Swirl mat- and long discontinuous fiber mat-reinforced polypropylene composites - Status and future trends

Polypropylene (PP) composites with glass and natural fiber mat reinforcement (GMT-PP and NMT-PP, respectively) are widely used in different applications, competing with metallic sheets and thermoset polymer composites. Their production occurs via melt impregnation, slurry deposition and various textile architecturing processes that lead to either consolidated or non-consolidated preforms. These preforms are then converted into final parts by hot pressing. The "traditional" GMT-PP composites are nowadays faced with a great challenge because of the introduction of long fiber reinforced thermoplastic (LFT) composites produced on- or off-line. This paper gives a brief survey on the manufacturing, processing, properties and application of GMT and GMT-like systems and it concludes by describing some of the future trends, especially in the fields of material and process developments.