**9. Conclusion**

Native starch has complex supra-molecular structures that must be disrupted and dissociated to form amorphous thermoplastic starch. Water, other plasticisers, temperature and shear are important in gelatinising starch to form TPS. TPS is processed using extrusion then formed using injection moulding or thermoforming, the same as synthetic thermoplastics. TPS can be combined with other polymers in blends and fillers to form composites. Problems with TPS are water sorption and retrogradation, causing properties to change over time and under prevailing ambient conditions. There are many varieties of starch with differing composition, processing behaviour and properties. This makes development of TPS materials highly specific to particular starch types during development and application. Starch has interesting theoretical properties as a polymer. There is not theoretical distinction between synthetic and natural polymers, except for the complex intermolecular interactions resulting from polarity and hydrogen bond formation and the multileveled hierarchy of ordered structures that form. Starch presents many characteristics, found in synthetic polymers, in the one polymer: linear chains with a single repeat unit, branching, hydrogen bonding, crystallinity, gelatinisation, melting and glass transition phenomena, liquid crystalline characteristics, retrogradation, upper critical solution temperature behaviour, solubility, gelation all combined to form the technology of thermoplastic starch production.
