Advances in Polymer Technology, Vol.22, No.2, 112-119, 2003
Preparation and properties of heat-shrinkable cross-linked low-density polyethylene
In this work, heat-shrinkable characteristics of a polyethylene compound were obtained by blending mixtures of low-density polyethylene with varying amount of peroxide. These were then extruded and molded to the required shape and then cross-linked by chemical means, followed by heating and stretching and then cooled to "freeze-in" the oriented polymer structure (elastic memory). A decrease in the melting point and heat of fusion (DeltaH(f)), as determined from the DSC melting enthalpies, was observed with an increase in the dicumyl peroxide (DCP) concentration. Tests on the heat shrinkablity of the samples showed that the stretching temperature has a large effect on the shrinkage temperature. The results showed that by increasing the peroxide content, the shrinkage temperature was decreased. The elongation at break decreased with an increase in the DCP concentration. Increasing the temperature in lightly cross-linked samples (low percent DCP) resulted in a reduction in the elongation at break. Increasing the cross-linking density (DCP content) gave an opposite effect. (C) 2003 Wiley Periodicals, Inc.