JOURNAL OF NANOSTRUCTURED POLYMERS AND NANOCOMPOSITES 8/1 5-11 NOVEL REACTIVE BICOMPONENT FIBRES: MATERIAL IN COMPOSITE MANUFACTURING YVONNE AITOMAKI 1 , BENGT HAGSTROM 2 , RUNAR LANGSTROM 1 , PATRIK FERNBERG 1 'Swerea SICOMP AB, Box 271, SE-941 26 Pitea 'Swerea !VF AB, Box 104, 431 22 Mi:ilndal Received 2 December 2011; accepted 2 April 2012 Abstract The hypotheses that reactive uncured, thermoset bicomponent fibres can be prepared and mixed with reinforcing fi- bres and ultimately used in preparation of a composite was tested and is described. It is thought that such fibres have the two potential advantages: ( 1) to enable manufacturing with pai1icle doped resins e.g. nanocomposites which add functionality to composites and (2) increased efficiency of structural composite manufacturing by increasing the level of automation. The structure of the thermoset fibres comprises of a sheath of thermoplastic and a core of uncured the1moset resin. Once manufactured, the fibres were wound with a reinforced fibre onto a plate, consolidated and cured. The resulting composite was examined and compared to other composites made with the same manufacturing method from commercially available materials. The results show that a laminate can be produced using these reactive bicomponent fibres. The resin system successfully impregnates the reinforcing carbon fibres and that the thermoplas- tic separates from the epoxy resin system during consolidation. In comparison to reference material, the bicomponent laminate shows promising characteristics. However, the processes developed are currently on a lab-scale and consid- erable improvement of various bicomponent fibre properties, such as the strength, are required before the technology can be used on a larger scale. 1. Introduction Fibre reinforced polymeric composites (FRP) can combine weight advantages as well as increase functionality in structures. However, manufacturing these composites is slow compared to current metal fonning techniques hence the current emphasis on increasing the automation of the manufacture of these types of composites. The concept investigated here is the use of a commingled reactive bicomponent fibres and reinforcing fibres, as a means of manufacturing fibre composites. The bicomponent fibre is made up of a sheath of thermoplastic surrounding a core of reactive resin. Bicomponent matrix fibres lie next to the reinforcing fibres, functioning similar to prepreg from a composite processing view. As with thermo- setting prepregs the composite is formed once the resin is cured by the application of heat and pressure. Potential advantages compared to prepregs are the increase in the ease of handling and storage which, combined with a lack of tack, is potentially better for robotic handling. Bicomponent fibres also provide a means of introducing the resin into the fibres quickly. These advantages can increase the automation ofFRP manufacturing leading to it being more efficient, reli- able and quicker. Another advantage is that it can enable the in- corporation of particle modified matrix system or nanocomposites e.g. to improve fire resistance of FRP. Chou et.al. [!] presents a number of results that demonstrate various positive synergistic effects when carbon-nanotubes are combined with traditional fibre reinforcements. Problems of practical nature associated with manufacturing of particle modified FRP however exist such as difficulties in achieving good dispersion, problems due to high viscosities of nanocomposite resins and filtering of the nano- reinforcement. Filtering problems are particularly severe in situations where flow paths are long e.g. in Resin Transfer Moulding [2]. FRP manufactur- ing with commingled reinforcing and bicomponent fibres implies shortest possible flow lengths during impregnation and thus offers a potential solution to the viscosity and filtration problems. The bicomponent fibre structure is a means of manufacturing thennoset fibres and comprises of a sheath of thermoplastic and a core of uncured ther- moset resin. Uncured thermoset fibres have not been developed but partial cured fibre have been extruded and cured to test the effects of carbon nanotubes in resins [3]. Thermoplastic matrix fibres commingled with reinforced fibres are commercially developed and are t!Je basis of products such as Twintex (Owen 5