差示扫描量热法
纳米复合材料
聚合物
吸附
阿累尼乌斯方程
材料科学
动力学
聚苯乙烯
聚合物纳米复合材料
化学工程
分子动力学
活化能
高分子化学
化学
复合材料
热力学
物理化学
计算化学
物理
工程类
量子力学
作者
Jintian Luo,Yuhang Luo,Ben Tong,Houkuan Tian,Yuhui Yang,Biao Zuo
摘要
The dynamics of polymer nanocomposites varies depending on the physics and chemistry at the polymer-nanoparticle interface. The physical aging of the nanocomposites is accelerated or retarded based on interfacial interactions and the state of polymer adsorption at the interfaces. In this study, we investigated the aging kinetics of silica-polystyrene nanocomposites using differential scanning calorimetry, focusing on the effect of local conformations of chains adsorbed on the nanofiller surface. The results show that the temperature dependence of the aging rate follows a Vogel-Fulcher-Tammann relationship at high temperatures, whereas it exhibits an Arrhenius-like behavior below a characteristic temperature (Tc). Notably, at T < Tc, the aging rate decreases with increasing loop height of the chains adsorbed on the filler surface, but the activation energy remains unchanged. We proposed that the suppression of the aging rate at T < Tc is likely related to an increase in the length scale over which the slow interfacial dynamics can propagate due to the increased topological interactions between the chain loops of a larger size and the free chains in the matrix. The increased packing frustration occurring at the filler surface occupied by the larger loops might also contribute to the decreased aging rate.
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