Polymer composites with short recycled glass fibres manufactured by vacuum infusion

Recycling glass fibre reinforced thermoset composites remains a challenge despite years of research in the field. Among the barriers for a successful recycling, the properties of the recycled materials and their application in new products represent the main ones. With a pyrolysis recycling process, clean glass fibres can be extracted and separated from the polymer matrix. In this paper, recycled glass fibres are incorporated in a new polymer composite structure using both virgin and recycled glass fibres. Recycled glass fibres have a Young’s modulus comparable to virgin glass fibres. The objective is to identify a composite lay-up using virgin and recycled glass fibres, and where the Young’s modulus of recycled fibres is beneficial for the resulting composites mechanical properties. To do so, a sandwich structure composite with virgin fibres on the outer layer and recycled fibres in the inside is designed and manufactured. In order to produce flat panels despite the short and random fibres, a manufacturing procedure ensuring a good dispersion of the fibres and controlling the thickness of the panel is developed. Panels are produced incorporating two different weight fraction of recycled glass fibres. The quality of the panels are characterized using microstructure observations, fibre porosity analysis and mechanical testing. Results shows that the sandwich composites have a low porosity content and achieves higher bending stiffness than a composite only made of unidirectional virgin glass fibres.