【摘要】 利用偶氮型聚乙二醇大分子引发剂(VPE)引发苯乙烯进行无皂乳液聚合,制得了颗粒形态规整、单分散性较好的共聚物纳米微球。通过透射电子显微镜(TEM)和激光光散射(LLS)对微球的形态、粒径大小与分布进行了表征,同时考察了大分子引发剂VPE用量对聚合物纳米微球的粒径和聚合物乳液粘度的影响。实验结果表明:当苯乙烯的浓度固定在0.385mol/L时,随着VPE的浓度从1.2mmol/L增加到4.8mmol/L,聚合物纳米微球的粒径从178nm减少到70nm,而聚合物乳液的黏度相应从1.93mPa.s增加到2.17mPa.s,说明微球粒径在一定范围内可控。由嵌段共聚物的结构可推测该聚合物纳米微球的形成机理与传统乳液聚合体系不同,属于自组装成核,形成的微球具有核壳结构,这提供了一种简便制备嵌段共聚物纳米微球的方法。更多还原

【Abstract】 The monodispersed nanospheres with uniform morphology and a core-shell structure were prepared by emulsifier-free emulsion polymerization of styrene using azo-type poly(ethylene glycol) macroinitiator(VPE) as radical initiator and dispersion stabilizer agent in water.The morphology and size distribution of the block copolymer nanospheres were characterized by means of laser lighter scattering(LLS) and transmission electron microscopy(TEM).Influences of the macroinitiator concentration on the particle size and emulsion viscosity were investigated.The result showed that particle size of the nanospheres decreased from 178 nm to 70 nm with the macroinitiator concentration increased from 1.2 mmol/L to 4.8mmol/L.Also,the emulsion viscosity increased from 1.93 mPa·s to 2.17 mPa·s with the macroinitiator concentration increased from 0.8mmol/L to 2.4mmol/L in feed.The particle size of the nanospheres can be controlled in same range by changing VPE concentration.The formation mechanism of the block copolymer nanospheres is different with conventional emulsion polymerization system.This is a new method for preparation of block copolymer nanosphere.更多还原