Investigation of flame retardancy, microstructure and water absorption properties of wood fiber composite for military gears

Abstract

The need for flame retardant polymers in high performance applications has amplified the search for sustainable materials that should  address safety concerns. The research aims to investigate the flammability, microstructure and water absorption of wood fiber composites. Equal composition of PET and HDPE were used for this study with varying concentrations of wood fiber as follows 0%, 10%,  20%, 30%, 40% and 50%. Compression moulding and blending was carried out in fabricating the wood fiber composite. Characterization  was carried out on the composite using FTIR and SEM techniques. Other properties such as flammability and water absorption were  evaluated for the composite. The results of FTIR analysis revealed chemical modifications in treated fibers, which indicate the formation  of new alkynes (2102.6 cm⁻¹) and carbonyl groups (1900.9 cm⁻¹, 1729.5 cm⁻¹), along with shift in hydroxyl peaks (3518.8 cm⁻¹, 3377.3 cm⁻¹).  SEM micrographs showed uniform dispersion at lower filler ratios (20/80%) but agglomeration at higher levels (30/70%, 50/50%).  Flammability tests demonstrated enhanced flame retardancy (UL 94 VO rating) compared to the control. Water absorption increased with  higher fiber content (WFA: 1.61%, WFB: 3.45%, WFC: 4.83%, WFD: 9.65%, WFE: 10.85%). These results highlight the significance of filler concentration and fiber treatment in optimizing Wood Fiber Composites for applications in wearable materials and safety related  industries.