Synthesis Of Homopolymer, Copolymer And Core/Shell Composite Microspheres Of NVP By Dispersion Polymerization

Polyvinylpyrrolidone （PVP）, P （NVP-AM） and SiO₂/PVP core/shell microsphereswere synthesized by dispersion polymerization in mixed solvent with N-vinylpyrrolidone （NVP）, acrylamide （AM） and SiO₂as monomers, AIBN as initiator.The structures and performance of the materials mentioned above were studied.The main results are as follows:1. PVP microsphere was prepared in mixed cyclohexane/butyl acetate. Thethermal decomposition temperature of the product was429℃.The Mηof themicrosphere with good dispersibility was22.05×104g/mol. The average size of PVPmicrosphere was1.5μm and increased with the increasing NVP and AIBNconcentration and the decreasing SEBS concentration The obtained PVPmicrosphere had the best comprehensive performance within the optimum conditionof25%（w） NVP,0.6%（w） AIBN,10%（w） SEBS and the the volume ratio ofcyclohexane/butyl acetate was1:1.2. P（NVP-AM） microsphere was synthesized in mixed ethyl acetate/ethanol.The thermal decomposition temperature was418℃. The product had the bestthemostability when the mass ratio of NVP/AM was1:4. Additionally, the productpossessed good temperature-resistant and salt-tolerance. When monomers, initiator,dispersant was15-20%（w）,1.0%（w）, and15%（w） respectively, the mass ratio ofNVP/AM was1:4and the volume ratio of ethyl acetate/ethanol was8:2, theP（NVP-AM） microsphere had the best comprehensive performance.3. The SiO₂/PVP core-shell microspheres was prepared successfully incyclohexane. The results showed that the decomposition temperature of SiO₂/PVPwas422℃. the average size of the modified SiO₂microsphere increased78nmcompared with SiO₂microsphere. Also, they both possessed good sphericity anddispersibility. It indicated that the KH-570was grafted successfully. The interfaceof core-shell microspheres was clear and the layer of PVP encapsulation was37nm.