Effects of liquid crystal polymer and organoclay addition on the physical properties of high-density polyethylene films

In this study, physical properties of high-density polyethylene (HDPE) films, blended and reinforced with small amounts of liquid crystal polymer (LCP) and organoclay (org-clay), were investigated by employing different characterization tools such as X-ray diffractometer, scanning electron microscope, differential scanning calorimetry, rotational rheometer, dynamic mechanical analysis, and gas permeability measurements. Viscoelastic properties of samples were quantified by applying several test procedures in melt and solid-state dynamic measurements. It was found that rigid LCP droplets were dispersed well into HDPE matrix and improved the melt elasticity and creep resistance of HDPE. Compatibilizer and org-clay loading into HDPE/LCP blends yielded formation of smaller LCP droplets and reduced mean relaxation time and shear modulus values, compared to unloaded counterparts. It was observed that org-clay stacks were dispersed into HDPE phase due to using of maleic anhydride grafted polyethylene as compatibilizer and HDPE/LCP/org-clay ternary nanocomposites exhibited intercalated microstructure. Solid-state uniaxial tensile creep behaviors of films were modeled with the Findley power-law and four-element Burger models. HDPE/LCP/org-clay (90/10/5) ternary nanocomposite film exhibited better gas barrier performance than HDPE by decreasing its permeability by 50%. POLYM. ENG. SCI., 59:1344-1353 2019. (c) 2019 Society of Plastics Engineers