聚醋酸乙烯酯大分子单体与苯乙烯的分散共聚

以聚醋酸乙烯酯(PVAc)大分子单体为分散稳定剂,通过分散聚合制得了PVAc接枝聚苯乙烯(PVAc-g-PSt)复合微球。用激光光散射和透射电子显微镜对PVAc-g-PSt复合微球的粒径及形态进行了表征,考察了外部聚合因素(聚合时间、介质的极性、聚合温度和振荡转速)对PVAc-g-PSt复合微球的粒径及其分布的影响。用核磁共振和X射线光电子能谱对PVAc-g-PSt复合微球的结构及组成进行了分析,分析结果显示,所得的接枝聚合物是以PVAc为壳、PSt为核的核壳结构复合微球。根据PVAc-g-PSt复合微球表面组成的分析,计算出了典型配方(c(PVAc)=0.001mol/L、c(St)=0.1mol/L、c(偶氮二异丁氰)=0.001mol/L、n(PVAc)∶n(St)=0.01、x(偶氮二异丁氰)=0.1%、乙醇4mL、水1mL、60℃、160r/min、24h)条件下稳定每个PVAc-g-PSt复合微球表面的PVAc接枝链数为1.6×103。

Dispersion Copolymerization of Poly(Vinyl Acetate)Macromonomer with Styrene

Poly(vinyl acetate)(PVAc)grafted polystyrene(PSt)composite microspheres(PVAc-g-PSt)were prepared by dispersion copolymerization of styrene with PVAc macromonomer.The latter acted as dispersion stabilizer.Morphology and particle size of PVAc-g-PSt were studied by means of TEM and laser light scattering(LLS).Effects of polymerization time,media polarity,polymerization temperature and vibrating rotary speed of constant temperature water bath on particle size and size distribution of PVAc-g-PSt were investigated.Molecular structures and composition of PVAc-g-PSt were studied by means of ~1H NMR and XPS.The PVAc-g-PSt is of core-shell structure with PSt as core and PVAc as shell.Under typical condition:c(PVAc)0.001 mol/L,c(styrene)0.1 mol/L,c(azobisisobutyronitrile)0.001 mol/L, n(PVAc) ∶n(styrene)0.01,x(azobisisobutyronitrile)0.1%,ethanol 4 mL,water 1 mL,60 ℃,160 r/min and 24 h,chain number of PVAc grafted on surface of each PVAc-g-PSt composite microsphere was 1.6×10~3.