Enhancing the performance and processibility of rice hull - high-density polyethylene composites

Wood Fiber Reinforced Plastic (WFRP) represents an expanding segment of the plastic and composite market. However, the poor stress transfer resulting from the incompatibility between polyolefin and natural fibers limits this material's use in structural applications. Interface modifiers and viscosity modifiers are often used to enhance mechanical and rheological properties respectively. This study investigates the interaction between these interfacially active additive chemistries in high-density polyethylene composites containing rice hulls. A design of experiments was performed to investigate four functionalized polyethylene-based interface modifiers and four viscosity modifiers and their interactions. Synergistic as well as antagonistic interactions were observed between various compounds from these two classes of additives. Synergy between acrylated maleated polyethylene-based interface modifier and partially halogenated polyethylene-based viscosity modifier was further investigated to elucidate molecular level interactions. Dynamic mechanical analysis (DMA), time of flight secondary ion mass spectrometry (TOF-SIMS), and chemical analysis of the WFRP were carried out to explain the mechanisms of interaction. Application of response surface method (RSM) for the optimization of WFRP formulation is also demonstrated.