High-density polyethylene/halloysite nanocomposites: morphology and rheological behaviour under extensional and shear flow

摘要

The paper describes the preparation of High Density Polyethylene [HDPE]/Halloysite Nanotube [HNT] nanocomposites by melt compounding HDPE with varying amounts of HNTs (ranging from 1 to 10% w/w) in the absence and presence of MA-g-HDPE as compatibiliser using co-rotating twin screw extruder. The effect of HNT loading and compatibiliser amount on morphology and rheological properties was investigated. Melt strength and drawability were determined using Rheotens whereas extensional viscosity was calculated from (i) Wagner's master curve (using Rheotens data) and (ii) modified Cogswell method (using convergent flow analysis from capillary rheometer data). In HDPE/HNT composites, melt extensional properties (melt strength, drawability and extensional viscosity) increased slightly with increase in HNT concentration up to 5 % w/w followed by a decrease as HNT concentration was increased to 10 % w/w. On the other hand all these properties enhanced significantly in the presence of compatibiliser i.e. in HDPE/MA-g-HDPE/HNTs nanocomposites. Rheological studies form capillary rheometer showed marginal increase in the high shear viscosity at 10 % w/w filler loading. Both Complex viscosity and storage modulus in oscillatory rheometry were highest for nanocomposites prepared using 10 % w/w HNT and reduced slightly after incorporation of compatibiliser.