Conformational analysis and dielectric relaxation of polycarbosilanes and related materials


The conformational characteristics of poly(dimethylsilmethylene), poly(dimethylsilethene), poly(dimethylsilethane) and a related material, poly(2,2,5,5-tetramethyl-1-oxa-2,5-disilapentane), have been investigated using the method of molecular mechanics. In this method, a quantitative analysis of the factors affecting the nature and magnitude of the bond rotation potentials governing their conformational behaviour has been undertaken. Along with their structural data, the results obtained were employed to calculate a variety of conformationally-dependent properties for these polymers, including the characteristic ratio, the dipole moment ratio and the mean-square radius of gyration. In addition, the dielectric relaxation behaviour of two samples of poly(2,2,5,5-tetramethyl-1-oxa-2,5-disilapentane) with molar masses Mw = 28000 and Mw = 46000 respectively, have been studied as a function of temperature (179K-205K) and frequency (100-105Hz). Activation energies for the α-relaxation process and Davidson-Cole empirical distribution factors have been calculated.

Divisions: College of Engineering & Physical Sciences > School of Infrastructure and Sustainable Engineering > Chemical Engineering & Applied Chemistry
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Institution: Aston University
Uncontrolled Keywords: statistical weight,characteristic ratio,dipole moment ratio,Davidson-Cole relaxation,activation energies
Last Modified: 08 Dec 2023 08:27
Date Deposited: 25 Nov 2010 14:12
Completed Date: 1994-06
Authors: Elsby, David J.


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