Assessing micromechanical behaviour of PET cords in rubber matrix composites by laser Raman microscopy

The mechanical behaviour of PET cord-rubber composites has been investigated by adopting a multi-scale approach by combining standard tensile testing and laser Raman microscopy (LRM). Tensile tests were performed on cord-rubber composite and on its constituents to gain information on the mechanical response at the macro-scale. The behaviour at smaller scales was assessed by means of LRM, which has already been established as a technique that can yield values of stress or strain of reinforcement at the micro-scale. The effects of cord content, composite configuration and sample length have been examined. In particular, the efficiency of stress/strain transfer to the embedded cord has been evaluated and correlated to the micromechanical behaviour through the 'finite fibre length effect' observed at the macro-scale.