Synthesis and Formation Mechanism of Large-Size Monodisperse P(Glycidyl methacrylate-Styrene) Microspheres by Batch Dispersion Copolymerization

Highly monodisperse P(Glycidyl methacrylate-Styrene) (P(GMA-St)) microspheres with spherical shape and smooth surface were prepared via batch dispersion copolymerization of GMA and St in ethanol medium, using 2,2′-azobisisobutyronitrile (AIBN) as initiator and polyvinylpyrrolidone (PVP) as stabilizer, respectively. The effects of various polymerization parameters such as St/GMA ratio and total monomer concentration on the morphology, particle size and size distribution were investigated. It was found that P(GMA-St) microspheres could be obtained with a size range of 2 to 9 μm by changing the solubility parameter of reaction mixture. St/GMA ratio had an important effect on the particle size and size distribution, and increasing the relative percentage of styrene in the mixture lead to an increase in particle size and a decrease in the molecular weight of copolymer when the St/GMA ratio was not more than 1. Monodisperse microspheres were obtained when the total monomers loading ranged from 10 to 25 wt%. Inner structure was observed by optical microscopy and a reasonable formation mechanism of P(GMA-St) was proposed.