反应性分散稳定剂对聚合物颗粒形态与粒径的影响

Effects of Reaction Stabilizer on Morphology and Diameter of Polymer Particles

在一定比例的醇/水混合介质中,以甲基丙烯酸酯单封端的聚乙二醇(PEG)大分子单体为反应性分散稳定剂,使其与丙烯腈/苯乙烯(丙烯腈为主单体)进行了三元自由基分散共聚反应,制得了粒径均一、分散稳定、尺寸为亚微米级并具有特殊形态的聚合物颗粒.采用透射电子显微镜和激光光散射等手段对聚合物颗粒进行了表征,发现大分子单体浓度及相对分子质量对其形态与颗粒大小有明显的影响.进而根据实验结果建立了PEG大分子单体与苯乙烯/丙烯腈单体的质量比和颗粒大小间的定量关系,用于预测控制颗粒直径的聚合反应条件.

Poly（ethylene glycol） （PEG） macromonomer with a vinyl end group was selected as reacting stabilizer. The PEG grafted polyacrylonitrile/polystyrene （PEG-PAN/PSt） particles were prepared by free radical copolymerization of acrylonitrile with styrene in the presence of PEG macromonomer in ethanol/water mixed solvents at 60℃ for 24 h. The effects of concentration and molecular weight of PEG macromonomer on the particle size and morphologies were studied. It was found that the resulting PEG-PAN/PSt particles have unusual form, distribution uniform in diameter and dispersion stability in water. Changing concentration and molecular weight of PEG macromonomer could control the particle size and their morphology. A quantitative relation between the particle size and the feed ratio （mass ratio of macromonomer to total monomers） was obtained as Wm/Wp = 6. 20 × 10^-2R h- 3. 49. The mathematics model can be used to control particle size for reaction conditions.