醋酸乙烯酯与丙烯酸甲酯的种子乳液聚合

SEEDED EMULSION POLYMERIZATION OF VINYL ACETATE ONTO POLYMETHYL ACRYLATE INITIATED BY 2,2′-AZOBISISOBUTYRONITRILE

以过硫酸铵（ＡＰＳ）为引发剂，对丙烯酸甲酯（ＭＡ）的乳液聚合进行了研究，得出在ＭＡ／Ｈ２Ｏ重量比为０．５时，６０℃下合成粒径分布均匀的聚丙烯酸甲酯（ＰＭＡ）种子乳液的最佳配方为：十二烷基硫酸钠（ＳＤＳ）、（ＡＰＳ）和（ＮａＨＣＯ３）的浓度分别为１１．６、１．７２和４．６９ｍｍｏｌ／Ｌ．然后以ＰＭＡ乳液为种子，以油溶性偶氮二异丁腈（ＡＩＢＡ）为引发剂，分别进行不溶胀与溶胀条件下醋酸乙烯酯（ＶＡ）的种子乳液聚合，并以磷钨酸为染色剂。

Polymethyl acrylate(PMA) latex particle with narrow diameter distribution was first prepared by batch process with ammonium persulfate as initiator,then the two-stage emulsion polymerization of vinyl acetate(VA) onto PMA were carried out by using oilsoluble initiator 2,2'-azobisisobutyronitrile(AIBN) under unswelling and swelling conditions at 60 ℃ for 8 h.The ratio of polymer to water is 1/2 completed conversion,and the ratios of monomer to seed polymer are varied for all polymerizations.Particle size and morphologies were characterized by TEM with phosphotungstic acid(PTA) as dying agent.Results showed that experimental particle size and Np value are consistent with the theoretical Value for all of seeded emulsion polymerizations,and interpenetrating network particle morphologies were observed under unswelling or swelling conditions at different ratios of PMA to VA.In a conclusion,initiation and polymerization of VA mainly occurred in PMA seed particle swelled with VA, and homonucleation of VA in water is less important.