Sheet extrusion and thermoforming of discrete long glass fibre reinforced polypropylene

The present paper summarises the main aspects and the developments in sheet extrusion and thermoforming of discrete long glass fibre (LGF) composites using the SAFIRE (Self Assembling Fibre Reinforcement) technology. During e xtrusion the long glass fibres are organised into coherent fibre mats which persist into the solid state, and are able to withstand the deformation pr ocess that takes place during thermoforming. A process analysis has been pe rformed for extrusion and thermoforming indicating the main individual oper ations. Both processes have been studied with regard to their performance w ith the materials used in the studies, namely polypropylene homo- and copol ymer, with and without LGF reinforcement. Significant improvements in mecha nical properties relative to the unreinforced materials have been found for the extruded sheets and the thermoformed products. Major improvements in p rocessability relative to unreinforced PP have been found for the LGF mater ials. These are discussed in terms of the coherent fibre mat concept. (C) 2 000 Elsevier Science Ltd. All rights reserved.