Testing and evaluation on the thermal and mechanical properties of carbon nano fiber reinforced SC-15 epoxy

Abstract

In the present investigation, we have developed a novel technique to fabricate nanocomposite materials containing SC-15 epoxy resin and carbon nano fiber (CNF). A high-intensity ultrasonic liquid processor was used to obtain a homogeneous molecular mixture of epoxy resin and carbon nano fiber. The carbon nano fibers were infused into the part A of SC-15 (diglycidylether of Bisphenol A) through sonic cavitations and then mixed with part B of SC-15 (cycloaliphatic amine hardener) using a high-speed mechanical agitator. The trapped air and reaction volatiles were removed from the mixture using high vacuum. DMA, TGA and 3-point bending tests were performed on unfilled, 1 wt.%, 2 wt.% and 4 wt.% CNF filled SC-15 epoxy to identify the loading effect on thermal and mechanical properties of the composites. The flexural results indicate that both modulus and strength increased with increasing loading percentage of CNF. DMA studies also revealed that filling the carbon nano fiber into epoxy can improve storage modulus and Tg compared to neat system. However, TGA results show that thermal stability of composite is insensitive to the fiber content. Based on the experimental results, a nonlinear damage model was established to describe the stress–strain relationship of the epoxy and its nanocomposite. The parameters in this model are tensile modulus E, Weibull scale parameter σ 0 and Weibull shape parameter β. Simulated results show that both Weibull shape parameter, β, and Weibull scale parameter, σ 0, increased with increasing carbon nano fibers content.