Interlaminar Fracture Toughness of Carbon Fiber Reinforced Polymers Enhanced With Polyethersulfone/Graphene Oxide Films Under Low‐Temperature/Salt‐Spray Environments

ABSTRACT To address the degradation of interlaminar properties in carbon fiber reinforced polymer (CFRP) composites under harsh environmental conditions, this work prepared high‐performance unidirectional CFRP laminates by interlaying polyethersulfone (PES)/graphene oxide (GO) films. This preparation method enhances the interlaminar fracture toughness of the composite in low‐temperature/salt‐spray environments. Through double cantilever beam (DCB) and end‐notched flexural (ENF) testing, the optimization effect of the novel composite film on interlaminar fracture toughness under harsh conditions was analyzed. Results indicate that under low‐temperature/salt‐spray conditions, the PES/GO film significantly enhances the mode II interlaminar fracture toughness of CFRP laminates through mechanisms such as resin‐fiber interface reinforcement, moisture barrier, and self‐sealing effects, achieving an improvement of up to 64.44% and demonstrating outstanding toughening capability. Simultaneously, the PES/GO film also played a stable role in maintaining the mode I interlaminar fracture toughness of the laminate. Furthermore, analysis of specimen moisture absorption rates and micro‐interlaminar images revealed damage patterns in the interlaminar regions caused by environmental factors. This work elucidated the matrix‐interlaminar interface behavior and failure mechanisms of interlaminar reinforcements, providing theoretical foundations and technical insights for future development of novel environmentally adaptive composite materials.