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首页> 外文期刊>Journal of Non-Crystalline Solids: A Journal Devoted to Oxide, Halide, Chalcogenide and Metallic Glasses, Amorphous Semiconductors, Non-Crystalline Films, Glass-Ceramics and Glassy Composites >Glass transition and segmental dynamics in poly(dimethylsiloxane)/silica nanocomposites studied by various techniques
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Glass transition and segmental dynamics in poly(dimethylsiloxane)/silica nanocomposites studied by various techniques

机译：通过各种技术研究聚二甲基硅氧烷/二氧化硅纳米复合材料的玻璃化转变和分段动力学

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We report new results on segmental dynamics and glass transition in a series of poly(dimethylsiloxane) networks filled with silica nanoparticles prepared by sol-gel techniques, obtained by differential scanning calorimetry (DSC), thermally stimulated depolarization currents (TSDC), broadband dielectric relaxation spectroscopy (DRS) and dynamic mechanical analysis (DMA). The nanocomposites are characterized by a fine dispersion of 10 nm silica particles and hydrogen bonding polymer/filler interactions. The first three techniques indicate, in agreement with each other, that a fraction of polymer in an interfacial layer around the silica particles with a thickness of 2-3 nm shows modified dynamics. The DSC data, in particular measurements of heat capacity jump at T-g, are analyzed in terms of immobilized polymer in the interfacial layer. The dielectric TSDC and DRS data are analyzed in terms of slower dynamics in the interfacial layer as compared to bulk dynamics. We employ a special version of TSDC, the so-called thermal sampling (TS) technique, and provide experimental evidence for a continuous distribution of glass transition temperatures (T-g) and molecular mobility of the polymer in the interfacial layer, which is consistent with the DRS data. Finally, DMA results show a moderate slowing down of segmental dynamics of the whole polymer matrix (increase of glass transition temperature by about 10 K as compared to the pure matrix). (c) 2007 Elsevier B.V. All rights reserved.
机译：我们报告了一系列动态变化和玻璃化转变的一系列聚二甲基硅氧烷网络中充满了由溶胶-凝胶技术制备的，通过差示扫描量热法（DSC），热激发的去极化电流（TSDC），宽带介电弛豫获得的二氧化硅纳米颗粒光谱（DRS）和动态力学分析（DMA）。纳米复合材料的特征是10 nm二氧化硅颗粒的精细分散和氢键键合的聚合物/填料相互作用。前三种技术彼此一致地表明，在二氧化硅颗粒周围的界面层中，厚度为2-3 nm的聚合物部分显示出动态变化。根据界面层中固定的聚合物，分析了DSC数据，特别是在T-g处的热容量跃迁的测量。与界面动力学相比，介电TSDC和DRS数据是根据界面层中较慢的动力学进行分析的。我们采用TSDC的特殊版本，即所谓的热采样（TS）技术，并为玻璃化转变温度（Tg）和界面层中聚合物的分子迁移率的连续分布提供了实验证据，这与DRS数据。最后，DMA结果显示整个聚合物基质的段动力学适度减慢（与纯基质相比，玻璃化转变温度提高了约10 K）。 （c）2007 Elsevier B.V.保留所有权利。

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