St/BA/DBMPA无皂阳离子共聚物乳胶粒研究

选用苯乙烯（St)、丙烯酸丁酯（BA）和少量的反应性阳离子共聚单体N，N－二甲基，N－丁基，N－（3－甲基丙烯酰胺基）丙基溴化铵（DBMPA），以阳离子自由基型引发剂引发进行无皂乳液聚合，合成了稳定的无皂阳离子共聚物St/BA/DBMPA乳液。研究结果表明：增大阳离子单体浓度、引发剂浓度和主单体St/BA体积比，共聚物乳胶粒粒径减小，粒子数目增大；增大离子强度，粒径呈现一个增大－减小－增大的变化过程；粒子的表面电荷密度也由以上4个因素决定。所合成的乳液表面张力小，耐电解质和耐有机溶剂性能好，说明该乳液具有很高的化学稳定性。胶膜经高温处理后，耐水性大大提高。

Study on the soap-free cationic copolymer latex particles of St/BA/DBMPA

Soap-free emulsion copolymerization of styrene (St) and butyl acrylate (BA) in the presence of active cationic comonomer N, N-dimethyl,N-butyl,N-(3-methacrylamidino) propyl ammonium bromide (DBMPA) was carried out using AIBA as initiator. The result showed: the average diameter of copolymer particles (Dw), decreased and number (N p) of copolymer particle increased with increasing DBMPA and AIBA concentrations, BA content in the St/BA monomer feeding. But Dw showed a change process of increase-decrease-increase with increasing ionic strength. Moreover, the surface charge density of the particles were decided by the DBMPA content, AIBA content, St/BA mass monomer ratio and ionic strength. The surface tensions of copolymer emulsion were little, the properties of electrolyte-resistant and CH 3OH- resistant of emulsion were good and there were high chemical stabilities of copolymer emulsion. The water-resistant property of film were to be improved after high temperature and DBMPA crosslinking.