The Esprit project has completed its first year and a half of research and has carried out an extensive programme of locating, manufacturing and characterising the base materials from which the flowing Self Reinforced Plastics will be made. These are variations on Self Reinforced Polyolefins (srPO), Self Reinforced Nylons (srPA) and Self Reinforced Polyesters (srPet) and some early processing trials have been carried out in order to measure critical temperatures and shrinkage characteristics.
Partners have made excellent progress in the pultrusion of commingled yarns into a continuous rod which is subsequently chopped into pellets for flow moulding applications. A custom built line has been running successfully which can produce 5kg/hr of pellets derived from PA, PBT, PP and PET combinations. A special cutter has been developed as these thermoplastic reinforcements present very different characteristics to traditional carbon/glass reinforcements.
The Esprit project now has a stable basis to efficiently make pellet samples derived from the many modified matrix and reinforcement raw materials being generated by other partners.
A polypropylene based polymer fibre reinforced composite has been created with an extremely high impact strength. The composite, containing relatively long fibres, shows an unusual but highly attractive combination of high modulus, high strain at break, high impact resistance and low notch sensitivity. These material contain fibres up to 10 mm and can be injection moulded into complex shapes – the challenge being to maintain fibre reinforcement integrity through the whole process. The optimum processing of the new materials is acheived by standard machines adapted in the areas of plastification, injection phase, the heating of the polymer and the temperature control in the barrel and mould.