离子单体和纳米二氧化硅对聚苯乙烯微球制备的影响

Effects of Ionic Monomer and Colloidal Silica on Preparation of Polystyrene Microsphere

以对苯乙烯磺酸钠(SSS)与苯乙烯组成无皂乳液聚合体系(PS-SSS)制备了粒度不等的窄分布聚苯乙烯(PS)微球,微球粒径可在60～700nm之间调节,粒径分布控制在2%之内。在PS-SSS体系中SSS用量增多会使PS微球的尺度下降,但对粒径分散性没有影响。PS的数均分子量会随着SSS用量增多而略有下降。随着引发剂用量的增多,PS微球粒径会下降,PS的数均分子量明显下降。在二氧化硅溶胶中可稳定制备聚苯乙烯微球,在PS-SSS体系中引入纳米二氧化硅溶胶(NanoSiO2)组成NanoSiO2-PS-SSS体系,可对微球粒度进行调制,NanoSiO2用量的增多会导致制备的聚苯乙烯微球粒径下降,对于微球PS的数均分子量影响很小。聚苯乙烯中引入SSS后会增加苯乙烯聚合速率,提高制备的聚苯乙烯的玻璃化转变温度。

Polystyrene （PS） microspheres with various sizes and narrow size distribution were prepared using sodium styrenesulfonate （SSS） and styrene as a soap-free emulsion system （PS-SSS）. Their sizes were tunable from 60 nm to 700 nm, and the size distribution could be well controlled within 2%. In the PS-SSS system, the diameter of PS spheres decreases with increasing the amount of SSS while it has no impact on the particles size distribution. The number-average molecular weight of PS slightly decreases with the increase of the amount of SSS in the composition. The particle size and the molecular weight of PS microspheres decrease with increasing the amount of initiator. The PS microspheres can be prepared in the nanosize silica sol （NanoSiO2）. The size of PS microspheres can be modulated by introducing NanoSiO2 into the PS-SSS system to form a hybrid system： NanoSiO2-PS-SSS. Increasing the content of NanoSiO2 can reduce the particle size while has no impact on the molecular weight of PS. The polymerization rate of styrene is accelerated with the introduction of SSS in the system, and the glass transition temperature of the PS is enhanced.