FRAGILITY AND NONLINEARITY IN POLYMETHYL(ALPHA-N-ALKYL)ACRYLATES

In this work, the fragility indices, m, of some new polymers from the polymethyl(alpha-n-alkyl)acrylate family, with 3, 5, or 8 carbons in t he side chain, were determined with the method proposed by Bohmer. We have found that the value of the fragility index decreases as the leng th of the lateral chain increases. We also confirm a previous work in which we found a critical length of the alkyl chain which separates tw o types of dependence, identified by different relaxation parameters. The correlations between the ms and the Narayanaswamy parameter are al so investigated. (C) 1998 Elsevier Science B.V. All rights reserved.