Alternative Particleboards Based on Treated and Untreated Hay

Agricultural resources have a great potential to be a supplement or replacement for wood, especially in countries lacking wood resources, or during times of economic turmoil of wood markets, for manufacturing panel products. Previous research has focused on various sources including wheat straw, rice straw, rapeseed, or oil palm stems, but so far hay was not considered. Hay consists of cut and dried grasses, legumes, or other herbaceous plants. It has similar structure to wheat straw with a typical waxy surface layer and poor bondability. Soaking in NaOH was employed to improve the bondability of used full-length hay, or hay particles for urea formaldehyde (UF) resin. A comparison of the physical and mechanical properties was assessed. The vertical density profile of hay panels made from treated hay reached smaller differences between surface and core density. Full-length hay panels reached the higher average values of the equilibrium moisture content (EMC), due to the structure. The bending properties of panels made of treated hay particles showed improvement, with modulus of rupture being 3.5 times higher, and modulus of elasticity 2.6 times higher than that of the untreated hay particles. Thickness swelling after 48 hours decreased for the NaOH-pretreated hay panels.

Automated summary

Agricultural resources, such as hay, have the potential to be a substitute or replacement for wood, especially in countries with limited wood resources or during times of economic instability in the wood market. Previous research has explored various sources but had not considered hay. By soaking in NaOH, the bondability of hay can be improved for manufacturing panel products. This study found that treated hay panels had improved density profiles, higher equilibrium moisture content, and enhanced bending properties compared to untreated hay panels.