期刊
POLYMER
卷 50, 期 6, 页码 1541-1547出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.polymer.2009.01.036
关键词
Relaxation dynamics; POSS; Dielectric spectroscopy
资金
- National Science Foundation [DMR-0346435]
Segmental and normal mode dynamics in polyhedral oligomeric silsesquioxane (POSS)/poly(propylene oxide) (PPO) non-reactive and reactive nanocomposites were investigated using a broadband dielectric relaxation spectroscopy (DRS) over wide ranges of frequency and temperature. Three POSS reagents with varying side chain architecture were selected for the study: OctaGlycidyldimethylsilyl (OG), TrisGlycidylEthyl (TG) and MonoGlycidylEthyl (MG). Spectra of OG and TG show a segmental (alpha) process at lower frequency and a local (beta) relaxation at higher frequency, while MG displays only a local relaxation. Neat PPO has both segmental and normal mode (alpha(N)) process. In POSS/PPO non-reactive nanocomposites, the presence of OG and TG causes a decrease in the time scale of alpha(N) and alpha relaxation, while MG has no impact on the dynamics of PPO. Chemical reactions in POSS/PPO reactive nanocomposites lead to the formation of nanonetworks. Prior to the onset of reaction, POSS nanoparticles promote the motions of PPO chains, decrease the time scale of relaxation and give rise to thermodielectrically simple spectra. During the reaction, however, the network formation leads to spectral broadening and a gradual increase in the time scale of both segmental (alpha) and normal mode (alpha(N)) relaxation. A detailed account of the effects of structure, concentration and dispersion of POSS in the matrix, molecular weight of PPO, extent of reaction and temperature on the molecular origin, temperature dependence and spectral characteristics of relaxation processes in POSS/PPO nanocomposites is provided. (C) 2009 Elsevier Ltd. All rights reserved.
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