Starch Destructurisation in the Presence of Synthetic Polymers

Starch can undergo a thermoplastic transformation up to destructurisation in the presence of different synthetic polymers to satisfy a broad spectrum of market needs. Destructurised starch composites can reach starch contents higher than 50%. 

With some of these polymers, the complexation of a single amylose helix with the polymer backbone can occur, which gives rise to supramolecular structures characterised by V-type crystallinity. This sort of modified amylose crystallinity is the same as mentioned in Section 8.4.4 and has been widely studied with small molecules such as alcohols, glycerol, dimethylsulfoxide, fatty acids or iodine [66]. 

The complexation of starch by macromolecules can give rise to even more stable complexes which play an important role on the final properties of the starch-based polymer. Unlike amylose, the majority of amylopectin does not interact with the complexing agent and remains in its amorphous state. In the following paragraphs, a summary of the state of the art related to starch destructurisation with synthetic polymers will be made. 

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Usually, starch destructurisation in the presence of synthetic polymers, gives rise to Vh and Eh structures (always a V-type one). The latter, in particular, is obtained with high mechanical stress and low moisture content [130]. 

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