Effects of Processing Conditions on the Structure and Fibre Length Distribution of Glass Fibre Reinforced Polypropylene / Polyamide 6.6 -Blends
Päivi Lehtonen, H.G. Fritz
Institut fuer Kunststofftechnologie (IKT), University of Stuttgart
Germany
Keywords: Blends, Structure, Fibre Length
The influence of the processing conditions on the structure and fibre length distribution of glass fibre reinforced Polyamide (PA) 6.6 / Polypropylene (PP) - blends was studied. PP/PA- blends are immiscible systems without the use of a third component as a compatibilizer. Due to the non-polar nature of the PP a coupling agent is also needed to intensify the interactions between fibres and matrix. In our study the use of a compatibilizer masterbatch was replaced by a direct grafting of the whole PP - matrix with maleic anhydride (MAH).
Blends with different composition ranges of PP and PA 6.6 were generated by means of a twin-screw extruder. PP/PA 6.6 ratios were varied in such a way to realise also co-continuous phase structure. The amount of glass fibres in the blends remained constant but the type of the glass fibre rovings and the diameter of the filaments were varied. The influences of compounding conditions on the fibre length distribution and on the resulting morphology of the blends were investigated using different screw configurations and different sets of processing parameters. The fibre length and fibre length distribution were characterised and their influence on the morphologies of such blends was analysed by means of scanning electron microscopy.
The physical properties of the long glass fibre reinforced blends are strongly determined by the average length of the fibres and the adhesion between fibres and matrix. In order to gain more information about these interactions, mechanical and thermal properties of the blends were also tested.