INFLUENCE OF BLENDING PROTOCOL ON THE THERMAL AND MECHANICAL PROPERTIES OF HDPE/LLDPE BLEND-BASED NANOCOMPOSITES

The purpose of this work was to investigate the effect of organoclay and compatibilizer agent (LLDPE-g-MA) content on the thermal and mechanical properties for nanocomposites based on a high density polyethylene/linear low density polyethylene blend. The nanocomposites with 2.5, 5.0 and 7.5 wt% of organoclay were produced by melt compounding in a twin-screw extruder. The effect of two blending protocols was also investigated. In the first blending protocol LLDPE and LLDPE-g-MA were first reinforced with organoclay and then this nanocomposite was later blended with HDPE, and the in the second blending protocol LLDPE-g-MA was mixed with organoclay first and then this masterbatch was diluted with HDPE and LLDPE. The nanocomposites were analyzed by WAXD and TEM. The thermal characterization was performed by DSC and DMA, and the mechanical properties were evaluated by tensile properties and three point bending tests. It was shown that the introduction of a maleated compatibilizer was required to improve the organoclay dispersion in the nanocomposite. The addition of organoclay increased the thermal stability and mechanical for all the nanocomposites with respect to the blend. The addition of compatibilizer agent improved the interactions between the organoclay and polymeric matrix and inhibited the mobility of the segments of polymer chains that led to an increase in Tg of the nanocomposites. The organoclay acted as a nucleating agent, increasing the crystallinity with the increase of the level of organoclay. Moreover, the addition of LLDPE-g-MA inhibited the nucleation and/or crystal growth and decreased the crystallinity.