Étude de la gélification d'un système triol/diacide/monoacide avec effect de substitution sur le triol
✍ Scribed by Durand, Dominique ;Bruneau, Claude-Marcel
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1977
- Weight
- 490 KB
- Volume
- 178
- Category
- Article
- ISSN
- 0025-116X
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✦ Synopsis
Abstract
Using a new general formulation of Flory's gelation criterion, a critical transition equation is derived for the trimethylolpropane (2,2‐bis(hydroxymethyl)‐1‐butanol)/adipic acid/lauric acid system having a substitution effect on the hydroxyl groups of the triol. The successive reactivity of the hydroxyl groups present in the trimethylolpropane has been formulated by the study of the condensation of the triol with the monoacid, lauric acid. From GPC measurements of the reaction medium for various degrees of conversion, the distribution curves of the different molecular species are plotted. Examination of these distribution curves has shown a non‐equireactivity of the sites of the polyol, which may be assigned to a positive substitution effect. Comparison of experimental distribution curves with the results of the kinetic analysis allows one to quantify the substitution effect. The gelation equation shows that a positive substitution effect on the hydroxyl groups of the triol decreases the extent of reaction necessary for the gelation. The difference between the experimental gelation curves and the theoretical curves with substitution effect may be assigned to intramolecular reactions.