两步反相微乳液法原位制备纳米SiO_2/聚甲基丙烯酸甲酯复合微粒

IN SITU PREPARATION OF NANO-SILICA/ POLYMETHYLMETHACRYLATE COMPOSITE PARTICLES BY TWO-STEP INVERSE MICROEMULSION METHOD

采用两步反相微乳液法原位聚合制备纳米SiO2/聚甲基丙烯酸甲酯(polymethylmethacrylate,PMMA)复合微粒。首先,通过混合2 个分别增溶有2种反应物的微乳液,制备纳米SiO2粒子;然后,向混合后的微乳液中滴加单体及引发剂,通过单体的原位聚合反应得到SiO2/ PMMA复合微粒。通过相图研究:确定了微乳液法制备复合微粒时初始组分的用量。通过透射电子显微镜、红外光谱、热重分析、X射线光电 子能谱等手段对复合微粒进行了表征。结果表明:聚合后的PMMA包覆在SiO2表面,复合微粒的平均粒径为30nm,分散性良好。复合微粒 中不能被抽提出来的聚合物占10.08%,这部分聚合物以Si—O—C键形式接枝在SiO2表面。

Nano-silica/polymethylmethacrylate (PMMA) composite particles were in situ prepared by two-step inverse microemulsion method. Silica nanoparticles were prepared firstly by mixing two water/oil inverse microemulsion systems and then the monomer MMA were dropped into the mixed microemulsion system. The nano-silica/PMMA composite particles were obtained by in situ polymerisation. The initial dosages of all compositions for preparing composite particles were determined by phase diagram. The nano-silica/PMMA composite particles were characterized by transmission electron microscope, thermogravimetry, Fourier transform infrared spectroscope and X-ray photoelectron spectroscope. The results show that PMMA is coated on the surface of silica after polymerisation and the composite particles have a good dispersibility with an average diameter of 30 nm. There is 10.08% polymer released in the composite particles, which can not be extracted by acetone for a long time and is grafted on the surface of silica by Si-O-C bonds.