Rheology, Mechanical and Thermal Properties of C18-CNT/LDPE Nanocomposites

Abstract

Abstract Nanocomposites of low density polyethylene (LDPE)/C18 modified multi wall carbon nanotubes (C18-CNT) were prepared by melt blending. The effect of C18-CNT loading and compatibilizer (maleic anhydride modified polyethylene, MAPE) on the morphology, mechanical, thermal and rheological properties of LDPE was studied. FE-SEM images of nanocomposites show reduced agglomeration of the in LDPE/C18-CNT in comparison with uncompatibilized C18-CNT. For uncompatibilized nanocomposites, yield strength and Young's modulus increased with loading of C18-CNT. Ultimate strength, show improvement up to 2 wt% loading. However, percent elongation and toughness were reduced for C18-CNT at all loadings. Apart from elongation and toughness, addition of compatibilizer improved all mechanical properties as compared to pure LDPE and nanocomposites without compatibilizer. Percent crystallinity shows a correlation with Young's modulus. Both, Young's modulus and total crystallinity increased with C18-CNT loading and further increase with the incorporation of compatibilizer was observed. Results of phase angle suggest no presence of network. Also, addition of C18-CNT did not increase strain hardening, maintained extensional viscosity and time of break up to 1.5 s−1 Hencky rate. The C18 modifier is viewed to act similar to a long chain branching on linear polymers. The C18 modification of CNT resulted in reduced viscous and elastic properties of the composites. In turn, this is expected to lead to enhancement in the processing of these composites. Overall, compatibilized C18-CNT resulted in improved mechanical properties and better processing behavior.