Effect of Brown-Rotted Spruce as Lignin-Enriched Filler on the Properties of Reinforced Polyurethane Foam

The study investigated the effect of lignocellulosic biomass filler decayed by brown-rot fungi on the preparation and properties of polyurethane (PU) foam. The properties of brown-rotted spruce were characterized by microstructure, chemical composition, and hydroxyl value to examine the possibility of preparing polyurethane foam using brown-rotted spruce as filler. Brown-rotted spruce was a homogeneous material, mainly composed of lignin (80.36%) with a high content (284.5 mg KOH/g) of hydroxyl groups in structure that could participate in a chain reaction with isocyanate groups on the foaming process. In the study, PU foams were prepared successfully with the addition of brown-rotted spruce as filler in different concentrations (1-10 wt%). The results showed that the addition of brown-rotted spruce improved the physical properties (low density, low thermal conductivity, high water absorption) of PU foam. These properties showed a significant dependence on filler amount. The density decreased from 89.64 kg m(-3) to 60.22 kg m(-3) as the filler amount increased. Scanning electron microscope showed the cellular structure of PU foam was affected by the filler amount. PU foam with low addition amount (5 wt%) had homogeneous shapes and smaller cell shapes, resulting in the highest compressive strength (0.42 Mpa). Utilizing brown-rotted wood as a lignin-enriched filler is a simple and feasible way to improve the properties of PU foam. [GRAPHICS] .

Automated summary

The study investigated the effect of using decayed lignocellulosic biomass filler on the preparation and properties of polyurethane foam. The results showed that the addition of decayed lignocellulosic biomass improved the physical properties of the foam, including low density, low thermal conductivity, and high water absorption. These properties were found to be dependent on the amount of filler added.