Research On The ?-caprolactone In Waterlogged Wood And Archaeological Waterlogged Wood Samples Dehydration And Consolidation

Dehydration and consolidation is a critical step for archaeological waterlogged wood conservation,?-caprolactone is a non-toxic polyester monomer,the ring-opening polymerization(ROP)will be induced under the catalytic condition,and forming the PCL molecule that is a hydrophobic elastic polyester chain.In this study,CL as the mainly material for waterlogged wood dehydration and consolidation,the CL monomer and the CL compound dehydration material were studied which apply on the Scots pine waterlogged wood and the seriously degraded archaeological waterlogged wood samples from Wanjiao I shipwreck relic,the efficiency and mechanism of dehydration and consolidation were reported.The bulking efficiency of PCL in the wood cell walls was discussed.The dehydration and consolidation process in this study mainly included two steps:impregnation at the room temperature and the polymerization under the 500C.The mainly study and results are listed:The PEG400 water solution,the PEG400/?-caprolactone compound solution and the CL monomers were applied for Scots pine waterlogged wood specimens dehydration,the oxalic acid as catalyst was pre-impregnated before the dehydration process.The results showed that the dry weight gain percentage of the treated wood specimens with CL were increased obviously,the ROP reaction of CL was induced successfully and forming the PCL insert into the wood structures.The waterlogged wood remain dimensional stability and the wood cell walls become hydrophobic bulking with the PCL.The PEG400,CL,glyoxal(GXL)and DMDHEU(2D)resin as the dehydration material for the Scots pine waterlogged wood,and MgC12·6H2O as the catalyst.Three gradient concentrations(25%,50%and 75%)of four dehydrating material were studied.The study results showed that the dimensional stability of wood specimens treated with four dehydration agents better at the 50%and 75%concentrations,the ROP reaction of CL was able to be catalyst by the MgCl2·6H2O,and the PCL inserted into the wood structures.Water-soluble GXL polymers filled in the wood structures.The wood specimens treated with 2D resin have high moisture absorption and water-uptake efficiency,but the lower water loss rate values.The compound dehydration agents were prepared by CL with GXL,CL with 2D,PEG400 with GXL and PEG400 with 2D,and the compound dehydration agent was divided into two groups which is CL compound groups and PEG400 compound groups.Compared with the two groups treatment efficiency,the results showed that the CL compound treatments were similar to the PEG400.The GXL polymers and PCL were bulking in the wood structures together,and the 2D resin have the corss-linking function with PCL.The CL,CL/GXL and CL/2D compound dehydration material were applied on the seriously degraded archaeological waterlogged wood samples.The results showed that the dehydration and consolidation treatment with these agents was successful,the higher water content the more obviously dry weight gain percentage increased,the PCL and compound material polymers were filled into the wood structures to support the fragile wood components and prevent the collapse of wood cell walls.