Influence of surface treatment on strength and adhesion between flax natural fibres and a thermoplastic matrix

Abstract

Composites of thermoplastics reinforced with natural fibres have been widely used in recent years. Natural fibres are considered as a greener substitute due to their advantages over conventional fibres such as low cost, low density, high availability, excellent mechanical properties, biodegradability and to be environmentally friendly. However, they present an important limitation, the weak interaction between fibres and matrix. Therefore, surface treatments on natural fibres are very common in order to increase wettability and surface energy and thus to promote good fibre-matrix adhesion. The objective of this work is to study adhesion between flax fibres, under different surface treatments, and LDPE matrix. Pull-out tests were carried out with flax fibres yarns treated with low pressure plasma, atmospheric pressure plasma torch,silane coating and different alkaline treatments as well as with untreated fibres.  Afterwards,  composites materials were manufactured using unidirectional flax fabric and LDPE in a hot plate press. Finally, mechanical properties of each composite material were evaluated by tensile tests using an universal test machine. In this way, a greater interaction between LDPE and flax fibres can be compared with the final properties.

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