THERMO-ACTIVE SHAPE MEMORY MULTI-LAYER PAPERBOARD PACKAGING

Abstract

A new shape memory paperboard laminated packaging concept is presented by introducing a polymeric shape memory layer within the multilayer structure. A shape memory polyethylene-like polymer, with low triggering temperature (Ttrans= 49.8ºC), was developed by crosslinking a polycyclooctene with a peroxide. Thermo-mechanical properties of the polymer were characterised, as well as shape memory properties. Once the shape memory material was developed and characterised, a series of different opportunities for shape memory packaging are presented, where the increase of temperature in food and/or packaging allows geometrical shape changes. Thus, from opening to collapsing movements of the carton-like packaging under heating operations are described. This thermoresponsive concept becomes into a new design tool to surprise the consumer. New interactive elements could emerge from packages which are able to open when suitable temperature is achieved and the food is ready. Equally, materials that change shape when exposed to high temperature could report about cooked dried food by thermo-responsive packaging. Finally, the presented concept is experimentally demonstrated by a laminate consisted of a thick paperboard layer, an adhesive polyvinyl alcohol film, a shape memory polyalkenamer film and a multilayered aluminium foil (polyethylene/aluminium/polyethylene), which was moulded as a self-opening package. Keywords: Shape memory polymers, Paperboard packaging, Self opening, Active packaging