Lnhibiting Effect of Extractives of Larix leptolepis on Radical Polymerization

Abstract

To elucidate the inhibiting effect of extractives of Karamatsu (Larix lePtolepis) on the radical polymerizasion of vinyl monomer within Karamatsu, the polymerization of vinyl acetate in the presence of extractives of Karamatsix was investigated by thd use of a dilatometer.As a result, in the polymerization of vinyl acetate brought about by the addition of cold water hot water, alkali, ether, acohol benzene (1 : 2) and acetone extractives, the clear induetion peried was observed at 47C and 40eC, but in the case ef alcohol-benzene(1:2) and acetone extractives at 40eC.Upon additionof cold and hot water extractives, a proponal relatin was observed between the induction period and' amount of extractives added. Also, as to the retardating effect, the retardating efficiency was evaluated from a ratio of k to kek where k is the rate constant of the reaction involving various extractive and ko is that not involving them and the order of the inhibiting effect on radical polymerization was as follows alkali extractivesther extractives lcohol-benzene (1 : 2) extraetivesaeetone extractives.