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The water relaxation in polymers containing the amide group
Author(s) -
Pezzin Giovanni
Publication year - 1978
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760181014
Subject(s) - polyamide , amide , polymer , relaxation (psychology) , glass transition , amorphous solid , materials science , activation energy , polymer chemistry , bound water , group (periodic table) , chemistry , crystallography , organic chemistry , composite material , molecule , psychology , social psychology
The low temperature water relaxation of synthetic polymers containing the amide group is usually attributed to the motion of a water‐polymer complex in the amorphous region. According to Puffr and Sebenda the complex is formed by water and amide group in the stoichiometric ratio 1.5. Elastin, an insoluble protein of vessels and ligaments, seems the ideal polymer for testing the model, being practically free of polar side groups and having a glass transition at 200°C, so that its “water peak” can be easily investigated. Calorimetric investigations show that the molar ratio for “bound water‐amide group” is indeed 1.5, as predicted by the model. The activation energy of the “water peak” is very close, for the “dry” protein, to that of nylons, but it decreases with increasing hydration to a limit of 9 kcal/mole. The results give additional support to the traditional interpretation of the polyamide beta relaxation and to the Puffr and Sabenda model for the interaction of water and amide groups in synthetic polymers.