Natural fiber-reinforced plastics composites: long-term physico-structural performance in façades

Abstract

Mixing fossil-based plastics with wood fibers is an effective measurement for a more responsible use of scarce crude oil resources. However, products made from such wood-polymer composites (WPC) not necessarily show similar properties as if made from neat plastics specifically if intended for structural outdoor use such as façades. This papers reports from a multi sampling of three WPC compounds showing different surface finishings. After one year natural weathering in Central Europe, physico-mechanical properties were determined by density and water uptake as well as impact and bending strength in dry and saturated state. It was found that brushing a WPC`s surface potentially accelerates ageing by unhindered humidity- and UV-penetration but this effect is compensable by increasing the compound`s density. Alternatively, negative consequences from a high fiber content usually resulting in low density can be offset by a weather protecting co-extruded surface layer. Such a compound revealed lowest decline in impact and bending strength and consistent surface appearance over the weathering period. This particular finishing obviously best supports durability and eco-friendliness of fiber-reinforced plastics composites.