Production and Characterization of Corncob-Borax Particulate Reinforced Polyester Composites for Flame Retardant Applications

Abstract This study explores the influence of corncob and borax reinforcements on the mechanical and flame-retardant properties of polyester composites. Composites were produced using the hand lay-up technique with varying weight percentages of treated-corncob (3, 9, 15 wt%) and borax (12, 15, 18 wt%). Mechanical properties such as tensile and flexural properties, hardness, and impact resistance were evaluated, alongside flame retardancy through burning rate tests. Morphological and elemental analyses were conducted using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX), while Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) provided insights into the chemical structure and crystalline phases. The XRD analysis indicated an increase in the crystallinity index of treated corncob, suggesting enhanced order within the cellulose structure, which correlates with improved mechanical properties. FTIR results confirmed the presence of functional groups indicative of cellulose, suggesting effective interaction between the fillers and the polyester matrix. The findings revealed that adding borax and corncob significantly enhanced hardness, flexural, and tensile modulus, with the composite containing 18 wt% borax and 15 wt% corncob exhibiting optimal performance. However, tensile strength and impact resistance decreased slightly compared to pure polyester due to stress concentrations. In flame retardancy tests, higher borax content notably reduced burning rates, with the composite containing 18 wt% borax and 15 wt% corncob demonstrating superior flame resistance. In conclusion, the hybrid reinforcement of borax and corncob in polyester offers a sustainable solution, enhancing mechanical properties and flame resistance, making these composites suitable for applications requiring both durability and fire safety.