Effect of polypropylene on the mechanical properties and water absorption of carbon-fiber-reinforced-polyamide-6/polypropylene composite

Lightweight materials are becoming important in many industries, such as automotive, portable electronics, and so on. Polymer blends containing polyamide-6 (PA6) and polypropylene (PP) have been widely applied for weight reduction and low water absorption. It is well known that PA6 has a high affinity for water, and its mechanical properties and dimensional stability are often significantly affected by the absorption of water, whereas PP is characterized by its moisture resistance, low density and cost. The aim of our research was to investigate the effect of PP on the weight reduction, water absorption, dimensional stability and mechanical properties of carbon-fiber-reinforced PA6 composite in order to find a proper way to improve carbon-fiber-reinforced PA6 widely used in industry especially for high humidity or underwater applications. We assessed the mechanical properties by a tensile test and the microstructure by scanning electron microscopy for composites with and without water saturation. After being saturated with water, the composites with PP showed better ultimate tensile strength, elastic modulus, elongation, density for weight reduction and dimensional stability than the composite without PP.