Enhancing water resistance of medium density fibreboards via periodate oxidation of thermomechanical fibres

Medium density fibreboard (MDF) is an essential material in global manufacturing, valued for its versatility and cost-effectiveness. Enhancing its water resistance is critical for broadening its applications, especially in humid and outdoor environments. This study investigates the enhancement of MDF water resistance through the chemical modification of the constituent wood fibres (in this case, thermo-mechanical pulp or TMP) through periodate oxidation. The treatment with sodium metaperiodate results in the formation of dialdehyde fibres (DA-TMP) which are then spray-coated with a phenol-formaldehyde resin, following the industrial procedures, and converted into a MDF through proper hot pressing. Comprehensive evaluation of the physical, mechanical, and biological properties is conducted, along with the study of fire behaviour comparing boards made from both oxidized and non-oxidized fibres. The results reveal that periodate oxidation reduces water absorption by 54% and thickness swelling by 56%, indicating significant changes in the fibres’ chemistry and morphology. Despite a slight decrease in mechanical properties, the overall performance of DA-TMP based MDF confirms this as a promising method for achieving superior durability in moisture-prone environments, including outdoor constructions. Importantly, the biological resistance of the material remains unaffected by the oxidation of the fibres, ensuring continued protection against biological attack and long-term durability. Additionally, fire performance tests show that DA-TMP based MDF exhibit reduced peak heat release and smoke production, further enhancing their suitability for fire-sensitive applications. Consequently, this research contributes to expand the use and durability of wood-based materials across various industrial sectors, offering a sustainable and effective alternative to traditional moisture resistance treatments.