Talcum Particle Reinforced Thermoplastics - Part I: Influence of Processing Conditions and Experimental Characterization

The properties of thermoplastic polymers considerably depend on the process of moulding, irrespective of the geometry of the part and the used raw polymer. Both, the structure of the polymer resulting from moulding and the weld lines occurred because of the complexity of the part, may show a large influence on different part properties. For analysing the influence of injection moulding on the resulting structural part properties, plates with different processing conditions are fabricated with Hostacom XBR169G, a polypropylene (PP) filled with rubber and talc, and Bayblend T65XF, a blend of polycarbonate (PC) and acrylonitrile butadiene styrene (ABS). The varied conditions are the melt temperature and the injection velocity. Afterwards different test samples, longitudinal and lateral to flow direction, are milled out of the fabricated plates. Using this extracted test samples, the true deformation and failure behaviour are measured by uniaxial tensile tests at different test temperatures and strain rates. The complex deformation behaviour is determined by the method of grey-scale correlation. The analysis of uniaxial tensile tests shows anisotropic effects depending on the preparation direction of the specimen, i. e. in stress behaviour as well as in Poisson’s ratio for Hostacom XBR169G. Also machine settings affect the anisotropic behaviour. A high mass temperature in combination with a slow injection speed leads to differences in stress level and Poisson’s ratio. At low mass temperatures and high injection velocities, the plates solely show isotropic behaviour. In all experiments, the strain at rapture is not influenced by processing conditions or preparation direction. For Bayblend T65XF no anisotropic behaviour is found.