Amylose grafted copolymers

Several groups have conducted graft copolymerizations on starch or its purified components, amylose and amylopectin. The syntheses are based on attack of the anhydroglucose unit of starch by cerium (+4) ion. The free radical produced from this attack is then immersed in a monomer solution polymerizable by free radical, chain polymerization and a graft copolymer is formed. A typical synthesis procedure (10,16) is as follows. 

Additional aging effects could be found for graft copolymers (starch-acrylamide copolymers [36], synthetic amylose [36],poly(acrylamide-co-methacryloxyethyl-N,N,N,-trimethylammoniumchloride) PAAm/M [30] and poly(acrylamide-co-sodium-2-sulfoethylmethacrylate) [37]. 

Styryl amylose amide (VAA) was prepared from maltopentose-substituted styrene (VM5A) by phosphorylase-catalyzed pol3unerization of glucose-1-phosphate (Glu-lP) (118) (Fig. 8). Subsequent radical copolymerization with acrylamide gave the corresponding graft copolymers.. 

In this chapter, an overview of hierarchically fabrication of eco-friendly supramolecular nanocomposites by means of inclusion complexation by amylose in the vine-twining polymerization was presented. The method was achieved by the phosphorylase-catalyzed enzymatic polymerization in the presence of the designed graft copolymers with guest polymeric chains. Inclusion complexation of amylose chains with guest chains in the intermolecular graft copolymers took place with the progress of the polymerization to construct the supramolecular nanocomposite... 

Alias, J. Silva, L Goni, 1 Gurruchaga, M. (2008). Hydrophobic amylose-based graft copolymers for controlled protein release. Carbohydrate Polymers, 74. 31 0. 

In the context of this chapter, the use of thermoplastic starch in blends with thermoplastic resins is of the main interest. As shown in Table 16.11, several blends have been developed, e.g., with vinyl alcohol copolymers (EVAl), polyolefins, aliphatic polyesters such as poly-e-caprolactone (PCL) and its copolymers, or polymers of glycols (e.g., 1,4-butanediol) with succinic, sebacic, adipic, azelaic, decanoic or brassihc acids, PCL + PVC. Compatibilization is possible by amylose/EVAl V-type complexes, starch grafted polyesters, chain extenders like diisocyanates, epoxies, etc. [Bastioli et al., 1992, 1993]. 

Another tjqie of comb like amylose hybrids synthesized via enzymatic grafting with phosphorylase is based on polysiloxane backbones. To achieve these structures double bonds were incorporated to the reducing end of oligosaccharides which were then attached to poIy(dimethylsiloxane-co-methylsiloxane) copolymers via hydrosililation or to silane monomers which were subsequently polymerized to polysiloxanes . Various mono-, d>-, tri and oligosaccharides were attached to siloxane backbones and their solution properties were studied with viscosimetry and static and dynamic light... 

Another class of rod-coil systems with helical rod segments is derived from amylose as one block. Most copolymer systems with amylose as one segment are based on an enzymatic grafting from polymerization with potato phosphorylase which was pioneered by Beate Pfannemiiller. Linear, star, and comblike polymers carrying amylose chains were reported by Pfannemiiller et al. [122-125]. Stadler and coworkers reported rod-coil systems composed of amylose blocks with polysiloxanes [126,127] (comblike structures) and polystyrene [128] (blocklike structures). Comblike structures based on polystyrene with amylose entities were synthesized by Kobayashi et al. [129]. 

In the compatibiUzation strategy mentioned above, 100% MA-grafted PLA was used to achieve the significantly increased ductility. In theory, one could expect that a much smaller concentration of MA-g-PLA is sufficient to react with the starch polymeric chains and to supply the complete interfacial coverage needed for compatibilization. The thermodynamic driving force for the reactive functional polymer (MA-g-PLA) to migrate to the blends interface will greatly influence the final copolymer (i.e. PLA-Amylose) distribution [2], and thus the efficiency of compatibilization. 

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