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采用K e len-T udos方法,测定了丙烯腈(AN)与丙烯酸(AA)共聚合反应体系中单体竞聚率,探讨了不同反应体系对单体竞聚率的影响。结果表明,在水相悬浮聚合体系中,当转化率小于20%时,两单体的竞聚率同DM SO均相溶液聚合结果相近;随转化率的增加,AN竞聚率增加,AA竞聚率减小,当转化率超过50%后,两单体竞聚率变化不明显。在H2O/DM SO混合溶剂沉淀聚合中,当水含量超过80%后,两单体竞聚率向水相悬浮聚合结果靠近。随溶剂极性增大,rAN与rAA值均减小。
The monomer reactivity ratio in the copolymerization of acrylonitrile (AN) and acrylic acid (AA) was measured by K e len-T udos method. The influence of different reaction systems on the monomer reactivity ratio was also discussed. The results showed that when the conversion was less than 20%, the reactivity ratio of the two monomers was similar to that of the homogeneous solution of DM SO in the aqueous suspension polymerization system. With the increase of the conversion, the reactivity ratio of AN increased, When the conversion rate exceeds 50%, the reactivity ratio of two monomers is not obvious. In the H2O / DM SO mixed solvent precipitation polymerization, when the water content exceeds 80%, the reactivity ratio of the two monomers is close to that of the aqueous suspension polymerization. With the increase of solvent polarity, rAN and rAA values decreased.