Study of physical and mechanical properties of partially biodegradable LDPE polymeric films and their application for printing and packaging

Abstract

Potato starch, glycerine, itaconic acid and molasses of different physical state (dry and liquid) were used for manufacturing partially biodegradable low density polyethylene (LDPE) films. The mechanical, physical properties of new polymeric films with different physical state were investigated using these test methods: scanning electron microscopy, FTIR spectroscopy, thermogravimetric analysis, tensile testing, heat seal testing and printability testing. Investigated film properties were determined and compared with the properties of the pure LDPE film. It was determined that thermal stability did not changed significantly with the addition of biodegradable additives. The tensile strength and elongation of LDPE films containing potato starch, glycerine and itaconic acid were about 50% lower than pure LDPE film but of the film containing dry molasses and glycerine - was only 25% lower. The heat seal strength of film containing dry molasses was the closest to pure LDPE film at 115 °C. The other tested films required a higher temperature range to form a seal of sufficient strength. The SEM microphotographs have shown the particles of biodegradable additives randomly oriented on the surfaces of some LDPE films, thus, the values of optical density of only one LDPE film containing potato starch and glycerine were the closest to pure LDPE film. LDPE with molasses has been found to be the most suitable film for printing and packaging processes.