Enhancing thermo-mechanical performance of epoxy composites using alkali-treated almond shells for automotive applications

Automotive companies are now concentrating on finding new materials that are light, eco-friendly and affordable to help improve fuel economy and lower the industry’s impact on the environment. The thermo-mechanical properties of epoxy-based composites with almond shells are studied at five different weight fractions (10%, 20%, 30%, 40% and 50%). Alkali (NaOH) was used to modify the surface characteristics of almond shells, and the results were examined in terms of their tensile strength, chemical interactions, and thermal stability. Tensile testing, Fourier Transform Infrared Spectrometry (FTIR), and Thermo-Mechanical Analysis (TMA) were used to study the materials in detail. The results demonstrate the significant benefits of the alkali treatment. Tensile strength was markedly improved, with treated composites showing enhancements of up to 38.5% at a 10 wt% fraction (150 µm particles) compared to their untreated; the optimal formulation (20 wt%, 150 µm) achieved a peak tensile strength of 27.50 MPa. Thermo-Mechanical Analysis (TMA) revealed a dramatic increase in stiffness, with the peak modulus of treated samples increasing by over 239% in certain configurations. Fourier Transform Infrared Spectrometry (FTIR) confirmed the chemical basis for these improvements, showing the successful removal of amorphous hemicellulose and lignin from the filler surface. These findings highlight that composites reinforced with NaOH-treated almond shells are a high-performance, lightweight, and eco-friendly material suitable for various automotive applications. Field Emission Scanning Electron Microscopy revealed that NaOH surface treatment significantly enhanced interfacial bonding and particle dispersion.