Abstract:
Polystyrene (PS) microspheres with various sizes and narrow size distribution were prepared using sodium styrenesulfonate (SSS) and styrene as a soapfree emulsion system (PSSSS). Their sizes were tunable from 60 nm to 700 nm, and the size distribution could be well controlled within 2%. In the PSSSS system, the diameter of PS spheres decreases with increasing the amount of SSS while it has no impact on the particles' size distribution. The numberaverage 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 PSSSS system to form a hybrid system: NanoSiO2PSSSS. 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.