摘要
采用分散聚合方法制备了聚二乙烯基苯微球 ,研究了引发剂、稳定剂、单体 溶剂比例和溶剂种类对微球粒径及其分布的影响 ,在适当的条件下可以得到平均粒径较大、粒径分布较窄的微球 .用红外光谱法研究了聚合物微球内稳定剂、悬挂双键以及对位和间位二乙烯基苯含量随聚合过程的进行发生的变化 .测得的微球TG曲线表明 ,聚合物微球具有良好的热稳定性 .
Highly cross-linked and narrow dispersed poly (divinylbenzene)(PDVB) microspheres were prepared by the dispersion polymerization of commerical divinylbenzene using acetonitrile as solvent in the presence of 2, 2'-azobis(2-methylpropionitrile) (AIBN) initiator and polyvinylpyrrolidone (PVP) stablizer. The particle average diameter and the particle size distribution were determined by SEM. Narrow dispersed microspheres with diameters between 3 and 5 mum depending on the conditions were produced. The effects of concentrations of initiator and stabilizer, solvent variety, ratio of monomer and solvent on particle average diameters and particle size distributions were investigated. Based on an optimal codition, larger particle size and narrower dispersed microspheres can be synthesized, the particle average diameter is 3.95 mum and the coefficient of particle size distributions (PSD) is 0.106. The time dependence of stabilizer (PVP) content, residual double-bonds and the relative ratio of pares-and metes-divinylbenzene in the microspheres were studied by IR psectra. The ratios of characteristic absorbance of components changing with time showed the change of each component in the polymerization product. Monomer conversion was determined gravimetrically after washing residual monomers from the raw particle slurries and drying under vacuum. It is revealed from the conversion-time curve that the polymerization reaction is almost complete in 12 h. The content of residual double-bonds in the microspheres was determined by the reaction with Br-2/H2O, then titrated by 0.1 mol/L criterion NaOH solution. The microspheres produced by dispersion polymerization as mentioned above contain(1.7 +/- 0.5) mol/g residual double-bonds. The thermostability of microspheres were determined by TG. The starting temperature of decomposition is above 400degreesC,the fastest decomposing temperature is 461.6degreesC, showing that PDVB microspheres have high thermo-stability.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2004年第3期410-414,共5页
Acta Polymerica Sinica
基金
国家自然科学基金资助项目 (基金号 2 0 0 740 17
2 0 0 2 740 18)
关键词
聚合物微球
二乙烯基苯
合成
分散聚合
热稳定性
粒径分布
dispersion polymerization
divinylbenzene
particle size distribution
polymer microspheres
