Technologies and Engineering

The influence of nano-filler on rheological properties of polymer melts and blends

Purpose. Studying the influence of additives of nano-sized aluminium oxide on the patterns of Polypropylene (PP) and mixture PP/CPA (copolyamide) melt flow. Methodology. The mixtures were obtained by the prior injection of the nano-filler to the PP melt with the further mixing of granula with CPA on the worm-disk extruder. Viscosity (η) of melts was examined by the method of capillary viscometry and the elasticity was studied by value of extrudate equilibrium swelling. The melts ability to longitudinal deformation was evaluated by the maximum stretch rating. Findings. It was established that effective viscosity and ability to longitudinal deformation of PP melt expectedly increase, while elasticity decreases in all the range of the nano-additives concentration. The injection of nano-particles Al2O3 into the PP/CPA mixture preconditions the decrease of the melt viscosity. In the content of additive in 0,1 weight % the so-called effect of small additives takes place, meaning that the viscosity reaches the maximum value. It was shown that modified systems are characterized with the increased elasticity and spinning value, which is connected with the change of the processes of structureformation of PP in CPA matrix under the influence of the nano-additive. Originality. The decrease of viscosity of melts of nano-filled compositions in comparison to original elements bears evidence of the modification of the mechanism of their flow, meaning the transition from the move of segments of macromolecules in the flow to the stratified (layer-by-layer) move of separate phases. Practical value. The established patterns of nano-filled mixtures flow will contribute to the right choice of technological parameters of their processing, as well as they may be used in the process of modernizing the existing technological equipment and designing the new one

polymers, mixtures, nano-additive, viscosity, elasticity