Rubber elasticity study of polyurethane networks prepared by cyclotrimerisation crosslinking reaction of isocyanate groups

Abstract

The aim of this contribution was to study the rubber elasticity of dry and swollen networks obtained by cyclotrimerization crosslinking reaction of isocyanate groups located at a linear telechelic network precursor. Telechelic diisocyanates were prepared in the undiluted state from 2,4-tolylene diisocyanate, α,ω,dihydroxypoly(oxypropylenes) and different contents of the monool component 2-(2-metoxyetoxy) ethanol. The network synthesis proceeded in a bulk. Detailed network topology was calculated by the theory of branching processes. The equilibrium swelling degree of prepared samples was related to the parameters, which are experimentally accessible for a network arising from an end-linking process using the Flory-Rehner theory. The experimental data for network modulus were compared with those arising from the "affine" model, "phantom' model" and the model of constrained junctions.