The glass transition temperature for non-gaussian network polymers
作者:
JohnM. Charlesworth,
期刊:
Journal of Macromolecular Science, Part B
(Taylor Available online 1987)
卷期:
Volume 26,
issue 1
页码: 105-133
ISSN:0022-2348
年代: 1987
DOI:10.1080/00222348708248061
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The influence of crosslinking and copolymerization on the glass transition temperature, Tg, of a range of diepoxide-diamine network polymers is examined. It is established that existing theories relating Tgto the level of crosslinking are inexact above a crosslink concentration of approximately 0.5 mole dm−3. To account for this deviation, the thermodynamic treatment of the glass transition is modified to take into consideration a non-Gaussian spatial distribution of chain segments and the steric restrictions upon movement of segments in the vicinity of junctions. The resulting equation-involving two empirical parameters, and the number of rotatable bonds between junctions—is shown to adequately explain data for the diglycidylethers of bisphenol A and butanediol, crosslinked with benzidine/aniline and 1,8-oc-tanediamine/n-butylamine mixtures. The behavior of networks prepared from α, ω-alkyldiamines containing from 2 to 36 methylene units can be predicted provided it is assumed that
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