Thermo-oxidative induced shrinkage in Organic Matrix Composites for High Temperature Applications: Effect of fibre arrangement and oxygen pressure

The present paper focuses on thermo-oxidative induced chemical shrinkage in HTS/TACTIX carbon/epoxy Organic Matrix Composites for High Temperature Applications, providing an insight on the effect of the fibre arrangement and of the oxygen pressure as an accelerating parameter. In particular, measurement of matrix shrinkage in composites surface is carried out by Interferometric Microscopy for virgin samples (initial state) and for samples aged under oxygen pressure and air at atmospheric pressure: some discussion about the “structural” effect (arrangement of fibres, fibre volume fraction) on matrix shrinkage development of unidirectional composites is provided; a link between the measured surface matrix shrinkage and the evolution of the surface elastic indentation modulus measured in pure resin samples can be clearly established: moreover, it is shown that matrix shrinkage development in composites can be conveniently accelerated by the employment of oxygen pressure, as in pure resin systems.