Preparation of Polyimide Nanofiber Membranes and Interlaminar Toughness Investigation of Their Toughened Composites

Abstract

Interlaminar delamination and brittle fracture of matrix have been a dilemma that fiber-reinforced composites have been faced with. Herein, the polyimide (PI) nanofiber-toughened glass fiber fiber-reinforced epoxy composites were prepared by electrospinning method and subsequent vacuum assistant resin transfer molding. The effect of spinning parameters including PI concentration, applied voltage, collector distance, jet speed and ambient humidity on the resultant fiber diameter and its distribution was systematically evaluated. The surface properties of obtained PI nanofibers were characterized by FT-IR, TG-DSC and water contact angle. The effect of PI concentration on tensile strength of PI membranes was also studied. The mode I (G[Formula: see text] and mode II (G[Formula: see text] interlaminar fracture toughness were measured. The results indicated that GIc and GIIc increased by 127.69% and 85.33%. The improvement of interlaminar fracture toughness may be attributed to the bridging effect of PI nanofibers.