Starch blend polymers agricultural applications

Otey et al. [61, 68-71] also described blends of starch with synthetic polymers, in which gelatinized starch was used instead of starch granules. The initial films, composed of 90 per cent of starch blended with poly(ethylene-co-acrylic acid) (EAA), were obtained by casting from aqueous dispersions or by dry milling in a rubber mill, followed by a hot roll treatment, but only the cast films attained acceptable characteristics [71]. These materials were intended for application as mulch films for agriculture. 

Polylactide has high potential in agricultural applications such as mulch films either in pure form or blended with other polymers such as thermoplastic starch. In addition, polylactide is used in compostable yard bags and dog poop bags. Lactic acid based hot-melt adhesives have also been developed (90). Foamed PLA could be used as structural protective foams, loose-fill packaging and insulation material as an alternative for expanded polystyrene (EPS). While packaging is currently the high volume application... 

Another way of generating biopolymers is the fermentation of starch, sugar and other commodities by various microorganisms. Typical examples are poly(hydroxyalkanoates) (especially poly(hydroxybuty-rate) (PHB)) and poly(lactic acid) (PLA). Due to the chirality of lactic acid (D- L-form), two distinct forms of poly(lactic acid) exist (poly(L-lactic acid) and poly(D-lactic acid)). PLA is used, e.g. in biomedical application (sutures, stents, drug-delivery, preparation of bioplastic), in agriculture (mulch-film), packaging, and in blends with synthetic polymers. 

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