Physical nature of complex structural relaxation in polysiloxane - PMpTS: alpha and alpha' relaxations
Physical nature of complex structural relaxation in polysiloxane - PMpTS: alpha and alpha' relaxations
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聚硅氧烷中复杂结构弛豫的物理性质 - PMpTS：α 和 α 弛豫
DOI：
10.1016/j.polymer.2006.05.065
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发表时间：
2006
期刊：
影响因子：
4.6
通讯作者：
G. Meier
中科院分区：
文献类型：
--
作者：
A. Patkowski;J. Gapiński;T. Pakuła;G. Meier
用动态光散射法研究了三种相对分子质量的聚甲基对甲苯基硅氧烷(PMPTS)聚合物的结构松弛过程。观察和研究了两个松弛过程：通常的α和一个附加的慢的α‘。与结构松弛相反，我们发现在曲线图T-Tg中，所有分子量的α过程的松弛时间不会崩溃到一条曲线。对其中一个样品的光散射相关函数与通过机械弛豫、介电光谱和计算机模拟获得的相应函数进行了比较。模拟结果表明，大多数探针的关联函数(光学各向异性、偶极矩、链键、密度)都包含双峰分布，即α驰豫和慢(α‘)过程，这与实验观测一致。
Structural relaxation processes in poly(methyl-para-tolyl-siloxane) (PMpTS) polymers of three molecular weights were studied using dynamic light scattering. Two relaxation processes: the usual α and an additional slow one α′ were observed and studied as function of temperature and molecular weight. Contrary to the structural relaxation, we find that in a plot T–Tgthe relaxation times for the α′ process for all molecular weights do not collapse to a single curve. For one of the samples the light scattering correlation functions were compared with the corresponding functions obtained by means of mechanical relaxation, dielectric spectroscopy and computer simulations. The simulations show that the bimodal distribution, i.e. the α relaxation and the slow (α′) process are contained in the correlation functions of most of the probes (optical anisotropy, dipole moment, chain bond, density) in agreement with experimental observations.