Growth Mechanism Of Mono-Disperse Microspheres Of Poly(Styrene-Co-Maleic Anhydride) In Self-Stabie Precipitation Polymerization

Self-stable precipitation polymerization, as one of methods of preparation of mono-disperse polymer microspheres, has been discovered recently. Comparing with the existing methods of preparation of mono-disperse polymer microspheres, such as emulsion polymerization, dispersion polymerization, seeded polymerization and precipitation polymerization, the advantages of self-stable precipitation polymerization include no need to add any stabililizer or surfactant, neatness in microsphere surface, convenience to deal with production after experiment, no need to agitate, high concentration of monomer reaching as much as 40% of the weight of reactant and short polymerization time. This paper mainly researched on the growth mechanism of mono-disperse microspheres of poly(styrene-co-maleic anhydride) in self-stable precipitation polymerization.Mono-disperse microspheres of poly(styrene-co-maleic anhydride) were prepared by self-stable precipitation polymerization in 80℃, with AIBN as initiator and ethyl butyrate as solvent. The growth mechanism of mono-disperse microspheres of poly(styrene-co-maleic anhydride) initiated by AIBN in self-stable precipitation polymerization was proposed by researching on the conversion of monomer, the molecular of poly(styrene-co-maleic anhydride), the morphology and size of microspheres in different polymerization time.The macroinitiator containing ITXH moiety was synthesized by photo reaction with 4-isopropylthioxanthone (ITX) as photoinitiator and ethyl 4-dimethylaminobenzoate (EDAB) as coinitiator. The optimum conditions were attainted by series of parallel experiments. Mono-disperse microspheres of poly(styrene-co-maleic anhydride) was prepared by self-stable precipitation polymerization with marcoinitiator as initiator. The reinitiation of macroinitiator is living. The growth mechanism of mono-disperse microspheres of poly(styrene-co-maleic anhydride) initiated by macroinitiator by self-stable precipitation polymerization was proposed.Mono-disperse microspheres of poly(styrene-co-maleic anhydride) was prepared by self-stable precipitation polymerization by RAFT. The polymerization of adding RAFT after and before particle formation, seeded polymerization of microspheresⅠandⅡwere investigated. The growth mechanism of mono-disperse microspheres of poly(styrene-co-maleic anhydride) in self-stable precipitation polymerization by RAFT, which is similar with the system of initiation of macroinitiator, was proposed.