交联剂对乳胶粒成孔的影响

EFFECT OF CROSSLINKING AGENTS ON THE FORMATION OF MULTIHOLLOW POLYMER LATEX PARTICLES

通过连续法无皂种子乳液聚合技术和碱酸分步处理法 ,合成了一系列不同含酸量、骨架为 PSt的多孔结构乳胶粒 ,考察了交联剂种类及用量对聚合反应、乳胶粒交联程度及乳胶粒成孔的影响。表明二乙烯基苯 (DVB)是该聚合反应体系合适的交联剂 ,发现乳胶粒的交联程度及不饱和酸的种类与用量是影响其成孔的关键因素。

Multihollow polymer latex particles have been of incresing interests due to their promising applications in many fields. In this paper, copolymer latex particles consisting of St MMA AA(or MAA) with different crosslinkages were first prepared through seeded emulsion polymerization in the absence of emulsifiers in the second step. Results show that divinyl benzene(DVB) is better than ethylene glycol dimethylacrylate(EGDMA) when they are used as crosslinking agents. The latexes were then treated by alkali and acid subsequently at 90 ℃ for 3 h, and particle size and morphologies were characterized by TEM using phosphotungstic acid as staining agent. It is found that the formation of multihollow structure and the change of particle volume after treatment are significantly effected by crosslinkage of particles. For samples containing AA, multihollow structure are observed in spite of crosslinkage, particle crosslinking causes an obvious decrease in particle expansion; while for samples containing MAA, only uncrosslinked particles formes multihollow structure.