Mechanical, wear, flammability, and thermal conductivity behaviour of epoxy composites reinforced with bottle gourd stem cellulose and chopped grape stem fibers

Abstract

To develop epoxy-based composites suitable for various engineering applications requiring high mechanical strength, superior wear resistance, good fire resistance, and enhanced thermal conductivity, silane-treated chopped grape stem fibers and bottle gourd stem-derived cellulose were incorporated into an epoxy resin matrix using the manual layup method. In accordance with ASTM standards, the influence of cellulose concentration and surface modification on the composite’s mechanical, wear, thermal conductivity, and flammability properties was systematically investigated.The results revealed that increasing the cellulose concentration generally improved the overall performance of the composites. The composite containing 9 vol% cellulose and 30 vol% chopped stem fiber (BFF5) demonstrated the best combination of functional properties. It exhibited superior wear resistance with the lowest specific wear rate of 0.39 mm³/Nm and a coefficient of friction (COF) of 0.56. Additionally, it achieved the highest thermal conductivity of 0.475 W/mK, the longest burning duration with a flame spread rate of 8.33 mm/min, and the highest hardness value of 99 Shore D.In contrast, the composite with 5 vol% cellulose (BFF3) showed the highest mechanical properties, recording a tensile strength of 137.6 MPa, an impact energy of 3.82 J, and a flexural strength of 157.6 MPa. The failure mechanisms of the tested specimens were further examined using scanning electron microscopy (SEM), providing detailed insights into fiber-matrix interactions and fracture behavior.