RELATIONSHIPS BETWEEN PROCESSING-STRUCTURE-MIGRATION PROPERTIES FOR RECYCLED POLYPROPYLENE IN FOOD-PACKAGING

In this work the relationships between processing, structure and migra tion properties of recycled polypropylene (PP) were analysed in relati on to the possible use of recycled PP in food packaging applications. PP containers used in food packaging were contaminated with food and t hen washed reduced into a processable size, dried and reprocessed by i njection moulding. Gel Permeation Chromatography (GPC) analysis, mecha nical, and total migration tests were performed on injection moulded s amples to verify the effect of the recycling process on the structure and properties of PP. In order to evaluate the effect of the molecular weight on the properties of the recycled polymer, the study was condu cted on containers produced by injection moulding made from a low mole cular weight (LMW) PP and on containers produced by thermoforming made from a high molecular weight (HMW) PP.