Radiation methods of impregnating wooden cultural objects

The process was studied of polymerization in wood at low dose rates of gamma radiation. It was demonstrated that at radiation doses below the optimal level of 1.0 kGy.h-1, polymerization in wood decreased significantly. It was found that the molecular weight of polymethyl methacrylate prepared by radiation polymerization in samples of linden tree wood increased with decreasing dose rate and decreased with growing dose. It was also shown that the final size of samples after polymerization was the bigger the higher was the content of polymers in the wood attained. A study of radiation copolymerization of methyl methacrylate with butyl methacrylate in wood showed that the addition of butyl methacrylate in the monomer mixture increased the polymer yield in the wood and reduced moisture expansion of the wood during polymerization. In order to test the possible applications of obtained results a number of experiments were made which showed that the use of radiation polymerization is promising in wood which is not polychromatic. The wood surface following impregnation remained unchanged and restoration could be continued. In case of polychrom wood sculptures the application of the method was promising for tempera and gilding using a dose of less than 40 kGy at a dose rate of 1 kGy/h. In case of polychromatic wood sculptures with addition of oil binders there was the danger of damaging the object. (J.B.). 4 figs., 2 tabs., 2 refs