Engineering and characterisation of the interface in flax fibre/polypropylene composite materials. Part II. The effect of surface treatments on the interface

Natural fibres have attracted much attention recently for use as reinforcing agents in composite materials. However, even though natural fibres possess many advantages over glass fibres, such as lower density, lower cost and recycleability, they are not totally free of problems. Natural fibres are comprised mostly of cellulose, a highly hydrophilic macromolecule with strong polarity and, as a result, problems of compatibility with very apolar matrices (e.g. polyolefins) almost certainly arise. Surface treatments, although having a negative impact on economics, may improve the compatibility and strengthen the interface in natural fibre composite materials. In Part I of the present study two such surface treatments, acetylation and stearation, have been developed and applied to flax fibres. In this second part, the effect of these treatments upon the interface of flax fibre/polypropylene composites is assessed by means of fragmentation tests. It has been found that both treatments led to improvement of the stress transfer efficiency at the interface, and both applied treatments were optimised, accordingly. (C) 2002 Elsevier Science Ltd. All rights reserved.