The effect of fibre length and matrix modification on the fire performance of thermoplastic composites: The behaviour of PP as an example of non-charring matrix

Abstract

The fire performance of fibre-reinforced polypropylene (PP) was investigated with respect to fibre length and modification of the matrix. Fibre lengths of 3 mm, 12 mm, and continuous fibres were used as reinforcements. E-glass continuous fabrics were melt impregnated with PP and consolidated via compression moulding. E-glass fibre-reinforced PP pellets of 3 and 12 mm were compression moulded. Cone calorimetry tests with incident radiant fluxes of 20, 30 and 35 kW m−2 were used to investigate the fire properties of PP glass fibre composites. Results showed that continuous glass fibre reinforced PP exhibits the best fire performance at 20 kW m−2, while 3-mm fibre has the best performance at 35 kW m−2; 12-mm fibre-reinforced PP exhibitedthe lowest performance in comparison with 3-mm and continuous glass fibre reinforcement. Melic-anhydride (MA)-modified PP was found to increase the heat release rate (HRR) by up to 44% and time to ignition by up to 10% depending on the heat flux applied in comparison with unmodified PP. The glass fibre-reinforced composite made with MA-modified PP has 5–12% lower mean HRR and similar time to ignition in comparison with glass fibre composite made by unmodified PP. This suggests improved fibre adhesion plays a role of the fire performance of glass fibre-reinforced PP.

Directly bonded single lap joints of SiCp/AA2124 composite with glass fiber-reinforced polypropylene: Hole drilling effects on lap shear strength and out-of-plane impact response

“…26,27 Furthermore, thermoplastics are replacing thermosets as matrix in composites owing to their superior impact toughness. 28,29 Consequently, especially in the automotive and aerospace industries, 30,31 the interest for thermoplastic-based composites has grown consistently. This increasing demand generally focuses on glass fiber reinforced composites.…”