Utilizing straw as a filler in thermoplastic building materials

A recent addition to the list of composite building materials is plastic lumber. While utilizing recycled plastics as building materials promotes recycling, plastic lumber itself is a poor replacement for solid wood. Research is underway to improve the mechanical properties of wood/polymer composites. This report investigates the use of Willamette Valley rye grass straw as a filler in the commodity plastics polyethylene (PE) and polystyrene (ps). Since recycled plastics are often mixtures, blends of PE and ps were studied. A compatibilizer was used to improve the properties of the plastic blends. Composites of blends of plastics filled with straw showed a linear relationship in strength and stiffness. Straw performs similarly to wood as a filler in these systems. In composites containing only one plastic, the performance of straw as a filler seemed slightly superior to wood in polyethylene and slightly inferior in polystyrene. The properties observed here compare favourably to those of commercial products and suggest that improvements in these products are possible. Copyright (C) 1996 Elsevier Science Ltd.