Processing and properties of glass/polypropylene in long fibre compounding extrusion

Abstract

Processing parameters for the direct compounding of glass fibres and polypropylene (PP) in a twin screw extruder and their influence on the extruded material are investigated. For each extruded material, the fibre damage was determined by analysing the fibre length distribution. In addition, specimen plates were pressed for tensile and impact tests. Initially, PPs with different viscosities were tested, resulting in higher fibre lengths for the high viscosity PP but lower mechanical properties. At this point, fibre damage mechanics were discussed. Experiments with a high shear and a conservative compounding screw configuration exhibited close results for fibre lengths, thus indicating high fibre damage even by standard elements. A high screw rotation rate generated much smaller fibres than a low one, as expected, but exerted little effect on the mechanical properties. In addition, the difference of varied fibre contents was negligible in the fibre length distributions.

Keywords:

• Extrusion
• Long fibre reinforcement
• Fibre length
• LFT

Material processing and characterisation were performed at the Institut für Verbundwerkstoffe GmbH, Kaiserselautern, Germany.

Notes

This paper is part of a special issue on Latest developments in research on composite materials