Influences of moisture absorption and chemical treatments on the resin flow characteristics of natural fibre nonwoven mats

摘要

A major challenge for the use of natural fibres in polymeric composites is their incompatibility with commonly used matrices, causing weak interfaces of the final composites. Many surface treatments to natural fibres have been proposed to eliminate or reduce these problems. In this paper, we evaluate the influences of three commonly used natural fibre chemical treatments on the resin flow characteristics of flax fibre nonwoven mats in a vacuum-assisted resin transfer moulding process. The alkalization treatment significantly increases the in-plane permeability and flow anisotropy of the natural nonwoven mat due to changes in fibre diameter, fibre surface tension and mat structure. The effects of silane and acetylation treatments on resin flow are much smaller. It is well known that in comparison with glass fibre, natural fibres can absorb a large amount of moisture from surrounding air. The absorption of moisture causes a considerable reduction in the in-plane permeability of natural fibre nonwoven mats.