JEC COMPOSITES MAGAZINE - Issue #46 - January/February 2009 - 41

Prepreg A novel prepreg material combining natural fibres with a furan resin Composite materials derived from renewable resources have received considerable interest in recent years due to the ever-increasing concern about the depletion of the earth’s fossil resources. The combination of natural fibres and bio-derived resin systems is a potential route to manufacturing bio-composite materials for mass transport, automotive and construction applications. This article describes the development of a new biomass-based prepreg system based on furan resins and natural fibres. Furan-natural fibre prepreg The applicability of biomass-based furan resins in composite manufacturing was evaluated in the recent BIOCOMP project, an integrated project for SMEs supported by the European Commission’s Sixth Framework Programme. A primary objective of the BIOCOMP project was to develop high-performance composite materials entirely derived from renewable sources using a new family of furan-based resins reinforced with continuous, aligned natural fibres. This goal was reached by the development of furan-natural fibre prepreg technology. The possibility of exact fibre placement in the direction of applied loads combined with a high fibre volume fraction is the main engineering characteristic of existing prepreg materials. Natural fibre prepreg materials with fossil-based resins like epoxy have been reported in commercial praxis. With minor adjustment of the curing system and characteristics, it is possible to formulate a furan resin for use as a matrix material in natural fibre prepregs. Furan resins are generally cured by acid hardeners which trigger a polycondensation reaction, leading to a highly cross-linked polyfurfuryl alcohol network. It is well known that natural fibres – being lignocellosic materials – can be degraded in hydrolytic conditions, catalyzed by both acid and alkaline chemicals through various pulping reactions. In order to compatibilize the acid curing mechanism of a furan resin with natural fibres, a novel catalytic system has been developed which is able to cure the resin whilst protecting the natural fibre from any degradation reaction. The resulting Furolite furan resin is a ready-mixed resin which is curable at temperatures above 100°C (Fig. 1). 1 2 3 4 1- HANS E. HOYDONCKX, BUSINESS DEVELOPMENT MANAGER, TRANSFURANS CHEMICALS 2- GUNTHER SWITSERS, PROCESS AND PRODUCT DEVELOPMENT ENGINEER, TRANSFURANS CHEMICALS 3- BRENDON M. WEAGER, TECHNICAL MANAGER, NETCOMPOSITES LTD 4- ELAINE L. ARNOLD, BIOMATERIALS R&D ENGINEER, NETCOMPOSITES LTD uran resin systems have long been used as thermoset binders for aggregates in the foundry and refractory industries. The success of furan resins in these industries has been sustained by their high temperature resistance in such demanding applications. For example, furan resins are used in a variety of binder systems in the foundry industry, including “furan no-bake” resins, heat-curing and gas-hardened systems. F TransFurans Chemicals recently developed a new range of furan resin systems under the trade name BioRez and Furolite. These resins originate from furan chemical technology, though they are based on prepolymer molecules of furfuryl alcohol. Furfuryl alcohol is a renewable alcohol produced from furfural, which is formed by the acid-catalyzed digestion of hemicellulosic sugars in biomass. With biomass as the sole raw material, it is a renewable and CO2-neutral chemical. The use of this prepolymer matrix structure provides the backbone for formulating a wide variety of cold or hot curing thermosets for a range of applications. BioRez and Furolite resin systems can be applied in different composite manufacturing processes including hot compression moulding (spray-up, BMC, SMC, etc.), vacuum infusion, resin transfer moulding (RTM), hand lay-up and filament winding. Furan resins offer a number of interesting properties such as high stiffness, fire resistance and chemical resistance. Prepreg production technology Standard textile impregnation equipment was used to produce this furan prepreg. In the first step, the natural fibre textile material is impregnated with (water diluted) furan resin and the No46 January-February 2009 / jec composites magazine 41

JEC COMPOSITES MAGAZINE - Issue #46 - January/February 2009

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #46 - January/February 2009