期刊
JOURNAL OF APPLIED POLYMER SCIENCE
卷 100, 期 4, 页码 2684-2696出版社
WILEY
DOI: 10.1002/app.22849
关键词
isotactic polypropylene; silica; nanocomposites; tensile properties; thermal properties; morphology
In the present study two series of isotactic polypropylene (iPP)/SiO2 nanocomposites containing 1, 2.5, 5, 7.5, and 10 wt % SiO2 nanoparticles were prepared by melt-mixing on a twin-screw corotating extruder. In the first series untreated fumed silica nanoparticles were used, whereas in the second nanoparticles were surface-treated with dimethyldichlorosilane. hi both cases, the average size of the primary nanoparticles was 12 nm. Tensile and impact strength were found to increase and to be affected mainly by the type and content of silica nanoparticles. A maximum was observed, corresponding to samples containing 2.5 wt % SiO2. These findings are discussed in light of the SEM and TEM observations. By increasing the amount of nanoparticles, large aggregates Of fumed silica could be formed, which may explain the reduction of mechanical properties with higher concentrations of SiO2. However, it was found that surface-treated nanoparticles produced larger aggregates than did those derived from untreated nanoparticles, despite the increased adhesion of the iPP matrix, as was postulated from yield strength. This behavior negatively affected mechanical properties. In addition, an effort was made to determine if toughening theories, mainly the critical interparticle distance for rubber toughening or composites, also might be applicable in nanocomposites. From DSC measurements it was demonstrated that silica nanoparticles acted as effective nucleating agents, increasing the crystallization rate and the degree of crystallinity of iPP. (c) 2006 Wiley Periodicals, Inc.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据