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在自由基共聚反应中,随反应进行,共聚物组成一般会发生变化,尤其是当共聚单体竞聚率差异较大时,如自由基乳液共聚合中,批量法(Batch)合成的醋酸乙烯酯(VA)与丙烯酸丁酯(BA)的共聚合乳液胶粒常具有“类核壳结构”,即胶粒内核与外壳高分子组成差异很大,为了合成具有均匀结构与组成的共聚物,本文采用了矫正批量法(Corrected batch)乳液共聚合,对VA-BA共聚体系进行了研究。结果表明选择恰当的投料速率,即使对于VA-BA这样况聚率相差很大的共聚单体对采用本过程也能够合成组成较为均一的共聚物,粒径小于批量法合成的胶粒,胶粒分散度较批量法中大,但优于半连续过程,矫正批量法中胶粒平均自由基数目在反应过程中基本保持恒定,与批量法中对本体系的研究结果形成鲜明对比,由于VA的水溶性,水相聚合在该反应过程中占有一定比重。
In the free radical copolymerization reaction, the composition of the copolymer generally changes with the reaction, especially when the reactivity ratio of the comonomer is quite different, such as the free radical emulsion copolymerization, the batch synthesis of vinyl acetate Copolymerization of esters of acrylic acid (VA) and butyl acrylate (BA) latex particles often have “core-shell structure”, that is, there are great differences between the polymer core and the shell polymer. In order to synthesize copolymer with uniform structure and composition, In this paper, Corrected batch emulsion copolymerization was used to study VA-BA copolymer system. The results show that the choice of the appropriate feed rate, even for such VA-BA such a large difference in the rate of copolymerization monomer using this process can also be more uniform composition of the copolymer synthesis, the particle size smaller than the batch synthesis of the rubber particles The dispersion degree is larger than that of the batch method, but superior to the semi-continuous process. The average number of free radicals in the colloidal particles in the calibration batch process remained basically constant during the reaction. In sharp contrast with the batch system method, Sexual, aqueous polymerization in the reaction of possession of a certain proportion.