Expansion in the use of natural fibres for composite applications

Over the last several years there has been a re-emergence of natural fibres as an alternative type of reinforcement for composite applications. For example, flax, hemp, sisal and jute fibres have been introduced as a reinforcement for thermoplastic automotive parts. Addition of these fibres not only increases the mechanical properties, but they are lighter than traditional reinforcements, and allow for the parts to be fully recyclable. Currently, natural fibres are predominantly supplied in a non woven or processed form and are generally not of a high purity or quality. Today, it is standard to find hemp fibres mixed randomly in a polyurethane resin for table top applications, flax fibres mixed with thermoplastics to produce interior liner panels for car doors and roofs, and straw fibres combined with a polyurethane resin for shelving and floor applications. This paper compares the properties of natural fibres with fibreglass fibres, a staple reinforcement material for composite applications. Further, it describes existing material forms, illustrating their properties when bound with a resin and commenting on the appropriateness of natural fibres for replacing these products. Current and planned Canadian efforts to further develop and introduce these natural fibres are described together with the shortfalls that have to be overcome. Examples are provided and opportunities discussed to demonstrate that these materials are potentially a reliable and realistic alternative.