Investigation of thermal and physical properties of crosslinked LLDPE/w ax blends in the presence of dibenzoyl peroxide
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Date
2002-01
Authors
Hlangothi, Shanganyane Perseverance
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Publisher
University of the Free State
Abstract
In this work, the thermal and mechanical properties of uncross-linked and cross-linked LLDPE/wax blends were investigated. The mechanically mixed samples were melt-pressed into sheets, from which the analyses were done. The thermal analyses were determined using DSC, TGA, and melt flow extrusion plastometer. It was found that wax is apparently miscible with LLDPE in both the crystalline and molten states. It was also found that changes in wax and the cross-linking agent contents result in changes in (i) the degree of crystallinity of the blends, (ii) melting and cooling temperatures of the blends, and (iii) the thermal stability of the blends. The cross-linking of the blends induced by DBP significantly affects the mechanical properties. It was found that the ultimate properties of LLDPE/wax blends deteriorated in the presence of wax. Stress at break increased as a function of DBP content, whereas elongation at break decreased. The yield point properties also resulted in interesting changes as the concentrations of wax and DBP were varied. Elongation at yield increased with increasing wax content and decreased with increasing DBP content. It was further found that higher concentrations of wax improved Young's modulus of blends, while higher cross-linking efficiency showed the opposite.
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Keywords
Dissertation (M.Sc. (Chemistry))--University of the Free State (Qwaqwa Campus), 2002, Waxes -- Analysis