Characterization and characteristics of degradable polymer sacks

This paper reviews the categories and characteristics of degradable polymers used to manufacture sacks for the collection and subsequent treatment of organic wastes from householders. The characteristics of polyethylene (PE) and starch-based sacks were examined using a number of different methods, including scanning electron microscopy (SEM), chemical analysis and mechanical strength testing of the sacks during their use. The analyses revealed that the characteristics of the PE and starch-based sacks were very different. Photomicrographs indicated that the surface of the PE sack was much smoother than the surface of the starch-based sacks. Polyethylene sacks exhibited a greater mechanical strength, both in the unused state and over time during householder use. The severe loss of mechanical strength during use of the starch-based sacks indicated that only thicker gauge sacks were suitable for the fortnightly kerbside collection of biodegradable municipal waste (BMW). Chemical analysis of two different PE sacks indicated that transition metals and other elements were commonly incorporated into the PE structure in order to facilitate increased polymer degradation