Mechanical, Rheological and Thermal Properties of Polyethylene (PE)/Clay Nanocomposite for Rotomolded Containers

Date
2014-09-30
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Abstract
Polyethylene (PE) is widely used to make bulk containers via rotational molding process. Adding 2 wt % and 4 wt % organo-modified clay improved the thermal, barrier and mechanical properties of PE. Clay layers create a tortuous path against the permeant, yielding better barrier properties. Due to the non-polar hydrophobic nature of PE and polar hydrophilic structure of clay minerals, a compatibilizer (PE-g-Maleic Anhydride) was required to enhance the dispersion level of clay in the matrix. In this study High Density Polyethylene (HDPE) and Linear Low Density Polyethylene (LLDPE) layered silicate nanocomposites were melt-compounded with two concentrations of organo-modified clay (2 and 4 weight %). The interaction between nanoclay, compatibilizer and rotomolding grade of PE were examined using X-ray diffraction (XRD), transmission electron microscopy (TEM), mechanical and rheological tests. The XRD results revealed an enhanced basal spacing of layered silicates within both LLDPE nanocomposites at low nanoclay loadings, in agreement with the TEM observations; TEM images showed a uniformly dispersed layered silicates. Through thermal and rheological characterization techniques, the results illustrated that the thermal resistance, elastic and viscous modulus of nanocomposites improved significantly with incorporation of layered silicates. Analyzing all the data showed enhanced properties of LLDPE nanocomposites, which can be attributed to a strong interfacial interaction between the compatibilizer with LLDPE backbone and LLDPE matrices compared with HDPE matrices. The influence of in-house organo-modification of layered silicates on the properties of nanocomposites was compared to that of nanocomposites prepared with commercially available nanoclay (Cloisite 20A). LLDPE nanocomposites prepared by the in-house organo-modified clay showed better mechanical properties, elastic and viscous modulus due to good dispersion of layered silicates as determined by the XRD patterns. In addition, the complex viscosity measurements and sintering experiments allowed us to obtain a general understanding of the behavior of pure PE and nanocomposites at low shear rate processing conditions. The results showed only a modest decrease in sintering rate of LLDPE (8555)/clay nanocomposites which is ascribed to an enhanced miscibility and interaction of the nanocomposite components. Thus, processing times for LLDPE/clay nanocomposites should be comparable to pure LLDPE.
Description
Keywords
Chemistry--Polymer, Engineering--Chemical
Citation
Jamshidi, S. (2014). Mechanical, Rheological and Thermal Properties of Polyethylene (PE)/Clay Nanocomposite for Rotomolded Containers (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/26860