Collective effects during connector chain extraction in the adhesion of elastomers

¹ Laboratoire de Physico-Chimie Théorique, ESA CNRS 7083, ESPCI, 10 rue Vauquelin, 75231 Paris Cedex 05, France
² Department of Chemical Engineering, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218-2689, USA

Received: 30 March 1998
Accepted: 17 June 1998

Abstract

We use the one-dimensional (1D) and the two-dimensional (2D) Self-Consistent Field (SCF) approximations to study the extraction of grafted connector chains from a molten matrix modeling a weak cross-linked elastomer. Evidence is found for collective effects due to aggregation of extracted chain sections. For monodisperse grafted connector chains, the 1D analysis indicates that spontaneous extraction of connector chains occurs at a characteristic gap size H^* that depends on the connector chain degree of polymerization and grafting density, while the 2D analysis shows that aggregates formed in the air gap exhibit a rich structural hierarchy. A 1D analysis of the case of bimodal connector chains reveals a more complex two-stage extraction process, in which the extraction of the shorter chains induces the partial extraction of the longer ones.