Critical Fibre Length and Apparent Interfacial Shear Strength of Single Flax Fibre Polypropylene Composites

Abstract

The stress transfer in, both elementary and technical, single flax fibre polypropylene composites is studied by determining the critical fibre length and the apparent interfacial shear strength. The influence of improved fibre-matrix interaction is reported and the results are compared with data from literature. The study indicates that the critical fibre length for elementary flax fibres is equal to or even higher than the flax fibre lengths found after extrusion and injection moulding processes. Furthermore, addition of maleic anhydridy modified polypropylene to the matrix results in an apparent interfacial shear strength for elementary flax fibres close to the shear yield strength of the matrix, for technical fibres the interfacial shear strength is somewhat lower.