Synergistic effect of combining UV-sunlight-soil burial treatment on the biodegradation rate of LDPE/starch blends

The present work has focused on the possibility of accelerating the biodegradation process of low-density polyethylene (LDPE) by mixing it with starch and exposing the obtained blend to the effect of UV radiation and soil burial treatments. Comparable studies between the properties of untreated LDPE/starch blends and those exposed to UV irradiation and/or soil burial treatment were investigated. In reference to the mechanical properties of untreated blends. The tensile strength of the blends exposed to UV irradiation-soil burial treatments was reduced by 20-66%, meanwhile, the tensile strength of the blends exposed only to soil burial treatment reduced by 10-26% from the initial value according to the starch content in the blend. The changes in the thermal, structural, and morphological properties of the blends due to the photo-irradiation and/or microbial treatments were determined using differential scanning calorimetry (DSC), transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The obtained results showed that there is a synergistic effect on the LDPE/starch biodegradation process when the blends exposed to UV-sunlight and followed by soil buried treatment. This means that photo-radiation induced oxidation reaction enhanced and accelerated the biodegradability rate of LDPE/starch blends by creating oxidized LDPE/starch that is more susceptible to biotic reactions. The results suggested that it is possible to replace non-degradable polyethylene polymer by biodegradable one for controlling the lifetime of its waste. (C) 2004 Elsevier B.V. All rights reserved.