Nanocomposites are polymers bonded with nanocrystals and they can be used to provide packaging materials to get extended shelf life. For example nanocomposites for use in plastic beer bottles can give the contents a six-month shelf- life. The material works by introducing nanocrystals into the plastic that essentially create a maze from which oxygen molecules find it difficult to escape. Nanocomposites also offer other benefits like lighter weight and better recyclability and significantly reduce transportation and production costs by reducing the amount of material used to package items. Materials that change properties depending on external or internal conditions have also been reported. For example, researchers hope to use the changing molecular composition of milk that is beginning to spoil to bring about a reaction with nanoparticles embedded in the packaging, causing the colour of the packaging to change. With enhanced properties materials carton that would tighten its existing molecular structure can be developed to prevent heat from affecting the content.