Method for making variable cross section pultruded thermoplastic composite articles: O'Connor, J.E. (Phillips Petroleum Company, Bartlesville, OK, USA) US Pat 5 026 447 (25 June 1991)

Abstract

The aim of this work is to optimize the production of new continuous carbon fibers reinforced polypropylene matrix pre-impregnated materials (towpregs) continuously processed by dry deposition of polypropylene (PP) powder by our own developed dry coating line. The processing of the produced towpregs by pultrusion, using a prototype equipment, was also optimized. The optimization of both processes was made by studying the influence of the most relevant processing parameters in the final properties of the produced towpregs and composites. The method of Taguchi/DOE (Design of Experiments) was used to allow the determination of the optimal processing windows. The possibility of using maleic anhydride as compatibilizer for polypropylene reinforced carbon fiber composites (CF/PP) was also analyzed. A pre-consolidate tape was produced by the melting cross-head extrusion process and its proprieties compared with those of towpregs. Finally, towpregs were characterized by scanning electron microscopy (SEM) and visual analysis. Their polymer mass contents were determined and the final pultruded composite profiles were also submitted to tensile, interlaminar, flexural, calcination and optical microscopy tests.