Amylose copolymers with

In all cases, the authors could successfully elongate the attached oligosaccharide structures using enzymatic polymerization, the product being comb-type block copolymers with amylose. 

This acceleration has been explained by the hydrogen-bonding interaction of the copolymer with the substrate. Poly(p-styrenesulfonic acid-co-acrylic acid) has been found to catalyze the hydrolysis of amylose and sucrose Partially o-benzyl-... 

Copolymers with Amylose The combination of oligo- or polysaccharides with non-natural polymeric structures opens up a novel class of materials. By varying the chain topology of the individual blocks as well as of the whole copolymer, the type of blocks, the composition etc. a complete set with tailor-made properties can be designed. 

Polyhydroxy- butyrate Polyhydroxybutyrate and its copolymer with polyhydroxyvalerate were blended with dextran or ainylose and compressed into disc shape. Dextran and ainylose were to enhance the enzyme degradability. Hydrolysis of polyhydroxybutyrate and its copol iTier. Also degradation by amylas< when blended sith amylose. Yasin and Tighe, 1993... 

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... 

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]. 

An interesting procedure has been proposed for the synthesis of amylose-b-PS block copolymers through the combination of anionic and enzymatic polymerization [131]. PS end-functionalized with primary amine or dimethylsilyl, -SiMe2H groups were prepared by anionic polymerization techniques, as shown in Scheme 56. The PS chains represented by the curved lines in Scheme 56 were further functionalized with maltoheptaose oligomer either through reductive amination (Scheme 57) or hydrosilyla-tion reactions (Scheme 58). In the first case sodium cyanoborohydride was used to couple the saccharide moiety with the PS primary amine group. 

Comb-type and linear block copolymer systems with enzymatically synthesized amylose have been reported and are outlined in the following section. 

The inhibition effect of poly (vinyl alcohol) on the amylose hydrolysis was investigated. Figure 7 shows Lineweaver-Burk plots of the amylose hydrolysis rates catalyzed by the random copolymer in the presence of poly (vinyl alcohol). The reaction rate is found to decrease with increasing the concentration of poly (vinyl alcohol), and all of the straight lines obtained in the plots cross with each other at a point on the ordinate. This is a feature of the competitive inhibition in the enzymatic reactions. In the present reaction system, however, it is inferred to suggest that the copolymer and poly (vinyl alcohol) molecules competitively absorb the substrate molecules. The elementary reaction can be described in the most simplified form as in Equation 3 where Z, SI, and Kj[ are inhibitor, nonproductive complex, and inhibitor constant, respectively. Then the reaction rate is expressed with Equation 4. 

These authors suspected that the slightly increased effidency of the copolymer is due to the cooperative contribution of hydrogen bonding and the electrostatic interaction. Subsequently, the same authors studied the hydrolysis of amylose and sucrose by some copolymers containing ilfonic acid and carboxylic add groups 25 (4i), Again, the polymer catalyst was not particularly effective compared with its small-molecule counterparts. 

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... 

Various linear block copolymers of the AB, ABA and ABC type with enzymatically polymerized amylose blocks were reported. Ziegast and Pfannemuller converted the hydroxyl end groups of poly(ethylene oxide) into amino groups via tosylation and further reaction with 2-aminoalkylthiolate. To the resulting mono- and di-amino functionalized poly(ethylene oxide) maltooligosaccharide lactones were attached and subsequently elongated to amylose via enzymatic polymerization. Pfannemuller et al. performed a very detailed study on the solution properties of the synthesized A-B-A triblock... 

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