Nanoclay is increasingly used in plastics to enhance mechanical properties at a very low level of addition. Generally nanoclay is incorporated at less than 5% level. It eliminates surface melt fracture and postpones the critical shear rate for the onset of gross melt fracture to significantly higher values depending on resin type, temperature and additive concentration (typically 0.05 to 0.5 wt%). However at higher levels of about 5%, the beneficial effect on processability of linear olefin polymers like that of LLDPE, HDPE and PP is eliminated. It is also observed that the combination of nanoclays with traditional processing aids such as fluoropolymers produce an enhanced processing aid that can increase the critical shear rates for the onset of melt fracture to levels much higher than the individual constituents when they are used independently.
(A publication of Society of Plastics Engineers, USA)