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

Abstract

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.

Keywords:

• Batch dispersion copolymerization
• formation mechanism
• large-size monodisperse microsphere
• P(GMA-St) microspheres
• St/GMA ratio

Acknowledgments

Financial support from the National Natural Science Foundation of China (No. 50773063), National Basic Research Program of China (2010CB635111) and Basic Research Foundation of Northwestern Polytechnical University (G9KY1020) are highly appreciated.

Notes

^a 20% (w/w) monomer relative to total mixture; 1% (w/w) AIBN relative to monomers; 2% (w/w) PVP relative to monomers.

^b Initial solubility parameter.

^c The different between the final solubility parameter and the initial solubility parameter.

^a St/GMA (w/w) = 10/10; 1% (w/w) AIBN relative to monomers; 2% (w/w) PVP relative to monomers.

^b Monomer concentration relative to total mixture (w/w).

^c Initial solubility parameter.

^d The different between the final solubility parameter and the initial solubility parameter.