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 (T g) 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. Keywords Polymer composites • Hair fibers • Thermal characterization • Acoustic insulation List of symbols Q Heat flow through the cross-sectional area of an element of composite Q p 1 , Q p 2 Heat flow through the cross-sectional area of polymer matrix in part C and part D of the element Q f 1 , Q f 2 Heat flow through the cross-sectional area of fiber and particulate of part C and part D of the element dT Temperature difference between two side of the element k eff Effective thermal conductivity of the composite material k p , k f 1 , k f 2 Thermal conductivity of polymer matrix, fiber, and particulate R eq Total equivalent heat resistance of the element R eq 1 , R eq 2

Acoustic performance of natural fiber reinforced polymer composites: Influencing factors, future scope, challenges, and applications

“…[98] With the addition of a solid glass microsphere as the hybrid filler, a considerable increase in the thermal and acoustic insulation characteristics of the composite was found. [107,109] Changes in the reinforcing architecture of the fibers lead to changes in their acoustic properties. [14,17,104,105] The coir fiber had a good sound absorption coefficient and transmission loss index value, according to the acoustic property results.…”

Characterization and Static Responses of Partially Biodegradable Hybrid Composites: Experimental and Numerical Analysis

“…Conversely, animal fibers (wool, silk, hair) are composed of complex proteins (keratin) that have a unique combination of amino acids [20]. In this context, the Human hair fiber (HHF) is a promising natural material for composites due to its unique properties such as high aspect ratio, non-toxic, non-allergenic, and biocompatible along with the requisite properties like high strength, stiffness, toughness (due to the presence of disulphide bonds), dielectric and good thermal as well as acoustic insulation properties [21], [22]. The hybridization of alkali treated plat based and animal based natural fibers also found to improve the physical, mechanical, thermal as well as acoustic insulation properties [23] along with the machinability characteristics [24].…”