A comparative study on the effect of reinforcing boron nitride/alumina in epoxy-based hybrid composite with Millettia pinnata leaf powder and glass sheets: Experimental fabrication, mechanical and micro-structural characterization

Abstract

The present study focuses on the fabrication and characterization of an innovative epoxy-based hybrid composite, designed to enhance its mechanical properties by incorporating three distinct reinforcing agents that are Millettia pinnata leaf powder, alumina/boron nitride particles, and glass sheets. This hybrid composite aims to combine the individual strengths of alumina/boron nitride particles reinforcements, ultimately achieving a superior material with enhanced mechanical strength. The selection of these reinforcements was based on their unique properties, such as biodegradability and eco-friendliness of Millettia pinnata leaf powder, high strength-to-weight ratio of alumina/boron nitride, and excellent mechanical properties of glass sheets. The optimized weight fraction of each reinforcement was determined through a series of experimental trials to maximize the composite's performance. The characterized thermo-mechanical properties included tensile strength, flexural strength, impact strength, and hardness. Additionally, microstructural analysis was performed using the scanning electron microscopy to examine the interfacial bonding between the matrix and reinforcements, offering insights into the composite's overall integrity. The findings revealed that the incorporation of Millettia pinnata leaf powder, alumina/boron nitride, and glass sheets led to significant improvements in the mechanical properties of this hybrid composite. The composite exhibited enhanced tensile and flexural strength, resulting from the reinforcing effects of alumina and glass sheets. Comparatively, the mechanical properties of boron nitride composites tend to be higher than that of the alumina composites. Maximum tensile strength, flexural strength, impact strength and hardness for the boron nitride composites are 312.21 MPa, 19.53 MPa, 53.68 kJ/m2 and 103.25 HRL, respectively at composition of 6 grams of boron nitride and 6 grams of Millettia pinnata leaf powder; whereas, for the alumina composites these values are 211.84 MPa, 15.46 MPa, 44.12 kJ/m2 and 101.23 HRL at composition of 6 grams of alumina and 6 grams of Millettia pinnata leaf powder. The results reported in this study will be helpful in accelerating the industrial applications of epoxy-based hybrid composites.