Experimental characterisation of recycled (glass/tpu woven fabric) flake reinforced thermoplastic composites

Recycling of continuously reinforced thermoplastic composites (TPC) has a substantial prospect at present and in future due to its increasing availability and rapidly growing application regime. This study focusses on the first steps in using TPC process scrap on a scale in which its maximum potential can be utilised. It entails the mechanical response viz. elastic properties and strength of the flake reinforced plates under uniaxial tension. The plates were manufactured by compression moulding of flakes made of woven glass fabric reinforced thermoplastic polyurethane (TPU), oriented randomly within the plate. The randomness in the orientation of the flakes is evident from the observed in-plane isotropic behaviour in the experiments. Failure is in most cases dominated by the matrix and changes its path to avoid the flakes. The failure surface observation revealed regions of good and also regions of poor fibre-matrix as well as flake- matrix adhesion. Different classes of flake sizes were used to produce plate samples. The relationship between the flake size and mechanical properties were not statistically significant due to the similarities observed in the size distribution between the different classes of flakes used. The measured strength and stiffness values are compared with existing values and analytical results. The analytical results for stiffness and strength were found to be close to the measurements by 8% on average, which shows a fairly good agreement of the idealised theory where the effect of interactions between reinforcements are not included.