Mechanical properties of electrospun CNF/PVA nanofiber mats as reinforcement in polymer matrix composites

Carbon nanofiber (CNF) reinforcement in the resin matrix composites is one of the effective methods which improve the overall performance of the composites. In this work, we have investigated the influence of electrospinning to obtain nanofiber composites of carbon nanofiber (CNF)/polyvinyl alcohol (PVA) by varying the percentages of CNF (i.e., 1, 1.5 and 3 wt %). CNF incorporation has been confirmed by X-Ray diffraction and SEM analysis of nanofibers revealed that the fiber diameter increased with respect to CNF percentage. Then, we fabricated flexural coupons utilizing CNF/PVA nanofiber mats as laminates and epoxy resin (ER) as matrix. A total of fifteen coupons, five for each CNF weight percentages, were finally obtained. The fabricated coupons had smooth surfaces. Ultrasonic testing (UT) provided information about the defects present in the coupons. Three point flexural tests performed through a 10 ton universal testing machine (UTM) following the ASTM standard showed significant improvement in the flexural strength of the CNF loaded polymer composites. The maximum flexural strength of 137.28 MPa was obtained with the 3 wt% CNF loaded coupons (i.e., C3P-4), compared to the pure epoxy coupons (65.31 MPa from NC-2). The flexural strength was compared with directmixed CNF/ER composite coupons (dM-CPs) and found to increase as much as 46%. The uniform dispersion of CNF/PVA with tunable nanofibers, their higher surface area and load bearing characteristics could be attributed for this enhanced strength and these composites may open up numerous possibilities for industries like defense and automobile.