聚苯乙烯大单体与乙酸乙烯酯的共聚及其接枝共聚物的表征

研究了聚苯乙烯大单体与乙酸乙烯酯的溶液聚合,结果表明,接枝效率随引发剂用量、聚合温度及小单体与大单体的投料比的增加而增加,随大单体的分子量增加而减少,而随单体浓度的变化呈现一最大值。共聚过程中大单体的转化率开始较小单体的增加快,后期变慢。用萃取法纯化的接枝共聚物经GPC、IR、~1H-NMR及PGC等表征,并算得平均接枝数为4—7。透射电镜表明接枝共聚物中存在微观相分离。

COPOLYMERIZATION OF POLYSTYRENE MACROMERS WITH VINYL ACETATE AND CHARACTERIZATION OF THE GRAFT COPOLYMERS

The copolymerization of polystyrene macromers with vinyl acetate was studied. The results show that the grafting efficiency increases with amount of initiator, polymerization temperature and charging ratio of vinyl acetate to the macromer, and decreases with increasing average molecular weight of the macromers. There exists a maximum value in the relationship between the grafting efficiency and the total monomers concentration. During copolymerization the conversion rate of the polystyrene macromer is faster than that of vinyl acetate at the beginning while slower at the later stage. The graft copolymers were purified by extractions and characterized by GPC, IR, 1H-NMR,PGC and TEM. The last indicates a microphase separation in the graft copolymer.