation of the waterlogged wood. This suggests that the woods were highly degraded. Detailed information of the samples is listed in Table 1.
Table 1. Detailed Information of the melamine formaldehyde treated wood samples. Sample
Jo
YK 3-D4 YK 3-D5 YK 3-D7 YK 3-D9 YK 3-D11 YK 3-D14/4 YK 3-D16 YK 3-D23 YK 3-OM6
Species* Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.)
MWC (%) 1221 1308 1105 1296 1046 983 1088 1140 1090
YK 3-OM13 YK 3-OM14 YK 16-E18 YK 16-E20 YK 36-E11 YK 36-E13 YK 36-E15 YK 36-E17 YK 36-E18 YK 36-TP1 YK 36-TP3
Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Chestnut (Castanea L.) Plane (Platanus L.) Pine (Pinus L.) Pine (Pinus L.)
1023 1047 1392 1467 765 827 870 580 756 520 567
2.1.2
ro of
Key to symbols E, D: Frame, OM: Keel, TP: Unidentified. The wood samples impregnated with melamine formaldehyde (but not dried)
lP
Table 2. Detailed Information of the samples.
Species*
Sample 1 Sample 2 Sample 3
Oak (Quercus L.) Oak (Quercus L.) Oak (Quercus L.)
na
Sample
2.1.3.
re
-p
Three core samples were taken from the woods which were found in Yenikapı (Table 2). These woods were taken from the impregnation boxes. The woods have been impregnated with melamine formaldehyde for around four months. These samples were taken to determine the success of the impregnation before the drying process.
MWC (%) 750 845 837
Fresh wood samples
Jo
ur
In order to compare the spectrum of melamine formaldehyde treated wood to spectrum of the fresh wood sample, fresh plane, pine, oak, and chestnut wood samples were taken for FTIR analyses. Fresh wood samples were dried in an oven before performing FTIR analysis. 2.1.4.
Waterlogged wood samples
In order to compare the spectrum of melamine formaldehyde treated wood to spectrum of the waterlogged wood sample, plane, pine, oak, and chestnut waterlogged wood samples were taken for FTIR analyses. Waterlogged wood samples were dried in an oven before performing FTIR analysis. *
Species identification of the woods was carried out by Prof. Dr. Ünal Akkemik, Istanbul University Cerrahpaşa’s Faculty of Forestry [31].
2.2.
FTIR Analyses
FTIR spectroscopy was carried out on a Perkin Elmer Spectrum One series FTIR spectrometer using an ATR sampling accessory. The study was performed on archaeological material therefore ATR sampling accessory was used to analyse very small samples. All the spectra were acquired (16 scans/sample) in the range of 4000 – 600 cm-1 at a Fourier transform (FT) resolution 4 cm-1 and subsequently had a ratio against a 16-scan open-beam background spectrum to produce absorbance. The FTIR spectra of the wood samples were baseline corrected in Spectrum One. The spectra were recorded as absorbance versus wavenumber. 3.
Results and Discussion
Jo
ur
na
lP
re
-p
ro of
Melamine formaldehyde method is used for the highly degraded woods of the Yenikapı shipwrecks. When Table 1 is examined, it is seen that the maximum water content in the wood samples ranged between 500% and 1400% and the most degraded samples are plane wood. Therefore, most of the samples are also plane wood. Firstly, the spectra of melamine formaldehyde treated wood sample were compared with the spectra of fresh wood and waterlogged wood for the detection of peaks that are not present in the natural structure of wood. In order to make a healthy comparison, the spectra of the same wood species were compared. The species of the wood samples, which were analysed in this study, are plane, pine, oak, and chestnut woods. Seventeen plane wood samples, which were treated with melamine formaldehyde, were analysed in this study. Firstly, the FTIR spectra of fresh plane wood, waterlogged plane wood, and wood treated with melamine formaldehyde were analysed (Figure 3).
Figure 3. The FTIR spectra of fresh plane wood, waterlogged plane wood, and wood treated with melamine formaldehyde (MF). In this study, two pine wood samples which were treated with melamine formaldehyde, were analysed. Therefore, the FTIR spectra of fresh pine wood, waterlogged pine wood, and wood treated with melamine formaldehyde (MF) were analysed (Figure 4).
ro of
-p
Figure 4. The FTIR spectra of fresh pine wood, waterlogged pine wood, and wood treated with melamine formaldehyde (MF).
Jo
ur
na
lP
re
In this study, one chestnut wood, which was treated with melamine formaldehyde, was analysed. Therefore, the FTIR spectra of fresh chestnut wood, waterlogged chestnut wood, and wood treated with melamine formaldehyde (MF) were presented in Figure 5.
Figure 5. The FTIR spectra of fresh chestnut wood, waterlogged chestnut wood, and wood treated with melamine formaldehyde (MF).
When all the spectra are examined, it is seen that peaks are concentrated especially in 1800800 cm region. On the other hand, this wavelength range gives information about the changes of cellulose, hemicellulose and lignin components in the structure of the waterlogged wood [32]. In addition, a new peak at ~813 cm-1 (the peaks are shown on the spectra as A with dotted line) can be identified on spectra of treated woods in Figure 3, 4, and 5. The band at ~ 810 cm-1 was determined which is formed due to the presence of triazine [20]. It was understood that it is the distinctive band on the spectra of melamine formaldehyde treated woods in order to determine the impregnation. Absorbance spectra of the 20 samples, which were treated with the melamine formaldehyde, were presented in Figure 6. In order to determine the impregnation of the melamine formaldehyde into the woods, the spectra were examined in the range of 700-900 cm-1. A strong peak at 813 cm-1 (the peaks are shown on the spectra as A with dotted line) can be observed in all spectra.
na
lP
re
-p
ro of
-1
Figure 6. The FTIR spectra of wood samples which were treated with melamine formaldehyde.
Jo
ur
FTIR spectra of melamine formaldehyde were studied by Merline et al and Cesar et al in detail. When changes of the FTIR bands during polymerization were analysed in these studies, it was obtained that the bands, except the band at ~ 810 cm-1, were very similar to the bands of the woods. The band at ~ 810 cm-1 is related to bending vibration of triazine. Formation of this band in the spectra of the core wood samples, which were treated with melamine formaldehyde, reveals that the polymer impregnated into the wood. Moreover, it is understood that the melamine has reacted to methylol groups and there is no residual melamine and formaldehyde remains with formation of this band [20-33]. In addition, FTIR analyses were done on the samples, which were impregnated but not dried in the oven in order to determine the success of the impregnation of the resin. Three core samples were analysed with the FTIR method and spectra were examined (Figure 7). These samples were taken from oak wood. Therefore, the FTIR spectra of fresh oak wood, waterlogged oak wood, and wood treated with melamine formaldehyde (MF) were examined. A strong peak at 813 cm-1 (the peaks are shown on the spectra as A with dotted line) can be observed in all spectra. It shows that resin impregnated into wood.
ro of -p
Figure 7. The FTIR spectra of wood samples, waterlogged oak wood, and fresh oak wood.
Conclusion
lP
4.
re
The strong peak at 813 cm-1 (the peaks are shown on the spectra as A with dotted line), which is formed due to the presence of triazine, can be observed in all spectra. It shows that resin impregnated into wood and then wood samples can be dried.
Jo
ur
na
Although more than 50 years have passed since melamine formaldehyde method was developed for conservation of waterlogged wood, several numbers of studies on chemical analyses of the method were not done. Even if the method is irreversible and therefore it is problematic for the conservators, it can be used for the conservation of the highly degraded waterlogged archaeological woods. There are many steps of a successful conservation process and the success of these steps must be followed by conservators. In conservation methods with replacing the water in the wood with a consolidant, it is crucial to determine the impregnation of the consolidant into the wood. In Yenikapı Shipwrecks Project, melamine formaldehyde method is used for conservation of highly degraded wood. The removal of the cured polymer from the surface of the wood is very difficult and can damage the wood. Therefore, the impregnation process is followed very carefully. The melamine formaldehyde solution during the impregnation process should be monitored. Controlling of the pH and the turbidity of the solution provide preventing of the accumulation of the cured polymer in the surface of the wood. On the other hand, impregnation of the resin into the thick woods before the decreasing of the pH value of the solution should also be checked. In order to determine the success of the impregnation of the resin into the wood, FTIR analyses were performed on melamine formaldehyde treated dried woods. Firstly, melamine formaldehyde treated samples were divided into group by wood species. Four different species of wood were analysed in this study. To examine the spectra of the melamine formaldehyde treated wood samples, spectra of fresh wood, waterlogged wood, and treated wood were compared considering the wood species. With analysing the spectra of fresh wood, waterlogged wood, and treated wood, it was found that the formed bands were similar to each other except the band at ~ 810 cm-. This peak is not found in
the spectra of fresh wood or waterlogged wood. This band is related to bending vibration of triazine and formation of this band shows that wood is impregnated with melamine formaldehyde. After this determination, FTIR analyses were done on the wood samples which were taken from melamine formaldehyde solution box before the drying process to determine the impregnation. The bands at ~ 810 cm were observed in the spectra of these samples. It was found that these woods were impregnated with melamine formaldehyde successfully and they can be dried. On the other hand, the bands are formed during the curing of the melamine formaldehyde can not be detected easily because very similar bands were present on the spectra of wood.
Declaration of conflicting interests The Authors declares that there is no conflict of interest.
ro of
Acknowledgments
Jo
ur
na
lP
re
-p
We would like to acknowledge Prof. Dr. Ufuk Kocabaş, Istanbul Archaeology Museums, and Yenikapı Shipwrecks Project Team for their help and support. We thank Prof. Eleanor Schofield and The Mary Rose Trust for their permission to use of FTIR, and Scientific and Technological Research Council of Turkey (TUBITAK) for their support. The IU Yenikapı Shipwrecks Project has been realized with the financial support of İstanbul University Scientific Research Projects Unit (Project nos: 2294, 3907, 7381, 12765, SDK-2016-3777, SDK-2016- 3776).
References G. McConnachie, Air drying behaviour of waterlogged archaeological woods from the Tudor warship Mary Rose, Doctoral dissertation, University of Portsmouth (2005).
[2]
A. Maccotta, P. Fantazzini, C. Garavaglia, I. D. Donato, P. Perzia, M. Brai, F. Morreale, Preliminary 1H NMR study on archaeological waterlogged wood. Annali di Chimica: Journal of Analytical, Environmental and Cultural Heritage Chemistry, 95(3‐4), (2005) 117-124, https://doi.org/10.1002/adic.200590013.
[3]
M. P. Colombini, J. J. Lucejko, F. Modugno, M. Orlandi, E. L. Tolppa, L. Zoia, A multi-analytical study of degradation of lignin in archaeological waterlogged wood. Talanta, 80(1), (2009) 6170, https://doi.org/10.1016/j.talanta.2009.06.024.
[4]
C. G. Björdal, Microbial degradation of waterlogged archaeological wood. Journal of Cultural Heritage, 13(3), (2012) 118-122, https://doi.org/10.1016/j.culher.2012.02.003.
[5]
C. Capretti, N. Macchioni, B. Pizzo, G. Galotta, G. Giachi, D. Giampaola, The characterization of waterlogged archaeological wood: the three Roman ships found in Naples (Italy). Archaeometry, 50(5), (2008) 855-876, https://doi.org/10.1111/j.1475-4754.2007.00376.x.
[6]
R. J. Barbour, Treatments for waterlogged and dry archaeological wood. Archaeological wood, (1990) 177-192, https://doi.org/10.1021/ba-1990-0225.ch007.
[7]
M. Christensen, M. Frosch, P. Jensen, U. Schnell, Y. Shashoua, O. F. Nielsen, Waterlogged archaeological wood—chemical changes by conservation and degradation. Journal of Raman Spectroscopy, 37(10), (2006) 1171-1178, https://doi.org/10.1002/jrs.1589.
[8]
J. M. Coles, E. Heritage, Waterlogged wood: guidelines on the recording, sampling, conservation, and curation of structural wood (1990).
[9]
D. Gregory, P. Jensen, K. Strætkvern, Conservation and in situ preservation of wooden shipwrecks from marine environments. Journal of Cultural Heritage, 13(3), (2012) 139-148, https://doi.org/10.1016/j.culher.2012.03.005.
na
lP
re
-p
ro of
[1]
ur
[10] U. Kocabaş, Theodosius Limanı’nda Hayat, Batıklar ve Hızlı Bir Gömülme/Life at the Theodosian Harbour, Wrecks and A Rapis Silting. Yenikapı’nın Eski Gemileri/The Old Ships of the New Gate, Ed. U. Kocabaş, (2008) 23- 37.
Jo
[11] U. Kocabaş, Byzantine Shipwrecks at Yenikapı. Between Continents. Proceedings of the Twelfth Symposium on Boat and Ship Archaeology Istanbul 2009, Ed. N. Günsenin, (2012) 107114. [12] U. Kocabaş, Geçmişe Açılan Kapı Yenikapı Batıkları. Ege Yayınları, İstanbul (2015). [13] U. Kocabaş, The Yenikapı Byzantine‐Era Shipwrecks, Istanbul, Turkey: A preliminary report and inventory of the 27 wrecks studied by Istanbul University. International Journal of Nautical Archaeology. 44.1, (2015) 5-38, https://doi.org/10.1111/1095-9270.12084. [14] N. Kılıç, A. G. Kılıç, Conservation of Yenikapı Shipwrecks: From the Beginning to the Present. 14th ICOM-CC Wet Organic Archaeological Materials Working Group Conference, Portsmouth, UK, (2019) 70.
[15] J.I. Hedges, The Chemistry of Archaeological Wood. Archaeological Wood: Properties, Chemistry, and Preservation. Ed. R. J. Barbour, R. M. Rowell, American Chemical Society, Advences in Chemistry Series, 225, (1990) 111-140. [16] M. L. E. Florian, Scope and History of Archaeological Wood. Archaeological Wood: Properties, Chemistry, and Preservation. Ed. R. J. Barbour, R. M. Rowell, American Chemical Society, Advences in Chemistry Series, 225, (1990) 3-34. [17] N. Kılıç, A.G. Kılıç, Physical Properties for the Characterization of Waterlogged Archaeological Woods of Eight Yenikapı Shipwrecks from Byzantine Period. Mediterranean Archaeology and Archaeometry, Vol. 19, No 2, (2019) 133-148, https://doi.org/10.5281/zenodo.3364819. [18] M. Christensen, H. Kutzke, F. K. Hansen, New materials used for the consolidation of archaeological wood–past attempts, present struggles, and future requirements. Journal of Cultural Heritage, 13(3), (2012) 183-190, https://doi.org/10.1016/j.culher.2012.02.013.
ro of
[19] S. Collis, Revisiting Conservation Treatment Methodologies for Waterlogged Archaeological Wood: An Australian Study. AICCM Bulletin, 36(2), (2015) 88-96, https://doi.org/10.1080/10344233.2015.1111597.
-p
[20] D. J. Merline, S. Vukusic, A. A. Abdala, Melamine formaldehyde: curing studies and reaction mechanism. Polymer Journal, 45(4), (2013) 413, https://doi.org/10.1038/pj.2012.162.
re
[21] M. Wittköpper, Current development in the preservation of archaeological wet wood with melamine/amino resins at the Römisch – Germanisches Zentralmuseum. Archäologisches Korrespondenzblatt, 28, (1998) 637-64.
lP
[22] P. Hoffmann, M. Wittköpper, The Kauramin Method for Stabilizing Waterlogged Wood. Proceedings of the 7th ICOM-CC Working Group on Wet Organic Archaeological Materials Conference, Ed. C. Bonnot-Dicconne, X. Hiron, P. Hoffmann, (1999) 163-166. [23] N. Kılıç, A. G. Kılıç, Kauramin® Tests for Yenikapı Shipwrecks. 12th ICOM-CC Working Group on Wet Organic Archaeological Materials, Istanbul, (2013) 222-227.
na
[24] N. Kılıç, Conservation of a Group of Frames from YK 16 Shipwreck. Art-Sanat, (6), (2016) 85-97.
ur
[25] S. G. Kazarian, K. L. A. Chan, FTIR Imaging of Polymeric Materials. Polymer Morphology: Principles, Characterization, and Processing, (2016) 118-130, https://doi.org/10.1002/9781118892756.ch7.
Jo
[26] S. Akyüz, Investigation of the degradation stages of archaeological and historic silk textiles: An ATR-FTIR spectroscopic study. Archaeology Anthropology: Open Access, 3-1, (2018) 447-451, https://doi.org/10.31031/AAOA.2019.03.000573. [27] B. Pizzo, A. Alves, N. Macchioni, A. Alves, G. Giachi, M. Schwanninger, J. Rodrigues, Characterization of waterlogged wood by infrared spectroscopy. Proceedings of Wood Science for Conservation of Cultural Heritage, (2008) 5-7. [28] M. Broda, B. Mazela, K. Królikowska-Pataraja, C. A. Hill, The use of FT-IR and computed tomography non-destructive technique for waterlogged wood characterisation. Wood Res Slovakia, 5, (2015) 707-722.
[29] M. Traoré, J. Kaal, A. M. Cortizas, Application of FTIR spectroscopy to the characterization of archeological wood. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 153, (2016) 63-70, https://doi.org/10.1016/j.saa.2015.07.108. [30] E. McHale, C. C. Steindal, H. Kutzke, T. Benneche, S. E. Harding, In situ polymerisation of isoeugenol as a green consolidation method for waterlogged archaeological wood. Scientific Reports, 7, (2017) 46481, https://doi.org/10.1038/srep46481. [31] Ü. Akkemik, Woods of Yenikapi Shipwrecks. Ege Yayınları, Istanbul (2015). [32] C. Pozo, J. Díaz-Visurraga, D. Contreras, J. Freer, J. Rodríguez, Characterization of temporal biodegradation of radiata pine by Gloeophyllum trabeum through principal component analysis-based two-dimensional correlation FTIR spectroscopy. Journal of the Chilean Chemical Society, 61(2), (2016) 2878-2883. https://doi.org/10.4067/s071797072016000200006
Jo
ur
na
lP
re
-p
ro of
[33] T. Cesar, T. Danevčič, K. Kavkler, D. Stopar, Melamine polymerization in organic solutions and waterlogged archaeological wood studied by FTIR spectroscopy. Journal of Cultural Heritage, 23, (2017) 106-110, https://doi.org/10.1016/j.culher.2016.09.009.
PII:
S0924-2031(19)30224-3
DOI:
https://doi.org/10.1016/j.vibspec.2019.102985
Reference:
VIBSPE 102985
To appear in:
Vibrational Spectroscopy
Received Date:
12 September 2019
Revised Date:
13 October 2019
Accepted Date:
23 October 2019
Please cite this article as: kilic¸ N, kilic¸ AG, An Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) Spectroscopic Study of Waterlogged Woods Treated with Melamine Formaldehyde, Vibrational Spectroscopy (2019), doi: https://doi.org/10.1016/j.vibspec.2019.102985
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier.
An Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) Spectroscopic Study of Waterlogged Woods Treated with Melamine Formaldehyde Namık KILIÇ1, A. Gökçe KILIÇ2 1
Istanbul University Faculty of Letters Department of Conservation of Marine Archaeological Objects, Laleli – İstanbul, Turkey 2 Istanbul University Faculty of Letters Museology Department, Vezneciler– İstanbul, Turkey
Corresponding author: A. Gökçe KILIÇ ([email protected])
re
-p
ro of
Abstract Various different methods are used for the conservation of waterlogged wood. One of them is melamine formaldehyde method which is also used for conservation of highly degraded woods of the Yenikapı shipwrecks. In this method, melamine formaldehyde resin is replaced with the water inside the waterlogged wood. After impregnation and drying process, the wood turns into a stable state. In order to sustain a successful conservation procedure, the wood should be impregnated with the resin. Otherwise, shrinkage and collapse of the wood occur in the parts which are not impregnated with the resin. In this study, 20 melamine formaldehyde treated core samples, which were taken from Yenikapı shipwrecks, were analysed with FTIR-ATR to determine the success of the impregnation. To determine significant bands which are related to melamine formaldehyde, spectra of fresh wood, waterlogged wood, and melamine formaldehyde treated wood were analysed considering wood species. On the spectra of melamine formaldehyde treated woods, the band at ~ 810 cm-1 was determined which is formed due to the presence of triazine. With this gained information, FTIR analyses were done on the wood samples which were in the impregnation boxes. The band at ~ 810 cm-1 was determined on the spectra of these samples. It shows that woods were impregnated with melamine formaldehyde and they can be dried in order to end the process.
Introduction
na
1.
lP
Keywords: Waterlogged wood, conservation, ATR-FTIR, melamine formaldehyde.
Jo
ur
Conservation of wooden shipwrecks, which is one of the important elements of the underwater cultural heritage, requires special expertise. These cultural heritages can be transferred to future generations with proper conservation techniques. Therefore, all steps of the process should be considered carefully for a successful conservation process. The marine environment can be a preventive environment for the archaeological woods. Rapid burial in anoxic environment followed by the complete burial are the necessary factors for good preservation of the archaeological wood. The wood degrades very slowly in these circumstances compared to wood degradation above ground. Especially, archaeological woods can be preserved better in environments with limited biological activity. On the other hand, the waterlogged woods can become degraded due to long contact with the burial environment [1-4]. The wood is formed from cellulose, hemicellulose, and lignin. The loss of the carbohydrate components of the wood causes the degradation of waterlogged wood. The lignin is almost unchanged while less stable polysaccharides such as cellulose and hemicellulose are degraded [5]. As a result and also cause of the degradation, the wood fills with water. The uncontrolled removal of water from the waterlogged wood causes irreversible degradation of the wood. For preventing waterlogged wood from collapse and shrinkage when the object is dried, several conservation methods have been applied for years [6-7]. The conservation methods of the waterlogged wood have been divided into three main categories: the first one is controlled drying, the second method
Jo
ur
na
lP
re
-p
ro of
is replacing the water in the wood with a consolidant, and the third method is freeze-drying. The conservation process should be a combination of assessment of the waterlogged wood, availability of the technical conservation methods, and resources and also the possibility of display or storage conditions. In addition, aesthetic, ethical, health, and environmental aspects should be taken into consideration while choosing a conservation method [8-9]. The conservation methods which are based on impregnation with a consolidation chemical are polyethylene glycol (PEG), sugar (sucrose, mannitol, sorbitol, lactitol), and melamine formaldehyde in general. Each method has its own advantages and disadvantages and when deciding the conservation method, many different parameters are taken into consideration. The biggest medieval shipwrecks collection in the world, which are dated from 5th to 11th centuries AD, was uncovered by the salvage excavations under the supervision of the Istanbul Archaeology Museums Directorate at Yenikapı in Istanbul. The conservation work on 31 of these 37 shipwrecks has been implemented by the Istanbul University’s Department of Conservation of Marine Archaeological Objects [10-13]. In Yenikapı Shipwrecks Project, main conservation technique is PEG pre-impregnation followed by freeze-drying method. On the other hand, some wooden parts of the shipwrecks are treated with melamine formaldehyde method [14]. To determine the conservation method of the waterlogged woods, it is very crucial to identify the degradation degree of the waterlogged wood. The age of the wood, wood species, intended use of the wood, the ambient conditions under which it is buried and the time it spends under these conditions affect the degradation degree of the waterlogged wood [15-16]. In order to determine the degradation degree of the waterlogged woods of the Yenikapı shipwrecks, maximum water content (MWC) and basic density (g/cm3) measurements are often used [17]. Wood with maximum water content and low density is classified as highly degraded wood. Some woods of the Yenikapı shipwrecks are highly degraded. These woods are very soft and vulnerable. For instance, some of them were lifted from the excavation site by epoxy support due to their conditions. The highly degraded woods of the Yenikapı shipwrecks are treated with melamine formaldehyde method. This method has been developed in Germany and shipwrecks in Roman-Germanic Central Museum (RGZM) were treated with this method. In this method, impregnation is carried out with a water-soluble low molecular mass (400 to 700 g /mol) melamine formaldehyde polymer. The resin has low viscosity (150-200 m Pa.s), and small size of molecules (1 melamine molecule = 5 Ångström) (Figure 1). Impregnation takes place at room temperature and the impregnation time can take from a few weeks to one year depending upon the thickness and the degradation degree of the wood. After impregnation, woods are dried in an oven at 50⁰C for the poly-condensation of melamine formaldehyde for 7 to 14 days. In the melamine formaldehyde method, treatment time takes short, objects are light in weight, and surface details can be seen after the treatment. Despite the good chemical stability of melamineformaldehyde, cross-linkage of the resin is irreversible. With the knowledge of previous treatments of archaeological wood, it is accepted that conservation material should be removable. However, practice is usually more complicated than theory for the large scale of waterlogged wooden objects. In Yenikapı Shipwrecks Project, melamine formaldehyde method was used for conservation of highly degraded woods which can become exhausted during the treatment phase in other methods [9, 1819].
Figure 1. Chemical formulas of melamine and formaldehyde [20].
Materials and methods
Jo
2.
ur
na
lP
re
-p
ro of
For conservation of the highly degraded woods of the Yenikapı shipwrecks, the initial concentration of the melamine formaldehyde solution is 25%. In this method, triethylene glycol was added to the melamine formaldehyde solution in order to obtain a more flexible structure for the wood. Triethanolamine was added to the solution as an alkaline buffer to prolong the life of the solution. Urea is added to the solutions in order to decrease the effects of free formaldehyde which is very hazardous for human health. Urea also decreases the viscosity of the solution, thus increases the ability of the solution to be penetrated into the wood. Moreover, oxygen, carbon dioxide, acidity, and temperature have impacts on the impregnation and curing process of the resin. It is very difficult to remove the cured polymer from the surfaces of the wood. Therefore, the solution must be monitored systematically during the impregnation. To monitor the solution, the turbidity (cloudiness) of the solution and pH must be controlled periodically. To control the turbidity of the solution, the solution was dropped into distilled water. When turbidity occurs with this method, the wood is taken out of the solution. Turbidity is related to a decrease of the acidity level of the solution. Besides, the pH of the solution measured periodically. The pH of the solution is measured between 6.8 and 7.4 when the turbidity is seen [21-24]. In addition, determination of the full impregnation of the conservation chemical into the wood is very important to avoid any problem after drying process. In order to determine the impregnation of the melamine formaldehyde polymer into the wood, Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATRFTIR) technique was used in this study. FTIR is a powerful nondestructive material identification method, which is used in polymer chemistry in general and FTIR is frequently used in the analysing of the waterlogged wood. In addition, the use of the attenuated total reflection (ATR) attachment allows direct measurements from solid samples such as woods [25-26]. The changes in the chemical structure of the waterlogged wood are examined by FTIR method and also the penetration levels of the conservation chemicals, which are impregnated into the wood during the conservation process, can be examined with this technique [27-30]. In this study, FTIR analyses were performed on the wood samples, which were treated with melamine formaldehyde in order to determine the success of the penetration of the related chemical into the woods.
2.1.
Sampling
2.1.1. Melamine formaldehyde treated woods The study was done on 20 woods which were treated with melamine formaldehyde. The samples were taken from 3 shipwrecks (Figure 2). To determine the full impregnation of the melamine formaldehyde into the wood, core samples were taken from woods of the shipwrecks. All core samples were taken from dried woods which were treated with melamine formaldehyde. Melamine formaldehyde solution was used in 25% concentration after the desalination process had been completed. The woods were impregnated with melamine formaldehyde solution and dried in
re
-p
ro of
an oven at 50⁰C. Melamine formaldehyde solution was prepared with the following composition: Triethylene glycol at a ratio of 10% (w/w), triethanolamine at a ratio of 5% (w/w), and urea at a ratio of 5% (w/w) was added to the melamine formaldehyde solution.
Figure 2. Photos of the shipwrecks (IU Yenikapı Shipwrecks Project Archive).
ur
na
lP
17 wood samples which were taken from plane wood were analysed. 2 wood samples which were taken from pine wood were analysed. 1 chestnut wood sample were analysed. Prior to impregnation process of melamine formaldehyde, the maximum water content of the waterlogged woods was calculated in order to characterize the degradation of the waterlogged wood. This suggests that the woods were highly degraded. Detailed information of the samples is listed in Table 1.
Table 1. Detailed Information of the melamine formaldehyde treated wood samples. Sample
Jo
YK 3-D4 YK 3-D5 YK 3-D7 YK 3-D9 YK 3-D11 YK 3-D14/4 YK 3-D16 YK 3-D23 YK 3-OM6
Species* Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.)
MWC (%) 1221 1308 1105 1296 1046 983 1088 1140 1090
YK 3-OM13 YK 3-OM14 YK 16-E18 YK 16-E20 YK 36-E11 YK 36-E13 YK 36-E15 YK 36-E17 YK 36-E18 YK 36-TP1 YK 36-TP3
Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Plane (Platanus L.) Chestnut (Castanea L.) Plane (Platanus L.) Pine (Pinus L.) Pine (Pinus L.)
1023 1047 1392 1467 765 827 870 580 756 520 567
2.1.2
ro of
Key to symbols E, D: Frame, OM: Keel, TP: Unidentified. The wood samples impregnated with melamine formaldehyde (but not dried)
lP
Table 2. Detailed Information of the samples.
Species*
Sample 1 Sample 2 Sample 3
Oak (Quercus L.) Oak (Quercus L.) Oak (Quercus L.)
na
Sample
2.1.3.
re
-p
Three core samples were taken from the woods which were found in Yenikapı (Table 2). These woods were taken from the impregnation boxes. The woods have been impregnated with melamine formaldehyde for around four months. These samples were taken to determine the success of the impregnation before the drying process.
MWC (%) 750 845 837
Fresh wood samples
Jo
ur
In order to compare the spectrum of melamine formaldehyde treated wood to spectrum of the fresh wood sample, fresh plane, pine, oak, and chestnut wood samples were taken for FTIR analyses. Fresh wood samples were dried in an oven before performing FTIR analysis. 2.1.4.
Waterlogged wood samples
In order to compare the spectrum of melamine formaldehyde treated wood to spectrum of the waterlogged wood sample, plane, pine, oak, and chestnut waterlogged wood samples were taken for FTIR analyses. Waterlogged wood samples were dried in an oven before performing FTIR analysis. *
Species identification of the woods was carried out by Prof. Dr. Ünal Akkemik, Istanbul University Cerrahpaşa’s Faculty of Forestry [31].
2.2.
FTIR Analyses
FTIR spectroscopy was carried out on a Perkin Elmer Spectrum One series FTIR spectrometer using an ATR sampling accessory. The study was performed on archaeological material therefore ATR sampling accessory was used to analyse very small samples. All the spectra were acquired (16 scans/sample) in the range of 4000 – 600 cm-1 at a Fourier transform (FT) resolution 4 cm-1 and subsequently had a ratio against a 16-scan open-beam background spectrum to produce absorbance. The FTIR spectra of the wood samples were baseline corrected in Spectrum One. The spectra were recorded as absorbance versus wavenumber. 3.
Results and Discussion
Jo
ur
na
lP
re
-p
ro of
Melamine formaldehyde method is used for the highly degraded woods of the Yenikapı shipwrecks. When Table 1 is examined, it is seen that the maximum water content in the wood samples ranged between 500% and 1400% and the most degraded samples are plane wood. Therefore, most of the samples are also plane wood. Firstly, the spectra of melamine formaldehyde treated wood sample were compared with the spectra of fresh wood and waterlogged wood for the detection of peaks that are not present in the natural structure of wood. In order to make a healthy comparison, the spectra of the same wood species were compared. The species of the wood samples, which were analysed in this study, are plane, pine, oak, and chestnut woods. Seventeen plane wood samples, which were treated with melamine formaldehyde, were analysed in this study. Firstly, the FTIR spectra of fresh plane wood, waterlogged plane wood, and wood treated with melamine formaldehyde were analysed (Figure 3).
Figure 3. The FTIR spectra of fresh plane wood, waterlogged plane wood, and wood treated with melamine formaldehyde (MF). In this study, two pine wood samples which were treated with melamine formaldehyde, were analysed. Therefore, the FTIR spectra of fresh pine wood, waterlogged pine wood, and wood treated with melamine formaldehyde (MF) were analysed (Figure 4).
ro of
-p
Figure 4. The FTIR spectra of fresh pine wood, waterlogged pine wood, and wood treated with melamine formaldehyde (MF).
Jo
ur
na
lP
re
In this study, one chestnut wood, which was treated with melamine formaldehyde, was analysed. Therefore, the FTIR spectra of fresh chestnut wood, waterlogged chestnut wood, and wood treated with melamine formaldehyde (MF) were presented in Figure 5.
Figure 5. The FTIR spectra of fresh chestnut wood, waterlogged chestnut wood, and wood treated with melamine formaldehyde (MF).
When all the spectra are examined, it is seen that peaks are concentrated especially in 1800800 cm region. On the other hand, this wavelength range gives information about the changes of cellulose, hemicellulose and lignin components in the structure of the waterlogged wood [32]. In addition, a new peak at ~813 cm-1 (the peaks are shown on the spectra as A with dotted line) can be identified on spectra of treated woods in Figure 3, 4, and 5. The band at ~ 810 cm-1 was determined which is formed due to the presence of triazine [20]. It was understood that it is the distinctive band on the spectra of melamine formaldehyde treated woods in order to determine the impregnation. Absorbance spectra of the 20 samples, which were treated with the melamine formaldehyde, were presented in Figure 6. In order to determine the impregnation of the melamine formaldehyde into the woods, the spectra were examined in the range of 700-900 cm-1. A strong peak at 813 cm-1 (the peaks are shown on the spectra as A with dotted line) can be observed in all spectra.
na
lP
re
-p
ro of
-1
Figure 6. The FTIR spectra of wood samples which were treated with melamine formaldehyde.
Jo
ur
FTIR spectra of melamine formaldehyde were studied by Merline et al and Cesar et al in detail. When changes of the FTIR bands during polymerization were analysed in these studies, it was obtained that the bands, except the band at ~ 810 cm-1, were very similar to the bands of the woods. The band at ~ 810 cm-1 is related to bending vibration of triazine. Formation of this band in the spectra of the core wood samples, which were treated with melamine formaldehyde, reveals that the polymer impregnated into the wood. Moreover, it is understood that the melamine has reacted to methylol groups and there is no residual melamine and formaldehyde remains with formation of this band [20-33]. In addition, FTIR analyses were done on the samples, which were impregnated but not dried in the oven in order to determine the success of the impregnation of the resin. Three core samples were analysed with the FTIR method and spectra were examined (Figure 7). These samples were taken from oak wood. Therefore, the FTIR spectra of fresh oak wood, waterlogged oak wood, and wood treated with melamine formaldehyde (MF) were examined. A strong peak at 813 cm-1 (the peaks are shown on the spectra as A with dotted line) can be observed in all spectra. It shows that resin impregnated into wood.
ro of -p
Figure 7. The FTIR spectra of wood samples, waterlogged oak wood, and fresh oak wood.
Conclusion
lP
4.
re
The strong peak at 813 cm-1 (the peaks are shown on the spectra as A with dotted line), which is formed due to the presence of triazine, can be observed in all spectra. It shows that resin impregnated into wood and then wood samples can be dried.
Jo
ur
na
Although more than 50 years have passed since melamine formaldehyde method was developed for conservation of waterlogged wood, several numbers of studies on chemical analyses of the method were not done. Even if the method is irreversible and therefore it is problematic for the conservators, it can be used for the conservation of the highly degraded waterlogged archaeological woods. There are many steps of a successful conservation process and the success of these steps must be followed by conservators. In conservation methods with replacing the water in the wood with a consolidant, it is crucial to determine the impregnation of the consolidant into the wood. In Yenikapı Shipwrecks Project, melamine formaldehyde method is used for conservation of highly degraded wood. The removal of the cured polymer from the surface of the wood is very difficult and can damage the wood. Therefore, the impregnation process is followed very carefully. The melamine formaldehyde solution during the impregnation process should be monitored. Controlling of the pH and the turbidity of the solution provide preventing of the accumulation of the cured polymer in the surface of the wood. On the other hand, impregnation of the resin into the thick woods before the decreasing of the pH value of the solution should also be checked. In order to determine the success of the impregnation of the resin into the wood, FTIR analyses were performed on melamine formaldehyde treated dried woods. Firstly, melamine formaldehyde treated samples were divided into group by wood species. Four different species of wood were analysed in this study. To examine the spectra of the melamine formaldehyde treated wood samples, spectra of fresh wood, waterlogged wood, and treated wood were compared considering the wood species. With analysing the spectra of fresh wood, waterlogged wood, and treated wood, it was found that the formed bands were similar to each other except the band at ~ 810 cm-. This peak is not found in
the spectra of fresh wood or waterlogged wood. This band is related to bending vibration of triazine and formation of this band shows that wood is impregnated with melamine formaldehyde. After this determination, FTIR analyses were done on the wood samples which were taken from melamine formaldehyde solution box before the drying process to determine the impregnation. The bands at ~ 810 cm were observed in the spectra of these samples. It was found that these woods were impregnated with melamine formaldehyde successfully and they can be dried. On the other hand, the bands are formed during the curing of the melamine formaldehyde can not be detected easily because very similar bands were present on the spectra of wood.
Declaration of conflicting interests The Authors declares that there is no conflict of interest.
ro of
Acknowledgments
Jo
ur
na
lP
re
-p
We would like to acknowledge Prof. Dr. Ufuk Kocabaş, Istanbul Archaeology Museums, and Yenikapı Shipwrecks Project Team for their help and support. We thank Prof. Eleanor Schofield and The Mary Rose Trust for their permission to use of FTIR, and Scientific and Technological Research Council of Turkey (TUBITAK) for their support. The IU Yenikapı Shipwrecks Project has been realized with the financial support of İstanbul University Scientific Research Projects Unit (Project nos: 2294, 3907, 7381, 12765, SDK-2016-3777, SDK-2016- 3776).
References G. McConnachie, Air drying behaviour of waterlogged archaeological woods from the Tudor warship Mary Rose, Doctoral dissertation, University of Portsmouth (2005).
[2]
A. Maccotta, P. Fantazzini, C. Garavaglia, I. D. Donato, P. Perzia, M. Brai, F. Morreale, Preliminary 1H NMR study on archaeological waterlogged wood. Annali di Chimica: Journal of Analytical, Environmental and Cultural Heritage Chemistry, 95(3‐4), (2005) 117-124, https://doi.org/10.1002/adic.200590013.
[3]
M. P. Colombini, J. J. Lucejko, F. Modugno, M. Orlandi, E. L. Tolppa, L. Zoia, A multi-analytical study of degradation of lignin in archaeological waterlogged wood. Talanta, 80(1), (2009) 6170, https://doi.org/10.1016/j.talanta.2009.06.024.
[4]
C. G. Björdal, Microbial degradation of waterlogged archaeological wood. Journal of Cultural Heritage, 13(3), (2012) 118-122, https://doi.org/10.1016/j.culher.2012.02.003.
[5]
C. Capretti, N. Macchioni, B. Pizzo, G. Galotta, G. Giachi, D. Giampaola, The characterization of waterlogged archaeological wood: the three Roman ships found in Naples (Italy). Archaeometry, 50(5), (2008) 855-876, https://doi.org/10.1111/j.1475-4754.2007.00376.x.
[6]
R. J. Barbour, Treatments for waterlogged and dry archaeological wood. Archaeological wood, (1990) 177-192, https://doi.org/10.1021/ba-1990-0225.ch007.
[7]
M. Christensen, M. Frosch, P. Jensen, U. Schnell, Y. Shashoua, O. F. Nielsen, Waterlogged archaeological wood—chemical changes by conservation and degradation. Journal of Raman Spectroscopy, 37(10), (2006) 1171-1178, https://doi.org/10.1002/jrs.1589.
[8]
J. M. Coles, E. Heritage, Waterlogged wood: guidelines on the recording, sampling, conservation, and curation of structural wood (1990).
[9]
D. Gregory, P. Jensen, K. Strætkvern, Conservation and in situ preservation of wooden shipwrecks from marine environments. Journal of Cultural Heritage, 13(3), (2012) 139-148, https://doi.org/10.1016/j.culher.2012.03.005.
na
lP
re
-p
ro of
[1]
ur
[10] U. Kocabaş, Theodosius Limanı’nda Hayat, Batıklar ve Hızlı Bir Gömülme/Life at the Theodosian Harbour, Wrecks and A Rapis Silting. Yenikapı’nın Eski Gemileri/The Old Ships of the New Gate, Ed. U. Kocabaş, (2008) 23- 37.
Jo
[11] U. Kocabaş, Byzantine Shipwrecks at Yenikapı. Between Continents. Proceedings of the Twelfth Symposium on Boat and Ship Archaeology Istanbul 2009, Ed. N. Günsenin, (2012) 107114. [12] U. Kocabaş, Geçmişe Açılan Kapı Yenikapı Batıkları. Ege Yayınları, İstanbul (2015). [13] U. Kocabaş, The Yenikapı Byzantine‐Era Shipwrecks, Istanbul, Turkey: A preliminary report and inventory of the 27 wrecks studied by Istanbul University. International Journal of Nautical Archaeology. 44.1, (2015) 5-38, https://doi.org/10.1111/1095-9270.12084. [14] N. Kılıç, A. G. Kılıç, Conservation of Yenikapı Shipwrecks: From the Beginning to the Present. 14th ICOM-CC Wet Organic Archaeological Materials Working Group Conference, Portsmouth, UK, (2019) 70.
[15] J.I. Hedges, The Chemistry of Archaeological Wood. Archaeological Wood: Properties, Chemistry, and Preservation. Ed. R. J. Barbour, R. M. Rowell, American Chemical Society, Advences in Chemistry Series, 225, (1990) 111-140. [16] M. L. E. Florian, Scope and History of Archaeological Wood. Archaeological Wood: Properties, Chemistry, and Preservation. Ed. R. J. Barbour, R. M. Rowell, American Chemical Society, Advences in Chemistry Series, 225, (1990) 3-34. [17] N. Kılıç, A.G. Kılıç, Physical Properties for the Characterization of Waterlogged Archaeological Woods of Eight Yenikapı Shipwrecks from Byzantine Period. Mediterranean Archaeology and Archaeometry, Vol. 19, No 2, (2019) 133-148, https://doi.org/10.5281/zenodo.3364819. [18] M. Christensen, H. Kutzke, F. K. Hansen, New materials used for the consolidation of archaeological wood–past attempts, present struggles, and future requirements. Journal of Cultural Heritage, 13(3), (2012) 183-190, https://doi.org/10.1016/j.culher.2012.02.013.
ro of
[19] S. Collis, Revisiting Conservation Treatment Methodologies for Waterlogged Archaeological Wood: An Australian Study. AICCM Bulletin, 36(2), (2015) 88-96, https://doi.org/10.1080/10344233.2015.1111597.
-p
[20] D. J. Merline, S. Vukusic, A. A. Abdala, Melamine formaldehyde: curing studies and reaction mechanism. Polymer Journal, 45(4), (2013) 413, https://doi.org/10.1038/pj.2012.162.
re
[21] M. Wittköpper, Current development in the preservation of archaeological wet wood with melamine/amino resins at the Römisch – Germanisches Zentralmuseum. Archäologisches Korrespondenzblatt, 28, (1998) 637-64.
lP
[22] P. Hoffmann, M. Wittköpper, The Kauramin Method for Stabilizing Waterlogged Wood. Proceedings of the 7th ICOM-CC Working Group on Wet Organic Archaeological Materials Conference, Ed. C. Bonnot-Dicconne, X. Hiron, P. Hoffmann, (1999) 163-166. [23] N. Kılıç, A. G. Kılıç, Kauramin® Tests for Yenikapı Shipwrecks. 12th ICOM-CC Working Group on Wet Organic Archaeological Materials, Istanbul, (2013) 222-227.
na
[24] N. Kılıç, Conservation of a Group of Frames from YK 16 Shipwreck. Art-Sanat, (6), (2016) 85-97.
ur
[25] S. G. Kazarian, K. L. A. Chan, FTIR Imaging of Polymeric Materials. Polymer Morphology: Principles, Characterization, and Processing, (2016) 118-130, https://doi.org/10.1002/9781118892756.ch7.
Jo
[26] S. Akyüz, Investigation of the degradation stages of archaeological and historic silk textiles: An ATR-FTIR spectroscopic study. Archaeology Anthropology: Open Access, 3-1, (2018) 447-451, https://doi.org/10.31031/AAOA.2019.03.000573. [27] B. Pizzo, A. Alves, N. Macchioni, A. Alves, G. Giachi, M. Schwanninger, J. Rodrigues, Characterization of waterlogged wood by infrared spectroscopy. Proceedings of Wood Science for Conservation of Cultural Heritage, (2008) 5-7. [28] M. Broda, B. Mazela, K. Królikowska-Pataraja, C. A. Hill, The use of FT-IR and computed tomography non-destructive technique for waterlogged wood characterisation. Wood Res Slovakia, 5, (2015) 707-722.
[29] M. Traoré, J. Kaal, A. M. Cortizas, Application of FTIR spectroscopy to the characterization of archeological wood. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 153, (2016) 63-70, https://doi.org/10.1016/j.saa.2015.07.108. [30] E. McHale, C. C. Steindal, H. Kutzke, T. Benneche, S. E. Harding, In situ polymerisation of isoeugenol as a green consolidation method for waterlogged archaeological wood. Scientific Reports, 7, (2017) 46481, https://doi.org/10.1038/srep46481. [31] Ü. Akkemik, Woods of Yenikapi Shipwrecks. Ege Yayınları, Istanbul (2015). [32] C. Pozo, J. Díaz-Visurraga, D. Contreras, J. Freer, J. Rodríguez, Characterization of temporal biodegradation of radiata pine by Gloeophyllum trabeum through principal component analysis-based two-dimensional correlation FTIR spectroscopy. Journal of the Chilean Chemical Society, 61(2), (2016) 2878-2883. https://doi.org/10.4067/s071797072016000200006
Jo
ur
na
lP
re
-p
ro of
[33] T. Cesar, T. Danevčič, K. Kavkler, D. Stopar, Melamine polymerization in organic solutions and waterlogged archaeological wood studied by FTIR spectroscopy. Journal of Cultural Heritage, 23, (2017) 106-110, https://doi.org/10.1016/j.culher.2016.09.009.