Environment Friendly Binderless Cellulose Based Thermal Insulation Building Material Made of Forestry Waste

This research investigates environmentally friendly, binderless thermal insulation fibreboards utilizing three types of raw materials. The primary objective was to evaluate the usability of forest residues. For comparison, the same production process was applied to sawdust residues from hybrid poplar (Populus euramericana) and Scots pine (Pinus sylvestris). Five processing variations were applied to the undergrowth biomass, including treatment with a Hollander beater for 20, 40, and 60 minutes to optimize the final product properties. The samples were characterized based on density, equilibrium moisture content, morphology, porosity, thermal stability, and thermal conductivity. Among the tested approaches, the samples produced from forest residue with 40 minutes of Hollander beater treatment achieved the most favorable balance of properties. The best thermal conductivity was 0.0691 W/m·K, moderate density, and improved porosity (53.38%), closely matching the performance of the poplar-based panels. Conversely, pre-soaking biomass in water for three days increased density and moisture content, negatively impacting thermal performance. Thermogravimetric analysis confirmed that the thermal stability of the forest residue panels was comparable to those made from traditional pine and poplar sawdust. FTIR analysis indicated that the self-bonding properties were primarily facilitated by the inherent lignin and hemicellulose content of the raw materials.