木質材料の改良に関する研究(第14報) : 木材内メタクリル酸メチルの光重合におよぼす金属イオンの影響

On photo-induced polymerization of methyl methacrylate (MMA) into HINOKI (Chamaecyparis obtusa), the sensitizing effect of adsorbed metallic ions on wood flour was investigated. The wood flour (40-60 mesh) was immersed in 10-50 mmol/l aqueous solution of each metallic salt at 45℃ for 60 min. (liqour ratio 80) and then was washed with water. The amount of metallic ion adsorbed by the wood flour was derived from the weights of ash. Polymerization was conducted by irradiating with light (high pressure mercury lamp) in a hard glass vessel consisting of 0.50 g of wood flour on which metallic ions were adsorbed, 2.5 ml of MMA and 20 ml of water.
The results of this experiment are as follows :
1) The amount of adsorbed metallic ion on wood flour decreased in the order <Fe>^<3+> ＞ <Cu>^<2+> ～__＝ <Ag>^+ ＞ <Fe>^<2+>. These maximun amounts were in the range of 1.5-3 mmol/100gof wood flour for each metallic ion, except for adsorbed <Fe>^<3+> which amounted to about 5 mmol/100 g of wood flour.
2) The photo-induced polymerization of MMA was accelerated by a slight amount of adsorbed <Fe>^<3+> or <Fe>^<2+> comparing with the unadsorbed wood flour, and was not affected by <Cu>^<2+> and <Ag>^+.
3) It was also observed that <Fe>^<3+> and <Fe>^<2+> had remarkable sensitizing effect on photo-induced graft copolymerization of wood components and MMA.
4) Clear relation was not observed between the amount of adsorbed metallic ion and polymer formation.