New Generation Fibre Reinforced Polymer Composites for Low and Cryogenic Temperature Applications

Abstract

In the present investigation, alteration in flexural performance of glass-epoxy (GE) composite and CNT (0.3%)-GE for low temperature and glass-epoxy (GE) composite and CNT (0.1%, 0.3% and 0.5%)-GE composites due to liquid nitrogen conditioning is studied for various time lengths. The epoxy resin is first modified by 0.1% ,0.3% and 0.5% MWCNT, which is then used along with E-glass fibres to fabricate laminate.Flexural strength and modulus were evaluted by 3-point bend test. For low temperature conditioning, addition of 0.3 wt. % MWCNT into GE composite significantly lowered the Tg by 12 °C due to hindrance in crosslink formations. The reinforcement efficiency (relative change in modulus) due to CNT incorporation in GE composite is as high as 30%, when the testing temperature was -80 °C. For cryogenic conditioning, out of these four compositions the maximum strength is as the fabricated conditioned for GE composite with 0.1% CNT, which is 32.7% higher than GE composite. Decrease in strength and modulus observed for short time span of liquid nitrogen conditioning i.e. 0.25hr. Long cryogenic conditions resulted in increment in strength. To understand the failure mechanisms, post failure fractography analysis was carried out using scanning electron microscope. The design parameters are then calculated using Weibull distribution model.