Bio-composites made from pine straw
Pine straw is renewable natural resource that is under-utilized. The objective of this study was to evaluate the physical and mechanical performances of pine straw composites. Three panel density levels (0.8, 0.9, 1.0 g/cm2) and two resin content levels (1% pMDI + 4% UF, 2% pMDI + 4% UF) were selected as treatments. For the pine-straw-bamboo-fiber straw fibers were treated with a container blender, which reduced the fiber sizes and increased the roughness of fiber surfaces. The bending and IB strength properties of the pine straw boards meet the requirements of Class 5 of the voluntary product standard PS 60-73. Strength properties of the pine straw boards were positively correlated with the blending time. The waxy cutin on the surface of the needles was a barrier to the bonding quality and blending in the container blender was helpful in the removal of cutin from material surfaces. Linear relationship was found between the internal bond (IB) strength and board density. Higher pMDI resin content led to greater slope values of the Ib-density regression lines. The addition of strong bamboo fibers significantly increased the bending and interenal bond strength of the pine straw composites.