High Load Polypropylene Composites

Polypropylene composites with high content of inorganic filler or short glass fiber could be produced after compounding in a single screw Buss technology or in a twin-screw extruder. Specific formulations were properly prepared to guarantee an adequate processability for injection molding or extrusion. Polypropylene matrix was a proper combination of low and high melt flow grades in the range of about 3-12 g/10min and 500-2300 g/10min respectively. High content polypropylene composite containing up to 60% by wt. of talc, 80% of calcium carbonate or 65% of short glass were produced using a relatively low viscosity matrix. Good flow-ability and processability for all compositions were evidenced. ISO specimens and large plates obtained after injection molding evidenced the increase of stiffness, strength, toughness at low temperature, and reduction of shrinkage. Deep investigation was conducted on glass fiber composites at 40-50-60%. (DSC, TGA, SEM, DMA, fiber distribution, flammability evaluation, and comparison). Results have been discussed and correlated with the compositions.