Characterization of glass-fiber reinforced thermoplastic composite after ultrasonic reconsolidation

Value-retention of fiber-reinforced polymer composites is a necessary approach that must be addressed for the end-of-use (EoU) composites or scrapped composites produced during manufacturing. With the novel ultrasonic enhanced separation and reconsolidation approach, these EoU or scrap composites can be recovered, and their properties can be retained. In this work, a glassfiber (GF) reinforced composite embedded in a thermoplastic polypropylene (PP) matrix was investigated for the circularity option through the application of power ultrasonics. A statistical design-of-experiment approach was used to reconsolidate the GF-PP specimens. The specimens were reconsolidated with an oscillation amplitudes ranging from 28 to 40 µm, reconsolidation force of 300-500 N, and holding time ranging from 5  to 15 s. The reconsolidated GF-PP specimens were then mechanically tested for their performance by three-point bending and short-beam tests. The evaluated mechanical test results showed that 96% of the flexural property and 95% of the inter-laminar shear strength (ILSS) were retained compared to the original laminate condition. Cross-sectional microscopic investigation on the reconsolidated GF-PP specimens also supported the evaluated values from flexural and short-beam tests which could correlate with the experimental parameters directly.