Many food products require cold chain transportation to ensure food safety and quality. Refrigerated temperatures slow down microbiological decay of food products and improve shelf life. In the case of a cold chain failure, temperature fluctuations may lead to deterioration of the food and shorter shelf life. Similarly for the transportation of frozen food products, it is crucial that the temperature of the food product stays below minus 18°C so that thawing does not occur. Food packaging materials that present thermal buffering capacity around 4°C can keep food product cold for longer.
PCMs are substances that undergo a melting/crystallization phase transition and absorb latent heat at constant temperature. PCMs have been widely investigated as energy storage materials and utilized in a variety of application areas. They have also been studied as materials with thermal buffering capacity for food packaging applications. The limited thermal buffering capacities of standard packaging materials such as plastic, cardboard and wood can be increased through incorporation of PCMs resulting in packaging materials that can prevent temperature fluctuations of packaged food products. PCMs that are applicable for latent heat storage around refrigerated temperatures are liquids at room temperature, which makes them difficult to incorporate into food packaging materials. Encapsulation of PCMs has been a viable method that prevents the leakage of PCMs and their environmental reactivity. There have been limited examples of encapsulated PCMs which have been incorporated into food packaging materials that are able to control temperature fluctuations. A paraffin based PCM has been encapsulated by a biopolymeric matrix through electrospinning and resulting electrospun PCM-containing matrix was claimed to have a potential as frozen food packaging; the effect of food packaging on temperature fluctuations was not demonstrated.
The technology is about packaging films that can reduce temperature fluctuations along the cold chain where the packaged food products are cold even when the outside temperature is raised above refrigerated temperatures.
The films are nanocomposites of polymers and halloysite nanotubes impregnated with phase change materials. More than one type of PCM that present melting at consecutive temperatures 0-15°C can be incorporated into the packaging films which results in packaging films that present thermal buffering in a wider range of temperatures and keep packaged food product cold for longer time. Halloysite nanotubes impregnated with different PCMs are mixed in equal proportions and incorporated into thermoplastic polymers through melt compounding and flexible packaging films with thermal buffering properties are prepared. As the design of the nanocomposite packaging film allows incorporation of more than one PCM with different melting temperatures, the temperature range at which the PCM melting occurs is larger, therefore, the packaging film presents thermal buffering at a wider temperature range. The proposed technology will be the first example of flexible packaging films with cold storage capacity and can be applied in packaging of frozen food or for cold storage of perishable products. The films can be used by wrapping food products or as liners on top of the food, they can keep the food frozen for longer times than standard films when the outside temperature rises without requiring extra insulation.
These nanocomposite packaging films can be utilized for transportation of temperature-sensitive products in different industries.
The university is seeking partnerships with companies have proven experience and knowledge to manufacture the raw material of nanocomposite flexible packaging films or apply them for their packages by using extrusion under license agreement, manufacturing or a commercial agreement with technical assistance.