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Alkylated starches, properties

Starch is an abundant, inexpensive polysaccharide that is readily available from staple crops such as com or maize and is thus is mostly important as food. Industrially, starch is also widely used in papermaking, the production of adhesives or as additives in plastics. For a number of these applications, it is desirable to chemically modify the starch to increase its hydrophobicity. Starch modification can thus prevent retrodegradation improve gel texture, clarity and sheen improve film formation and stabilize emulsions [108], This may, for example, be achieved by partial acetylation, alkyl siliconation or esterification however, these methods typically require environmentally unfriendly stoichiometric reagents and produce waste. Catalytic modification, such as the palladium-catalyzed telomerization (Scheme 18), of starch may provide a green atom-efficient way for creating chemically modified starches. The physicochemical properties of thus modified starches are discussed by Bouquillon et al. [22]. [Pg.84]

Carbohydrate hydroxyl groups are alkylated in three contexts analysis of polysaccharide sequences, dealt with in Section 4.2.1 protection of OH groups during synthetic transformations, which requires the alkyl residues to be removable and the modification of cheap polysaccharides, such as starch and cellulose, for more desirable properties. [Pg.516]

A present-day boom of interest to alkyl polyglycosides APG, known however for hundred years, is caused by several reasons finding of technologically acceptable and cost-effective ways of their synthesis, availability of renewable resources (starch, treacle and alcohols of natural origin), environmental compatibility, high surface activity, excellent usage and dermatological properties [4-6 24]. [Pg.7]

In practice, the techniques of blending, compositing and nano-reinforcement are often used together. Thermoplastic starch/poly(vinyl alcohol) (PVOH)/clay nanocomposites exhibited the intercalated and exfoliated structures [260]. Mont-morillonite (MMT) with three types of cation or modifier (Na", alkyl ammonium ion, and citric acid) was examined. The prepared nanocomposites with modified montmorillonite indicated a mechanical improvement in the properties, in comparison with pristine MMT. [Pg.147]

Succinic anhydride reacts directly with starch to form a half-ester called starch succinate. Starch can also react with alkyl or alkenyl derivatives of succinic anhydride to form the corresponding succinates, among which one of the most used is starch sodium octenylsuccinate. Due to the presence of hydrophobic and hydrophilic groups, this product has interfacial activity and emulsif5ung properties. Alkenylsuccinates are used in food, pharmaceutical and industrial applications [39]. [Pg.501]


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See also in sourсe #XX -- [ Pg.214 ]




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Starch properties

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