Monitoring the degradation of partly
decomposable plastic foils

Abstract

For one year, we have monitored the behavior of the following foils in the soil: I. Medium density polyethylene (MDPE), II. MDPE + thermoplastic starch and pro-oxidative additives, III. MDPE + pro-oxidative additives, and IV. Commercially available bio-degradable BASF foil containing PLA.  The plastic bags were filled with soil and placed in a beaker containing soil, thus the plastic bags were surrounded by soil. Measuring electrodes were put into the soil that was in the plastic bag, and into the soil that surrounded the plastic bag. Conductivity and capacity of the samples were measured weekly,  changes in film thickness, molecular mass, mechanical, rheological and morphological properties, were investigated monthly.

Based on the capacity and conductivity results among the MDPE foils the thermoplastic starch containing plastic decayed the most. The foils that contained pro-oxydative additives slightly changed after the experiment. The smallest change showed the pure polyethylene foil. The BASF foil decayed the most in the soil.

Keywords: polyethylene foil, degradation in soil, capacity, conductivity, tensile strength, elongation at break

Acknowledgement