Newly developed chloroprene rubber composites based on electron-modified polytetrafluoroethylene powder

Compatibility via chemical coupling between electron-modified polytetrafluoroethylene (PTFE) powder and poly-2-chlorobutadiene rubber is accomplished by activation of the radiation-induced carboxylic groups on the PTFE surface by zinc oxide. This is achieved both prior to and during reactive blending of zinc oxide with chloroprene rubber. Spectroscopic analysis of the reaction products reveals an increase in characteristic chloroprene absorption (approximate to 1660 cm(-1)) due to the stretching of the C=C bond. Microscopic observations suggest that the PTFE dispersion is considerably improved, while the state of interphase between the PTFE particles and the chloroprene rubber indicates enhanced compatibility. The increase in the cross-link density determined by Mooney-Rivlin plots provides indirect evidence for the existence of chemical coupling. PTFE-based chloroprene composite exhibits a significant increase in modulus due to the strong reinforcement effect of the modified PTFE powder. Finally, we propose an explanation of the coupling mechanism based on the chemical activation of carboxylic groups in the PTFE powder in the presence of zinc oxide. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.