The Effect of Symmetrical Aramid Membranes on the Performance of Aramid Fiber Composite Materials

ABSTRACT

Symmetrically porous para‐aramid (PPTA) membranes with tunable porosity (referred to as hPPTA) were used to improve the interfacial adhesion and interlaminar toughness for the aramid fiber to epoxy, which were fabricated using microporous filter membranes as templates and polyvinylpyrrolidone (PVP) as the porogen. These hPPTA membranes were integrated as interlaminar reinforcing phases into aramid fiber/epoxy (AF/EP) composites via a vacuum‐assisted resin infusion molding process. The effects of the PVP content on the porous structure and the mechanical properties of the composites were studied. When the PVP content is 5 wt%, the results of the scanning electron microscopy (SEM) and contact angle analysis revealed that the porous architecture of the hPPTA promoted thorough epoxy resin infiltration, thereby enhancing the interfacial bonding between EP and the PPTA. Dynamic contact angle measurements further confirmed that EP uniformly penetrated the membranes and wetted the fibers, demonstrating the capability of the hPPTA to serve as an effective stress transition layer. At a PVP content of 5 wt%, the AF‐hPPTA‐EP composites exhibited marked increases in tensile, flexural, and interlaminar shear strengths (ILSS) of 14.9%, 27.9%, and 29.6%, respectively, compared to the unmodified AF/EP composites. Furthermore, the hPPTA‐reinforced composites also displayed a 31.8% higher residual impact bearing load and a 45.5% higher impact energy absorption than the AF/EP composites. These findings demonstrate that the porous PPTA membranes significantly enhance interfacial adhesion and interlaminar toughness in advanced composites.