| Résumé | In order to develop correlations between the properties and microstructural characteristics of polyethylene blown films, three polymers were evaluated in this study: low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and high density polyethylene (HDPE). Series of blown films were produced at different process conditions. Morphological characteristics of the films were analyzed using X-ray diffraction, scanning electron microscopy (SEM), atomic force microscopy (AFM), FTIR, and birefrigence measurements. Herman's orientation factors of the films were determined via both wide angle X-ray diffraction (WAXD) pole figures and infrared dichroism. Differential scanning calorimetry and WAXD were used to determine the degree of crystallinity and crystal dimensions. Finally, key mechanical properties including Elmendorf tear, dart impact, tensile properties in both MD and TD and optical properties such as haze and clarity have been measured. By using the statistical design of experiments and multivariate modeling, these properties are correlated to the microstructural parameters including the degree of crystallinity, lamellar thickness, Herman's orientation factors, and roughness. |
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