Fatigue life and damage evaluation of Glass Fiber Reinforced Unsaturated Polyester Composite Materials Based on recycled Polyethylene terephthalate (rPET)

Abstract

Abstract Waste polyethylene terephthalate (PET) in the atmosphere creates an environmental concern. The use of waste PET as a matrix in a composite lowers the cost and environmental impact. In this study, the unsaturated polyester resin (rPET-UPR) is extracted from waste PET through the chemical recycling route (glycolysis) for the fabrication of four-ply glass fiber composites laminate of stacking sequence [0/(± 45)2/0]T. fatigue tests were performed at the stress ratio of 0.1, where the stress level varied from 40–80% of the ultimate tensile strength (UTS). The results of fatigue tests showed that the fatigue life of composites based on rPET-UPR was lower as compared to virgin polyester matrix composite probably due to weak interfacial properties and higher degradation of rPET-UPR matrix. Moreover rPET-UPR glass fiber composite had comparable fatigue performance. With increasing the fatigue loading cycle nonuniform and rapid damage growth were observed at high-stress levels however more uniform damage zone was observed at the low-stress level. From the fatigue fracture surface the fiber pullout, fiber pullout and fiber breakage, and fiber breakage failure mode was observed at 80%, 60%, and 45% stress level respectively while fiber pullout from intermediate ply had been observed might be due to weak interface and greater load transfer to intermediate ply after the failure of outer ply (UD). FE-SEM results revealed that excessive matrix damage was observed at low-stress level. The magnitude of stiffness degradation increased with decreasing the stress level might be due to excessive matrix damage.