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Human hair is a biofiber having an exceptional chemical composition, higher strength in tension, and slow decomposition rate. In the present work, composites are fabricated by simple hand layup technique with epoxy matrix and different proportions of hair fiber (0, 5, 10, 15, and 20 wt%). Physical, mechanical, microstructural, and thermal characterization of the composite samples has been done by following the proper ASTM standards. A theoretical model has been developed to predict the effective thermal conductivity of the composite. Based on this model, a mathematical correlation between the effective thermal conductivity of the composite and the fiber content is developed. The results obtained from this correlation are in good agreement with the experimental data. This study explores the possibility of fabricating a class of epoxy composites with higher mechanical strength, superior insulation capability, improved glass transition temperature, and a low thermal expansion coefficient.

Polymer composites with low dielectric constant and high thermal conductivity are gaining considerable attention due to their rising demand in various microelectronic applications such as printed circuit boards, connectors, encapsulations, and electrical contacts. In the present investigation, thermal and dielectric properties of a new class of epoxy-based hybridized composites with improved thermal conductivity (k), high glass transition temperature (T g ), low coefficient of thermal expansion (CTE), controlled dielectric constant (D k ), and low dielectric loss (D L ) have been reported. Epoxy-based composites are fabricated by solution casting method with various wt% (0, 5, 10, 15, and 20 wt%) of short hair fiber and with a fixed proportion of micro-sized boron nitride (BN) (10 wt%) particles. Effects of fiber content on different thermal properties of the composites such as effective thermal conductivity (k), CTE, and T g are

This article reports on the fabrication and subsequently on the thermal properties of a biomaterial filled polymer composite consisting of polyester and walnut shell powder (WSP) in different proportions. The focus has been given to the evaluation of effective properties of the composites like thermal conductivity, glass transition temperature, and coefficient of thermal expansion. The experimental findings obtained for thermal conductivity are supported by the mathematical and numerical analysis made under suitable assumptions. A mathematical correlation is proposed to predict the effective thermal conductivity (Keff) of such particulate filled polymer composites. For the numerical study, a commercially available finite‐element package ANSYS19.2R2 is used to calculate the thermal conductivity of the composites. One dimensional heat conduction analysis is performed across composites with the periodic and randomly oriented arrangement of spherical fillers in different concentrations. Thermal conductivities of the composites are measured with Unitherm Model 2022 tester to validate the results. These values are then compared with effective thermal conductivities obtained from the proposed mathematical correlation and are found to be in close agreement with one another. It is concluded from this study that the addition of WSP improves the thermal insulation capability of neat polyester to a reasonable extent.

This work reports on the mechanical and wear performance of epoxy composite reinforced with short betel nut fiber (SBF). Composite samples with different weight percentages (0, 2, 3, 4, 6, and 8 wt%) of fiber content are fabricated through hand lay-up route. Mechanical properties such as tensile and flexural strengths are evaluated by conducting tests as per appropriate ASTM standards. Sliding wear tests are performed on a pin-on-disc test apparatus as per ASTM G99 standard. A non-linear regression model is developed in accordance with face-centered central composite design (FCCCD) of Response Surface Methodology (RSM). An artificial neural network (ANN) approach is applied to predict the wear rate of the composite and compared with the RSM predicted results. It is found that with the incorporation of short betel nut fiber both tensile and flexural strength of the composite shows an increasing trend. It is also observed that reinforcement of short betel nut fiber enhances the wear performance of epoxy. Surface morphologies of the worn samples have been studied to analyze the wear mechanism of the composite samples.

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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