Mechanical, water absorption, and aging properties of polypropylene/flax/glass fiber hybrid composites

This work investigates the mechanical and aging properties of flax/glass fibers reinforced polypropylene hybrid composites. The mechanical properties as a function of reinforcement content show that adding glass fiber to polypropylene/flax composites improves tensile modulus and strength as well as impact resistance and hardness, but has negligible effect on strain at yield and elongation at break. Water uptake at 85℃ and variations in mechanical behavior are determined after water, thermal, and accelerated UV aging tests. The results indicate that glass fibers enhance water resistance of polypropylene/flax composites. Thermal aging at 85℃ reveals that irrespective of filler type and content the composites are thermally resistant. According to accelerated UV aging tests, the presence of glass fiber accelerates the degradation of the polypropylene matrix, but flax fiber can protect the composites. Finally, a partial least-squares model is built to correlate the composite composition to the properties of aged and unaged specimens.