Blends and composites based on polypropylene and a thermotropic liquid crystalline polymer
Blends of polypropylene (PP) and liquid crystalline polymer (LCP) (Vectra A 950) processed without melting the LCP were compared with conventional melt processed blends. In a first stage, PP was blended with 20 wt.% of LCP in a twin-screw extruder with the take-up speed varied to achieve blends with different LCP fibre dimensions. In the second stage these blends were processed both below and above the T m of the LCP by extrusion and injection moulding. At lower temperatures (180-200°C), where the material was processed without melting the LCP, a real composite structure was formed with solid LCP fibres in the PP matrix. When processed above the T m of the LCP (280°C) all the material was molten during processing and a composite-like blend morphology was created in-situ during cooling of the oriented melt phase