Surface modification of aramid fiber by crystalline polyarylene ether nitrile sizing for improving interfacial adhesion with polyarylene ether nitrile.

The interfacial compatibility plays an important role in the performance of fiber-reinforced composite laminates. Aramid fiber is an important class of high performances fibers. However, the inertia of fiber surface is not conducive to the improvement of composite properties. In this work, polyarylene ether nitrile terminated with phthalonitrile (PEN-t-Ph) was supplied to modify the aramid fiber (m-AF). By heat treatment and riveting PEN-t-Ph to the fiber surface, a rough fiber surface can be obtained, and then the composite material with improved performance can be obtained through the entangling compatibility. Through SEM images, it could be seen that the fiber surface had the best rivet surface morphology when the fiber surface coated with 5 wt% PEN-t-Ph (m(5 wt%)-AF). At the same time, the interfacial adhesion between m(5 wt%)-AF and the resin matrix showed the best peel strength of 1.594 kN/m. Based on these results, modified fiber resin composite laminates (m(5 wt%)-AF/PEN-t-Ph) were fabricated. The results indicated that the laminates had good interfacial compatibility and the interlaminar shear strength (ILSS) of modified aramid fiber laminates was 112.58 MPa, which is increased by 21.4% than that of original fiber composite laminates. In addition, the flexural strength of m-AF/PEN-t-Ph laminates was 324 MPa, increased by 10% compared to AF/PEN-t-Ph. The results of DMA showed that the energy storage modulus of the m-AF/PEN-t-Ph laminate was greatly improved compared with that of AF/PEN-t-Ph laminate, which was increased by 60% under the initial condition of 100 °C. To sum up, through surface treatment, the mechanical properties of fiber-reinforced composite laminates had been greatly improved, making them have great application prospects in bulletproof and other fields. [ABSTRACT FROM AUTHOR]