Effects of ionic liquid on the rheological properties of wood flour/high density polyethylene composites

Wood flour was treated with an ionic liquid, 1-(2-hydroxyethyl)-3-methylimidazolium chloride ([Hemim]Cl), to various weight percent gains. The treating effects on the rheological properties of the resulting wood flour/high density polyethylene (HDPE) blends were investigated using a Haake microcompounder and torque-, capillary-, and rotational-rheometer, respectively. Treatment with [Hemim]Cl caused a decrease in the crystallinity and an improvement in the thermoplasticity of wood flour. At low processing speeds, the melt torque and viscosity increased with increasing [Hemim]Cl content; while at high speed, they decreased or remained the same. [Hemim]Cl can broaden the processing window of wood flour/HDPE composites with stable flow and smooth product surfaces. The dynamic rheological results show that storage and loss moduli and complex viscosity of the composite melts increased with increasing [Hemim]Cl content.