Post-consumer recycling of Tetra Pak®: Starting a “new life” as filler in sustainable polyurethane foams

Tetra Pak® is a laminated packaging consisting in cardboard, aluminum and LDPE layers, used to preserve several food products and beverages. Recycling of such material is not trivial; usually packages end up in the landfill. In this study, Tetra Pak® scraps were used as reinforcing filler for sustainable composite polyurethane (PU) foams, without components separation. Foams were prepared through polyaddition reaction between di-isocyanate source and biobased polyols, in presence of suitable additives and blowing agents, and by loading Tetra Pak® at 5 wt% and 20 wt%, respectively. The effect of filler size, shape and concentration on thermal, morphological and mechanical characteristics of the foams was investigated. The intercalation of Tetra Pak® corresponded to compressive stress (3 times more) and the flexural stress (50% more) increases with respect to the unloaded foam. The so-obtained foams can be used in food packaging (as containers) and in other applications.