Sustainable wood composite production using cotton waste and exopolysaccharides as green binders

Burning agricultural waste is a common practice among farmers in many countries, leading to global warming and climate change. Upcycling abundant agricultural waste will prevent incineration-generated hazards and provide sustainable and eco-friendly wood. An alternative wood composite was prepared using Aspergillus niger mycelium and exopolysaccharides (EPS) as a green binder. Autoclaving and gamma irradiation were both tested as wood pre-treatment to enhance binding. The mixture was incubated at 30 °C for 1 week. The results showed that wet pre-treatment using autoclaving resulted in improved wood binding compared to dry gamma irradiation treatment. The results show that the composite with the lowest water absorption was autoclaved before inoculation with 25 % EPS-induced Aspergillus niger, its tensile strength was 2.01 MPa and Modulus of elasticity of 1240.42 MPa and water resistance duration of 72 h. The biodegradation rate was 21.5 % for linseed oil-coated composite compared to 15.63 % for non-coated wood after 6 weeks. The samples demonstrated thermal conductivity as low as 0.06025 W/mK and linear Ohmic behavior within the investigated voltage range, rendering it a competitive insulating material. In conclusion, autoclaving and inoculum size play a key role in binding cotton wood waste. The key results render the optimized composite suitable for industrial applications due to its affordability, green manufacturing process, and potential for large-scale production.