Flexural and low velocity impact characterization of thermoplastic composites based on PEN and high performance woven fabrics

Poly(Ethylene 2,6-Naphthalate)PEN has been used as matrix for laminates with the aim to develop woven fiber reinforced composites with a service temperature as high as 100 degrees C. Three different classes of fibers have been considered as reinforcement in woven fabric form: carbon, polymers (Twaron and Vectran) and mineral (basalt). Composites were manufactured by using the film stacking technique, alternating layers of balanced plain weave fabrics (0/90) and films of amorphous PEN. The manufacturing process was optimized to obtain a good impregnation of fibers and very low void content. Static flexural tests, dynamic mechanical analysis and low velocity impacts were used to characterize the mechanical behavior of the composites. The flexural modulus and strength of laminates resulted to be very high, in particular for the PEN/Carbon and PEN/Basalt systems. The storage modulus from the dynamic mechanical analysis indicated that 100 degrees C is a suitable service temperature for all configurations. The impact resistance of the composites showed a different trend with respect to static tests, since PEN/Basalt and PEN/Aramid exhibited the best performances. These results prove that PEN is a viable option for the production of structural composites as replacement of thermosetting matrices due to its high performance/cost ratio, in particular when combined with basalt fibers. POLYM. COMPOS., 39:2942-2951, 2018. (c) 2017 Society of Plastics Engineers