Bond Strength of Co-Bonded Thermoplastic Leading Edge Protection (LEP): The Effect of Processing-Driven Interphase Morphology

Abstract

Integrated leading edge protection (InLEP) is a novel LEP method that involves co-bonding a tough thermoplastic to the blade shell of the wind turbine made of fiber-reinforced thermoset polymer. In the co-bonding process, as a result of the interdiffusion of the bonded thermoplastic and thermoset polymers, an interphase is formed between them. An important factor affecting the level of interdiffusion is the cure temperature. In this work, we investigate the influence of cure temperature on the interphase morphology and bond strength of ABS-polyester/glass and PC-polyester/glass hybrid composites. The hybrid composites are manufactured via vacuum-assisted resin transfer molding. Interphase morphology is observed and the interphase thickness is measured via optical microscopy. Bond strength is tested via climbing drum peel testing and subsequently, fractography analysis is carried out on the fractured samples. It was found that both the interphase thickness and bond strength decrease with an increase of cure temperature. The decrease in bond strength at high temperatures was accompanied by an increase in the extent of interfacial failure, while interphase failure at low temperatures promoted higher bond strength.