甲基丙烯酸甲酯-苯乙烯共聚物分子质量的研究

Molecular Weight of Methyl-Methacrylate-Styrene Copolymers

在６０～９０℃温度范围内，以ＡＩＢＮ为引发剂进行了甲基丙烯酸甲酯（ＭＭＡ）－苯乙烯（Ｓｔ）本体自由基共聚合，用粘度法测定了共聚物的分子质量。在转化率０～９５％范围内，研究了聚合温度、引发剂浓度及单体配比对ＭＭＡ－Ｓｔ共聚物分子质量的影响规律，结果表明自由基聚合过程中凝胶效应使共聚物分子质量随转化率升高而显著增大；推导并关联了共聚物平均分子质量模型，在凝胶效应出现之前，该模型计算值与实验值平均偏差８％，为ＭＭＡ－Ｓｔ共聚物的生产控制提供了理论依据。

The bulk copolymerization of MMA-St was initiated by AIBN at 60～90℃. The viscometric average molecular weight of copolymers was measwred. The influences of monomer composition,concentration of initiator and polymerization temprature on molecular weight were analysed among the conversion range 0 to 95%. The results showed that during copolymerization the gel effect makes molecular weight increasing obviously with the conversion rate increasing. A model of average molecular weight of copolymer was derived from related data. Before the gel effect apptars, the average error between calculated value by the model and measured value practically is 8%. The result provides a theoritical base for MMA-St copolymer produetion control.