Polyethylene and hydrolyzed collagen blend films produced by blown extrusion

The use of plastics packaging is widespread. For this reason, there is a growing interest in develop of novel materials by blends of synthetic and natural polymers which can help to reduce the environmental impact of plastics. Hydrolyzed collagen (HC) from leather industry is an inexpensive natural biopolymer and it is a promising material for blending with synthetic polymers (e.g., polyethylene) to produce different types of item (it is no food competition, low cost, and biodegradable-compostable). Due to the wide difference in polarity, the natural polymer does not disperse easily in nonpolar thermoplastics, therefore the structural differences between polyethylene and collagen hydrolizate make them incompatible. Thus, in this work compatibilizing agents as maleic anhydride functionalized ethylene elastomers have been used. The content of HC in polyethylene matrix varied between 10 and 50 wt%. Transparent, cohesive and flexible films, having an average thickness of 60 μm, were obtained by using the film blowing technique. Film blowing is a shaping technique used extensively to produce most plastics films and bags for packaging applications. The extruded films were characterized through mechanical testing, scanning electron microscopy, and thermal analysis. The films containing up to 20 % of collagen hydrolizate, in the presence of compatibilizing agents, are characterized by satisfactory thermal-mechanical properties. Thus HC/PE blends appear as promising candidate for the production of innovative material suitable for production of thermoplastic items for applications in packaging and agricultural segments.