V. Arabli, A. Aghili
Islamic Azad University, Shiraz branch,
Iran, Islamic Republic of
Keywords: LDPE-LLDPE, EVA, nanoclay, mechanical properties, optical properties, thermal properties
Summary:
This study examines the impact of incorporating Ethylene vinyl acetate (EVA) and nanoclay on the thermal and optical characteristics of traditional LDPE-LLDPE packaging films. A specific film grade of LDPE with optimized optical properties, including favorable haze and micro-gloss, was used. Morphological examinations, including SEM, TEM, and XRD, were conducted, along with the analysis of mechanical characteristics such as tensile properties and tear resistance. The differential scanning calorimetry (DSC) results indicated that the nanocomposites, comprising 3 phr clay nanoparticles and a matrix with 50% EVA, exhibited optimum mechanical, thermal, and optical properties. The XRD patterns of the nanocomposites also demonstrated the achievement of an exfoliated/intercalated structure. According to the XRD patterns, the degree of exfoliation is higher in N1, which contains 1 phr of clay nanoparticles, whereas the N3 nanocomposite, containing 3 phr of clay nanoparticles, exhibits superior mechanical properties. Despite this, N3 has a lower degree of exfoliation compared to N1. The XRD findings were corroborated by TEM images. The scanning electron micrographs indicate that the morphology of the blends containing 40% EVA and higher shifted from a Matrix-Disperse structure to a Co-Continuous structure, enhancing the uniformity and synergistic effect of the blend. The results of the mechanical tests clearly demonstrate this. The addition of EVA has enhanced the toughness properties of the blend (increasing elongation at break, impact resistance, and tear resistance), while the addition of clay nanoparticles has increased the stiffness properties (modulus and tensile strength) of the blends. The inclusion of EVA in the blend improved the clarity and gloss of the films. Additionally, the addition of clay nanoparticles somewhat enhanced the crystallization and thermal properties of the blends.