快速膜乳化法制备尺寸均一及结构可控聚苯乙烯微粒

Preparation of Uniform and Heterogeneous Structure Polystyrene Particles by Premix Membrane Emulsification

以苯乙烯为单体、二乙烯基苯为交联剂,采用快速膜乳化法制备了聚苯乙烯微粒,对其粒径分布、制备重复性、颗粒结构进行了表征,并考察了致孔剂种类及用量对不同粒径颗粒形态结构的影响规律.结果表明,聚苯乙烯颗粒粒径与所用膜孔径呈线性关系,最佳乳化压力与膜孔径呈反函数关系.优化工艺条件下所制颗粒粒径为1～6m,粒径分布系数均小于0.8,批次相对标准偏差低于3%.体积效应对小粒径颗粒的成型结构影响较大;粒径越小,颗粒成型时致孔剂与聚合物间的相分离程度越低,颗粒粒径小于2m时液体石蜡无法形成完整颗粒,颗粒粒径大于2m时十六烷用量在60%(ω)以下才能形成大孔结构.

Uniform polystyrene （PST） particles with controlled heterogeneous structure were synthesized by premix membrane emulsification method, the effects of the emulsification pressure and cycles, pore size of the membrane used, and porogen on the PST particle size and uniformity were studied. The results indicate that the membrane pore size has linear relation with the average diameter of PST particles and is in inverse proportion to the optimum emulsification pressure. The prepared PST particle sizes can be controlled in 1-6 μm with the size distribution index Span of 0.8, and the relative standard deviation of reproducibility within 3%. Furthermore, the degree of phase separation between polymers and porogen decreases with decreasing of the particle size. Liquid paraffin is unsuitable as the porous medium for the particle size smaller than 2 μm, hexadecane can be used as macroporous medium but with the dosage of under 60% when the particle size is larger than 2 μm.