Laccase-Enzyme Treated Flax Fibre for Use in Natural Fibre Epoxy Composites.

Natural fibres have a high potential as reinforcement of polymer matrices, as they combine a high specific strength and modulus with sustainable production and reasonable prices. Modifying the fibre surface is a common method to increase the adhesion and thereby enhance the mechanical properties of composites. In this study, a novel sustainable surface treatment is presented: the fungal enzyme laccase was utilised with the aim of covalently binding the coupling agent dopamine to flax fibre surfaces.

Enhanced Interfacial Shear Strength and Critical Energy Release Rate in Single Glass Fiber-Crosslinked Polypropylene Model Microcomposites.

Continuous glass fiber-reinforced polypropylene composites produced by using hybrid yarns show reduced fiber-to-matrix adhesion in comparison to their thermosetting counterparts. Their consolidation involves no curing, and the chemical reactions are limited to the glass fiber surface, the silane coupling agent, and the maleic anhydride-grafted polypropylene. This paper investigates the impact of electron beam crosslinkable toughened polypropylene, alkylene-functionalized single glass fibers, and electron-induced grafting and crosslinking on the local interfacial shear strength and critical energy release rate in single glass fiber polypropylene model microcomposites.

Why Should the "Alternative" Method of Estimating Local Interfacial Shear Strength in a Pull-Out Test Be Preferred to Other Methods?

One of the most popular micromechanical techniques of determining the local interfacial shear strength (local IFSS, ) between a fiber and a matrix is the single fiber pull-out test. The values are calculated from the characteristic forces determined from the experimental force⁻displacement curves using a model which relates their values to local interfacial strength parameters. Traditionally, the local IFSS is estimated from the debond force, , which corresponds to the crack initiation and manifests itself by a "kink" in the force⁻displacement curve.