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Glass transition temperature versus conversion relationship in the polycyclotrimerization of aromatic dicyanates
Author(s) -
Lin RongHsien,
Su AnChung,
Hong JinnLung
Publication year - 2000
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/(sici)1097-0126(200004)49:4<345::aid-pi374>3.0.co;2-d
Subject(s) - glass transition , materials science , polymer science , polymer chemistry , chemistry , composite material , polymer
Abstract Comparisons of the effectiveness of different theoretical equations to fit various sets of experimental T g versus conversion data are made. Among all the theoretical expressions for the T g versus conversion relationship, one‐parameter equations give excellent fitting to the experimental data. The values of parameters obtained thereby can be merely considered as fitting parameters without realistic physical meanings. Mean‐field crosslink density and elastically effective crosslink density are derived and applied to the corresponding theoretical equations for comparison in our aromatic dicyanate systems. The Hale–Macosko–Bair (HMB) equation and the so called original DiBenedetto equation combining the mean‐field crosslink density, rather than elastically effective crosslink density, are applied with success to fit experimental data; hence the parameter values obtained by this method are more consistent with the original designated physical meanings within the corresponding theoretical frameworks. This is attributed to the fact that the inelastic intramolecular loops may still contribute to the increase in T g , although they make no contribution to the gelation. An expression relating the effect of inelastic intramolecular loops on the gel fraction is also derived. Relationships between the parameters in different theories are discussed. © 2000 Society of Chemical Industry