ELECTRON-BEAM PROCESSING OF WOOD FIBRE REINFORCED POLYPROPYLENE

Abstract

High aspect ratio (LID> 100) cellulosic fibres can be used as efficient reinforcement for different thermoplastics. A procedure has been developed for wood fibre reinforced thermoplastic composites, applying a relatively small amount of reactive additive that compatibilize the synthetic and natural polymer components. Electron Beam (EB) treatment is a productive method of creating active sites on both matrix polymer and fibrous reinforcement, bound together through reactive additive. The EB-processed, wood fibre reinforced polypropylene composite has not only a high modulus of elasticity, but also significantly higher flexural and tensile strength and improved thermal tolerance over the conventional wood fibre - polypropylene blends. The relatively low melt viscosity of our wood fibre reinforced polypropylene makes it easily processed not only by extrusion but also by injection molding. In the procedure recycled raw materials (e.g. fibres from recycled paper pulp or byproducts of the woodworking industry) can be used and the product is a fully recyclable composite. The original procedure elaborated in Hungary was further developed and tried out in pilot scale at Canada. EB treatment, extrusion and thermoforming of the extruded sheets has been performed and applied to produce internal automobile parts, with the co- operation of Atomic Energy of Canada Ltd. (AECL) Whiteshell Research Laboratories. Technical feasibility and improved product quality have been demonstrated. The justifi- cation of high upfront investment costs of the EB processing line remained in discussion.