Thermomechanical properties and high-temperature stability of epoxy resin modified with boron-based inorganic phases

Abstract This study concerns the manufacturing and complex characterization of the Epidian 5 epoxy resin with the addition of low-density ceramic phases, containing boron in their crystallographic structure. The composite was designed to contain fine powders of boron carbide and hexagonal boron nitride in quantities up to 20 vol% as reference compositions, compared with a material prepared with up to 20 vol% of a 50/50 vol% mixture of boron carbide and boron nitride. Low additive contents caused a slight decrease in the glass transition temperature, whereas significant changes in storage modulus were observed at inorganic phase concentrations of 10 vol% and above. The incorporation of boron-based phases generally resulted in nearly linear changes in thermal transport properties and hardness. Hexagonal boron nitride exerted the strongest effect on thermal diffusivity and thermal conductivity, while boron carbide produced the most pronounced increase in hardness. Composites containing the BCBN mixture exhibited intermediate thermal and mechanical properties, particularly at higher inorganic phase concentrations. The paper explains material’s behavior through thermal analysis, dynamic mechanical analysis, dilatometry and heat transfer, and the correlations among them. Due to the wide range of potential applications, including military, electrical and coating technologies, the paper characterizes and analyzes the influence of boron-based phases and their mixtures of friction coefficient and material wear.