Plasticised natural polymer-based

Casein is a natural polymer extracted from skim milk proteins. It represents a small but important percentage of all the natural polymers used for the manufacturing of water-based adhesives. The casein formulations are highly soluble in alkaline solutions and in water. Casein polymers (modified or not) are mainly used in the manufacture of adhesives and the packaging industry for breweries, wineries and refrigerated products. Casein is also a binder for paints and an additive for adhesives formulations. It can also be used as a plasticiser for concrete. Beyer Richard (2002) demonstrated die feasibility of preparing casein polymer to make edible films and for food products containing this polymer. 

In nature, starch is based on crystalline beads of about 15-100 microns in diameter. Crystalline starch beads in plastics can be used as fillers or can be transformed into thermoplastic starch, which can either be processed alone or in combination with specific synthetic polymers. To make starch thermoplastic, its crystalline structure has to be destroyed by pressure, heat, mechanical work or use of plasticisers. Three main families of starch polymer can be used pure starch, modified starch and fermented starch polymers. 

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