Investigation of mechanical properties of pan nanofiber/pe reinforced self-healing GFRP composites

To enhance the durability and reliability of glass fiber-reinforced epoxy matrix polymer composites (GFRP), four types of specimens were fabricated using the vacuum bagging method. These specimens consist of: (i) the unmodified neat structure, (ii) the epoxy matrix modified with 15 wt.% high-density polyethylene (PE) powder, (iii) the structure incorporating a polyacrylonitrile (PAN)-based electrospun nanofiber mat as an interlayer, and (iv) a hybrid structure combining both modifications. The specimens were subjected to low-velocity impact tests, and half of them were re-tested after being heat-treated at 150 °C for 30 min. The incorporation of PE resulted in a decrease in peak load compared to the reference specimens; however, this loss was largely recovered after heat treatment due to the filling of microcracks. The presence of PAN nanofiber interlayers limited the initial load drop, while the hybrid structure combined the advantages of both modifications; exhibiting the highest initial impact strength, maintaining its capacity after repeated impact, and showing the lowest permanent indentation depth. An additional increase of approximately 10% was observed after heat treatment. Scanning electron microscopy (SEM) analyses revealed that the melted PE migrated along the nanofiber mat, repairing the delamination regions. This phenomenon demonstrated an effective and synergistic self-healing mechanism. The findings indicate that while the PAN nanofiber mats act as barriers to crack propagation, PE provides a thermally triggered healing function. The synergistic interaction of these two components presents a feasible approach for achieving enhanced impact resistance and recovery of mechanical integrity in lightweight GFRP composites.