Heat transfer analysis of natural fiber composites reinforced with waste glass dust: a numerical and experimental study

Rising demand for cost effective and light weight thermal insulation, necessitates to use industrial and bio-wastes in polymers to develop such materials. The estimation of their thermal properties are also equally pertinent. In view of this, the present work reports on the utilization of waste glass dust (WGD) as functional fillers in polymer composites reinforced with two different natural fibers like hemp and flax to develope a new class of thermal insulation. A unique one dimensional heat conduction model is developed to numerically estimate the k_eff of such composites using a finite element method based tool with suitable boundary conditions. Sets of hemp-epoxy and flax-epoxy composites of different filler concentrations (0 %–20 % by weight) are then fabricated using hand lay-up route. Thermal properties such as conductivity, coefficient of thermal expansion (CTE) and glass transition temperature (T_g) of the fabricated composites are measured. The numerical model and experimental results in regard to the conductivity are found to be in good agreement. It is also found that the k_eff of epoxy can be reduced up to 0.144 W/m.K, about 25 % by the reinforcement of natural fibers and waste glass dust. Similarly, a maximum reduction of about 34 % in the value of CTE (27.238 × 10⁻⁶/°C) is achieved. T_g is found to improve from 97 °C (epoxy) to 125.43 °C and 127.03 °C for hemp-epoxy and flax-epoxy composites respectively with the addition of the glass dust particles. Armed with reduced conductivity and favourable CTE and T_g, these composites can potentially be used in thermal insulation applications.