Preparation Of Monodisperse Copolymers Microspheres By Self-stable Precipitation Polymerization

Monodisperse flower-like poly(maleic anhydride -co-vinyl acetate) microspheres were prepared by the method of self-stable precipitation polymerization. Influences of composition of mixed solvents, category of initiators, monomer concentration and reaction temperature on morphology and size of copolymers were investigated. The formation process of flower-like copolymer microspheres was studied, and it's demonstrated that the evolution of polymerization was in accordance with the evolution of polymeric microspheres' growth.Mechanism of formation and growth of monodisperse flower-like microspheres was also investigated. Effects of solubility parameter of reaction medium on morphology and size of poly(maleic anhydride-co-vinyl acetate) was studied, and monodisperse spherical and smooth microspheres were prepared which were used as template in preparing polymer macroporous materials.Microspheres and string-like particles of cross-linked poly(maleic anhydride-co-vinyl acetate) were prepared, and the effects of reaction on their morphology and size were investigated. The radical copolymerization of maleic anhydride and styrene was operated in different solvents, and the result of experiments indicated that a proper window is essential to the self-stable precipitation polymerization and the formation of monodisperes microspheres, and the result also demonstrated the the morphology of copolymers evolved with the increase of solubility parameter of reaction medium. The chemical construction of poly(maleic anhydride-co-styrene) was characterized; Influences of monomer concentration, monomer molar ration, co-solvent and reaction temperature on morphology and size of copolymers were also investigated; The formation process of microspheres was studied,and it's demonstrated that the curve of polymerization conversion versus time owned the feature of precipiation polymerization and the evolution of polymerization was in accordance with the evolution of polymeric microspheres' growth.Mechanism of growth of copolymers was also studied.Cross-linked poly(maleic anhydride-co-styrene) microspheres were prepared and effects of category and amounts of crosslinkers on morphology and size of copolymer microspheres were investigated.