Semi-finished thermoplastic composites-realising their potential

Thermoplastic composites are second-generation polymer composites. Their late appearance, at the end of the 1970s, can be blamed on their high melt viscosities, which created an impregnation problem for the early developers. Although thermoset composites were by then well established, the new materials were felt to have great commercial potential, which should lead in the long run to their domination of the polymer composite market. Foremost among their attractions was their suitability for use as semi-finished materials (SFM). These expectations have turned out to be wildly optimistic. Insufficient attention, during the 1980s, to the processing technology necessary for such volume production, resulted in a wholesale withdrawal of the major material suppliers from the market in the economic downturn of the early 1990s. In 2000, ThermoformNet, an EPSRC funded network, was set up in response to renewed interest in the materials. Since considerable emphasis has been given to the issue of SFMs, in the course of the network activities, this paper reviews the subject from an historical perspective before taking stock of the technology and outlining likely future developments. Particular attention is given to sheet materials.