Thermal, acoustic, and dielectric behavior of epoxy-based hybrid composites using short hair fiber

Abstract

This study aims at investigating the thermal, acoustic, and dielectric behavior of a class of epoxy-based hybrid composite incorporated with, short human hair fibers (SHF), and solid glass microspheres (SGM). Epoxy composites filled with 10 wt% of SGM are prepared by solution casting method with different loadings (0, 5, 10, 15, 20 wt%) of SHF. Thermal properties of these composites such as thermal conductivity (K), coefficient of thermal expansion (CTE), and glass transition temperature (Tg) are evaluated by conducting tests as per appropriate ASTM standards. An impedance tube tester and a HIOKI-3532-50 Hi Tester Elsier Analyzer are used for measuring the sound absorption coefficient and dielectric constant of the composite samples, respectively. A theoretical model has been developed to predict the effective thermal conductivity of the hybrid composite considering minimal thermal contact resistance. Based on this model, a mathematical correlation between the effective thermal conductivity of the composite and the filler content is proposed. The results obtained from this correlation are found to be in good agreement with the experimental data. It is observed that with the increase in fiber content the thermal and acoustic insulation behavior of the hybrid composite has been significantly improved. The dielectric characteristics of the composites are also found to be substantially affected by the fiber content and operating frequency.