The effect of cryogenic thermal cycling on impact performance of graphene-enhanced recyclable liquid thermoplastic/carbon fiber composites for hydrogen storage applications

Abstract

This study presents a novel investigation into the impact energy absorption characteristics of graphene nanoplatelet (GNP)-enhanced carbon fiber-reinforced liquid thermoplastic composites under various cryo-thermal cycling conditions. For the first time, we evaluate the performance of carbon fiber reinforced composites composed of liquid thermoplastic as a matrix and graphene nano platelets (GNPs) as additives for hydrogen storage applications. Laminates with various GNP concentrations (0, 0.25, 0.5, 1, and 1.5 wt.%) in liquid thermoplastic resin (Elium) were prepared. The laminates were subjected to cryo-thermal cycling (0, 1, 10, and 25 cycles) before testing at low-velocity impact (5, 10 and 20 J). The results showed that GNP-reinforced composites exhibited a superior retention of impact resistance under cryo-thermal cycling, with the 0.5 wt.% GNP composite demonstrating the best overall impact performance. Specifically, this composite achieved an 8 % increase in peak contact force and a 10 % increase in absorbed energy over the neat composite, due to its ability to alleviate thermal stresses. However, increasing the GNP content beyond this threshold resulted in particle aggregation, which reduced the mechanical properties. After extended cryo-cycling, all composites exhibited a decline in performance, with the neat samples experiencing the greatest reductions: 18 % in peak contact force and 14 % in absorbed energy. In contrast, the 1.5 wt.% GNP samples displayed better resilience, with reductions of only 6.5 % in the peak contact force and 4 % in absorbed energy.