THE INFLUENCE OF NANO-FILLER ON RHEOLOGICAL PROPERTIES OF POLYMER MELTS AND BLENDS

Abstract

Studying  the  influence  of  additives  of  nano-sized  aluminium  oxide  on  the  patterns  of Polypropylene (PP) and mixture PP/CPA (copolyamide) melt flow. 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. 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 Al 2 O 3  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 structure-
formation 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.