Effects of in-situ cryogenic testing temperature and ex-situ cryogenic aging on the mechanical performance of glass fiber reinforced polymer composites with waste short carbon fibers as secondary reinforcements

Composite components' fabrication generates vast amounts of fiber wastes. This research suggests using short carbon fibers (SCFs) as secondary reinforcement in glass fiber reinforced polymer (GFRP) composite for cryogenic application. The SCFs (0.1, 0.3, and 0.5 wt%) were embedded in GFRP composites. Flexural test was performed to assess the integrity and durability of composites at in-situ cryogenic temperature (CT), and after ex-situ cryo-aging in liquid nitrogen for various time intervals (0.25, 0.5, 1, 2, 4, 8, and 16 h). The composite with 0.1 wt% of SCFs showed the highest enhancement in flexural performance in all testing conditions, similar to 16% at Room Temperature (RT), similar to 12% at Cryogenic Temperature (CT, and between 13% and 39% after cryo-aging. Composites with SCFs retained their strength at CT and after cryo-aging, suggesting that the waste fibers could be economically reused and preferred over other expensive nanofillers as secondary reinforcements in GFRP composites for cryogenic applications.