Behavior of polyethylene films in soil

Abstract

A true-to life experiment on the behaviour of polyethylene films in soil was carried out. Commercial middle density polyethylene (MDPE) film, MDPE films containing pro-oxidative additives and thermoplastic starch and a commercially available biodegradable film (Ecovio, BASF) have been buried in soil and monitored monthly for one year. Bags made out of the films were filled with and surrounded with brown forest soil and electrodes were put into the soil inside the bag and into the soil surrounding the bag. The soil served as capacitor. Degradation could be monitored weekly by measuring the capacity and conductivity of the soil without removing the bags from it. Visual, mechanical (Instron), structural (FTIR, ESR) and morphological (POM, SEM) changes in the films and the change in molecular mass were tested monthly. The polyethylene films suffered only some physical degradation and not biodegradation. Our life-like experiments suggest that biopacking will be the future of plastics waste disposal.