Pultrusion of thermoplastic composites with mechanical properties comparable to industrial thermoset profiles

Pultruded thermoplastic composite profiles offer several advantages over their conventional thermoset counterparts, such as high impact toughness, recyclability, and smaller environmental footprint. However, thermoset profiles outperform thermoplastic composite profiles in terms of mechanical properties through high fiber volume fraction. The study is aimed at producing thermoplastic profiles with high content of reinforcing fibers, using preconsolidated tapes manufactured in-house from glass fiber/polypropylene commingled yarns with fiber content of 80 % by weight. The tapes were manufactured with the use of extrusion machine at speeds of 2, 5, and 8 m/min under the same temperature conditions. The strip profiles of 75 mm x 3.5 mm with fiber volume fraction of 50 % were produced of 76 tapes by thermoplastic pultrusion process at the pulling speed of 0.2 m/ min. The results of mechanical tests show that flexural strength and modulus of obtained thermoplastic profiles exceed minimal requirements to industrial thermoset profiles, constituting at least 488 MPa and 37 GPa respectively. Thermoplastic profile pultrusion from tapes made of commingled yarns does not require the use of a preheating chamber, produces profiles with 1 % porosity, and more energy efficient pultrusion process than pultrusion from commingled yarns.