不同共聚体系对丙烯腈与丙烯酸单体竞聚率的影响

采用Kelen-Tudos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DMSO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/DMSO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。

EFFECT OF COPOLYMERIZATION SYSTEMS ON MONOMER APPARENT REACTIVITY RATIOS OF ACRYLONITRILE/ACRYLIC ACID

Effects of copolymerization systems on monomer apparent reactivity ratios for copolymers of acrylonitrile with acrylic acid were studied for contrast.Values of monomer apparent reactivity ratios were calculated by Kelen-Tudos method.It is found that the apparent reactivity ratios in aqueous suspension polymerization system are similar to those in solution polymerization system at polymerization conversion less than 20%.As conversion of beyond 50%,the changes of monomer apparent reactivity ratios become less prominent.In water-rich reaction medium(H_2O/DMSO>80/20),monomer apparent reactivity ratios are approximately equivalent to those in aqueous suspension polymerization system.In DMSO-rich reaction medium(DMSO/H_2O>80/20),apparent reactivity ratios are similar to those in solution polymerization system.With an increase of polarity of solvent,values of apparent reaction ratios both decrease.