Enhancing the Bending and Interlaminar Shear Performance of Glass/Epoxy Composites at in-situ Elevated and Sub-zero Temperatures by incorporating Recycled Short Glass Fibers

Abstract

Sustainable recycling and reuse of recycled glass fibers are essential for minimizing environmental impact and promoting resource efficiency. This study aims to recycle and reuse the recycled short glass fibers (RSGFs) by chopping and incorporating them in virgin glass fiber-reinforced epoxy composites (VGFECs) at varying concentrations (i.e., 0.1%, 0.3%, 0.5%, and 0.7%) with respect to the weight of epoxy for enhancing the mechanical performance. The flexural performance of RSGFs incorporated VGFECs at 70℃ and at -20℃ after conditioning at -50℃ was evaluated. The flexural strength and modulus of 0.3RSGF-VGFEC (VGFEC containing RSGFs weighing 0.3 wt% of Epoxy) at 70℃ are ~13% and ~5% higher than those of VGFEC. On the other hand, due to differences in the coefficients of thermal expansion, the flexural strength of VGFEC and 0.3RSGF-VGFEC dropped by ~19% and ~21% as the testing temperature increased from room temperature (RT) to 70℃. However, the flexural strength of VGFEC and 0.3RSGF-VGFEC increased by ~3% and ~7% after conditioning at -50℃ for 6hours and reducing the testing temperature from RT to -20℃. At -20℃, the flexural strength and modulus of 0.3RSGF-VGFE are ~20% and ~21% higher than VGFECs. The short beam shear tests revealed that the incorporation of RSGFs in VGFECs has also improved the interlaminar shear strength of the VGFECs. The fractography of RSGF-VGFECs revealed crack bridging by RSGFs. This study provides critical insights into the recycling and reuse of recovered glass fibers in polymeric composites for high-performance applications in aerospace, railways, automotive, and cryogenic environments.