Exploring the potential for vacuum assisted oven consolidation (VAOC) of natural fibre reinforced thermoplastic sheets (NFRTS)

Fibre reinforced plastics are being increasingly used in automotive, aerospace, marine, sporting and domestic industries. Considerable research has been carried out on natural fibres as reinforcements. They are obtained from renewable resources, possess higher stiffness per unit mass compared to glass fibres and are biodegradable. Significant opportunities exist in the industry to make the manufacturing of complex shaped (e.g. including. single or double curvature) composite parts more efficient using natural fibre reinforced thermoplastics with industrially accepted thermomechanical properties. Part geometry, size, processing time and scale of production are the key factors affecting tooling costs. This paper extends our previous work on vacuum assisted oven consolidation (VAOC) of natural fibre reinforced thermoplastic sheets (NFRTS). It involves comparisons of the manufacturing cycles and reinforcements used so far. In this work flax fibre reinforcement was selected because of its superior impact resistance, tensile strength, stiffness and low density as compared to other natural fibres. The main thermoplastic matrix used was polypropylene due to its availability as sheets, lower melting point and a higher melt flow rate compared to other thermoplastics.