Sustainable utilization of distiller’s dried grains with solubles: Ammonium polyphosphate bonded particleboard with enhanced strength and flame retardancy

The Chinese Baijiu industry produces over one billion tons of distiller’s dried grains with solubles (DDGS) annually, posing a significant environmental challenge. Traditional methods of utilization are hindered by numerous limitations, including insufficient treatment, low-value processing, and high energy consumption. In this study, ammonium polyphosphate (APP), an inorganic adhesive, was employed to bond DDGS for its materialization. APP self-condensed to intensify its van der Waals force attraction to DDGS—eschewing any chemical reaction with DDGS, resulting in the formation of DB-APP4, which exhibits optimal mechanical properties unaffected by variations in DDGS reactivity. With a modulus of rupture of 12.48 MPa, a modulus of elasticity of 2221.65 MPa, an internal bond strength of 0.56 MPa, and a thickness swelling rate of 5.53 %, DB-APP4 satisfies the fundamental performance criteria for particleboard as outlined in ISO 16978:2003. Furthermore, owing to APP’s ability to catalyze the formation of a protective carbon layer on the material surface while preserving the high porosity characteristic of biomass, the flame retardancy of DB-APP4 has reached Class B 1 . This study not only addresses the challenge of effectively repurposing DDGS but also provides a pioneering and practical approach for the industrial application of DDGS-based particleboards. • The distiller’s dried grains with solubles (DDGS) from brewing can be repurposed. • Transformed into particleboard, the solid waste DDGS has been materialization. • Ammonium polyphosphate (APP) can improve the strength and flame retardancy of particleboard. • APP achieved the enhancement of particleboard strength through self-condensation. • APP boosted flame retardancy by catalytic carbonization and biomass porosity preservation.