木質材料の改良に関する研究(第9報) : カラマツ中におけるメタクリル酸メチルの重合

In order to elucidate the effects of pre-extraction with alcohol-benzene(1:2), Polymerization atmosphere, concentration of an initiator and addition of methyl alcohol(MeOH) on radical polymerization of vinyl monomer into Karamatsu(Larix leptolepis Gordon) for the purpose of Karamatsu-WPC(wood-plastic combination), the effects of these factors on the rate of polymerization and induction period which were evaluated from the conversion curves of methyl methacrylate(MMA) into Karamatsu were investigated.
The preparation of WPC was carried out by the polymerization of Karamatsu-MMA system into glass ampoules at 60℃. The rate of polymerization was calculated from the percentage of conversion per minute on the state of high yield of polymerization, and the induction period was estimated from the retardation and transition time.
The results obtained are as follows :
1) Pre-extraction has little effect on the rate of polymerization, but the induction period on the pre-extracted species is reduced by one half. It is found that alcohol-benzene extractives show some retardation effects.
2) It is recognized that there are remarkable effects of the atmosphere of air or nitrogen on the rate of polymenzation and induction period for polymerization of MMA into Karamatsu.
3) The rate of polymerization of MMA into Karamatsu increases and induction period decreases along with the increased concentration of an initiator.
4) The amount of MeOH in the MMA-MeOH system affects remarkably the polymerization of MMA into Karamatsu. In the case of 30% concentration of MeOH, the retardation effect is still maintained after polymerization for 24 hrs.