分步投料过程对聚苯乙烯纳米粒子粒径的影响

在苯乙烯的微乳液聚合体系中,以十二烷基硫酸钠为乳化剂,聚合采用单体的分阶段批量加料和微分-批量方式:第1部分单体采用批量或滴加形式让其聚合一段时间,然后将第2部分单体批量加入并继续聚合一段时间.采用动态激光散射法和透射电子显微镜等方法对粒子的尺度和形态进行分析和标定.在特定条件下,探讨了第一阶段的单体用量、引发剂相对量、乳化剂相对用量等因素对粒子的粒径的影响.结果证明,在乳化剂用量大幅降低的情况下,采用分阶段批量加料方式能够获得粒径＜40nm的聚苯乙烯(PS)纳米粒子,并且,采用微分-批量加料方式可以进一步降低PS纳米粒子的粒径,其粒径基本＜30nm.

Affecting the size of polystyrene nanoparticles by adding monomer in two stages

In a microemulsion polymerization system of styrene using sodium dodecylsulfate(SDS) as emulsifier,the monomer was divided into two parts and added by two following routes.For the one,the two parts of monomer was separately added in batch(batch and batch method).For the other,the first part of monomer was slowly dropped and the second part of monomer was poured collectively.The size and morphology for the resulting polystyrene(PS) nanoparticles were analyzed by means of dynamic light scattering method and transmission electron microscopy.Basing on an analysis about the polymerization system and processes,the influencing factors on the particle size including amount of monomer added in stage 1,relative amount of initiator and emulsifier were investigated.It was proved that PS nanoparticles with diameter smaller than 40 nm can be obtained as adopting the batch and batch method and especially,the size of PS nanoparticles can be further decreased and they had smaller diameter than 30 nm under a lower level of emulsifier.