Influence of Soluble Electrospun Co‐Polyethersulfone Veils on Dynamic Mechanical and Morphological Properties of Epoxy Composites: Effect of Polymer Molar Mass

Abstract

Abstract Electrospun veils from copolyethersulfones (co PES ) with a number‐average molar mass (Mn) of 9000 g/mol (co PES 9k) and 20,000 g/mol (co PES 20k) were prepared as soluble interlaminar veils for carbon fiber/epoxy composites. Dry carbon fabrics were covered with electrospun veils and then infused with an unmodified epoxy resin to prepare reinforced laminates. Co PES powder was predissolved in the unmodified epoxy to obtain an epoxy/co PES blend used for preimpregnation of laminates which were compared to the laminates obtained with resin infusion. The thermoplastic content varied from 10wt% to 20wt% for co PES 9k and from 5wt% to 10wt% for co PES 20k. Unreinforced samples with no carbon fabrics were also studied. The co PES 9k veils showed full solubility and homogeneous morphology when added to the epoxy resin. Unreinforced samples, modified by co PES 9k veils, showed only minor morphological differences compared to epoxy/co PES blends obtained from co PES 9k powder predissolution. The glass transition temperatures for these samples displayed differences less than 10°C. Carbon‐reinforced samples obtained using the same route showed larger differences. The co PES 20k veils showed undissolved fibers and inhomogeneous morphologies when blended with an epoxy in the unreinforced samples.