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. Keywords: degradationLDPEsoil burial Acknowledgments The project received financial support from the Bangladesh Council of Scientific and Industrial Research (BCSIR) as a postgraduate fellowship to the first author. The authors would like to acknowledge the technical support received from the Department of Physics, University of Dhaka for the determination of mechanical and dielectric properties, and the Department of Botany, University of Dhaka for providing the experimental field.