乳液聚合法制备纳米SiO_2/PMMA复合粒子及其表征(英文)

Preparation and Characterization of Nano-SiO_2/PMMA Composite Particles by Emulsion Polymerization

利用可聚合乳化剂在纳米SiO2表面进行乳液聚合,成功制备出了具有核壳结构的纳米SiO2/PMMA复合粒子,并通过FTIR、TEM、XPS和TGA分析了其粒子形态和包覆效果。结果表明:偶联剂MPTMS已成功接到了改性后的纳米SiO2的表面,其谱图呈现了PMMA和纳米SiO2的复合结构而没改变原来纳米SiO2结构。复合粒子的粒径约50～100 nm,形态具有外层较浅内层较深的核壳结构。XPS分析表明,SiO2被PMMA包覆后,其表面的Si含量降为1.29%,用甲苯对纳米SiO2/PMMA复合粒子抽提后,Si含量增加到3.50%。基于索氏抽提实验和TGA分析,PMMA与SiO2比(fp)、PMMA对SiO2接枝率(fr)和PMMA的有效接枝率(fe)分别为95.8%、63.4%和67.1%。

The nano-SiO2/PMMA composite particles with core-shell structure were prepared by emulsion polymerization on the surface of nano-SiO2 using a polymerizable emulsifier(SE-10).The particles morphology and encapsulation effect were characterized by FTIR,TEM,XPS and TGA.The results indicated that the coupling agent MPTMS was grafted to the surface of modified nano-SiO2 and the spectra presented the composite structure of PMMA and nano-SiO2 without changing the structure of original nano-SiO2.The diameter of the composite particles was about 50-100 nm,the morphology had the core-shell structure with light outer part and dark inner part.The XPS analysis exhibited that the Si content on the surface decreased rapidly to 1.29% after nano-SiO2 was encapsulated by PMMA.After the nano-SiO2/PMMA composite particles were extracted by toluene,the Si content increased to 3.50%.Basing on the Soxhlet extraction experiments and TGA result,the ratio of PMMA to original nano-SiO2(fp),the grafting ratio of PMMA to original nano-SiO2(fr) and efficiency grafting ratio of PMMA(fe) were respectively about 95.8%,63.4% and 67.1%.