Mechanical, Chemical and Morphological Investigations on the Degradation of Low-Density Polyethylene Films Under Soil-Burial Conditions

Abstract

Commercial formulations of low-density polyethylene (LDPE) films were subjected to an outdoor soil burial test to investigate the environmental degradation under natural conditions. Samples periodically retrieved from soil were examined for changes in physical character, tensile properties, dielectric behavior, X-ray diffraction pattern and FTIR spectra. Irrespective of thickness and color, load-extension curves of all samples reflect complete or partial destruction of plastic and elastic regions after 15 to 17 months of soil exposure. IR spectra after 17 months revealed major absorption of the region from 1400–1800 cm−1, characteristic of carbonyl peak in polyethylene. Upon exposure, the power factor increased remarkably and fairly intense transition peaks were found in dielectric loss curves. XRD graphs reflected possible damage in the amorphous region of the polymer matrix. Disrupted holes under scanning electron microscope further revealed degradation of LDPE films under natural soil conditions.