【摘要】 为制备出规则球形的聚丙烯腈(PAN)纳米粒子,探究水溶性较大的单体的细乳液聚合机理,分别采用过硫酸钾(KPS)、偶氮二异丁腈(AIBN)和双氧水/L-抗坏血酸(H2O2/LAA)氧化还原引发剂进行丙烯腈(AN)的细乳液聚合。通过乳液外观的变化比较了三种引发剂对聚合过程的影响,对比了三种PAN纳米粒子的形态、粒径和结晶情况。结果发现;采用热引发剂时,由于AN的水溶性增大,单体扩散明显,所制备出的PAN纳米粒子为不规则颗粒;而采用氧化还原引发剂能够获得规则球形的PAN纳米粒子。说明了水溶性较大的单体进行细乳液聚合时,温度是影响液滴成核主导地位的关键因素;均相成核是造成PAN颗粒表面结晶进而导致PAN粒子形状不规则的主要原因。更多还原

【Abstract】 In order to prepare spherical polyacrylonitrile(PAN) nanoparticles via miniemulsion polymerization and explore the mechanism of miniemulsion polymerization of monomers with relative high water solubility, different initiators including potassium persulfate(KPS), azobisisobutyronitrile(AIBN) and hydrogen peroxide/L-ascorbic acid(H2O2/LAA) redox pair were used in the study of acrylonitrile(AN) miniemulsion polymerization process. The effects of these initiators on the miniemulsion polymerization process were compared via emulsion appearance together with morphology and crystallinity of the resulted PAN nanoparticles. The results show that the high water solubility of the monomer leads to higher diffusivity when the temperature increases, which results in the PAN nanoparticles with crumpled appearance when prepared using thermal initiators, however, the PAN nanoparticles prepared using redox initiator are spherical in shape. This result indicates that temperature is a key parameter that affects the nucleation process of miniemulsion polymerization of monomers with relative high water solubility, and homogenous nucleation is the main factor leads to surface crystallization, which results in the irregular morphology of PAN nanoparticles.更多还原