Interface and Interphase in Carbon Fibre-Styrene Butadiene Rubber (SBR) Composites

Abstract

The stress transfer capacity of carbon fibre-SBR interfaces is analysed in terms of interfacial shear strength and measured by means of a fragmentation test on single fibre composites. For all the cases studied, the experimental values of the interfacial shear strength are largely higher than theoretically expected. Such a result is explained by the existence near the fibre surface of an interfacial layer in which the polymer chain mobility is greatly reduced. Such an interfacial region of low mobility is pointed out by mechanical spectrometry on unidirectional composites at different fibre contents. This interphase could exhibit a pseudo-glassy behaviour and, in particular, an elastic modulus close to that of the elastomer in its glassy state whatever the temperature.

Key Words:

• fibre-matrix adhesion in composites
• stress transfer phenomenon
• fragmentation test on single fibre composites
• carbon fibre-rubber interface
• interphase.