STARCH COPOLYMER

Type of water or solution Starch copolymers PVA PAAm... 

Graft copolymers of nylon, protein, cellulose, starch, copolymers, or vinyl alcohol have been prepared by the reaction of ethylene oxide with these polymers. Graft copolymers are also produced when styrene is polymerized by Lewis acids in the presence of poly-p-methoxystyrene. The Merrifield synthesis of polypeptides is also based on graft copolymers formed from chloromethaylated PS. Thus, the variety of graft copolymers is great. 

Geresh, S., Gdalevsky, G. Y, Gilboa, T, Voorspoels, J., Remon, J. R, Kost, J. (2004). Bioadhesive grafted starch copolymers as platforms for peroral drug delivery a study of theophylline release. J. Contr. Rel, 94(2-3), 391-399. 

Substitution of cornflour for cornstarch yielded more flexible copolymers, with lower tensile strengths but greater elongation and tear strength, compared to starch copolymers.117 Comflour-g-PMA could be extruded into blown films, in contrast with starch-g-PMA prepared from granular starch. The effects of sequential CAN addition were similar to those observed for starch-g-PMA.115... 

While starch copolymers are typically prepared by batch polymerization methods, reactive extrusion of starch has been studied. Mixtures of starch, polystyrene, styrene, sodium hydrogen carbonate, citric acid and water were extruded at temperatures between 100°C and 200°C.118 It was reported that expanded graft copolymers... 

Reduction of acetals with NaBH4 was reported,1369 but no applications of the products were given. Crosslinking of starch acetals with epichlorohydrin and similar compounds was also described.1370 A urea-formaldehyde-starch copolymer reacted with hydrogen peroxide and Cu(II) catalysts, thereby producing a starch solution with improved stability of viscosity.1371... 

Graft copolymers of starch with acrylonitrile and 2-acrylamido-2-methylpropanesulfonic acid, after saponification, were claimed to be good sorbents.3092 A composite of saponified acrylonitrile-starch-copolymer with vinyl formal polymers showed very good salt-rejection characteristics and served as membranes.3093 The same material prepared with poly(vinyl chloride) has been used in gaskets for concrete pipes.3057 Saponified acrylonitrile-starch graft copolymers blended with C12-C16 alcohols provided excellent water-retention characteristics.3094... 

Geresh, S. Gilboa, Y. Peisahov-Korol, J. Gdalevsky, G. Voorspoels, J. Remon, J.R Kost, G. Preparation and characterization of bioadhesive grafted starch copolymers as platforms for controlled drug delivery. J. Appl. Polym. Sci. 2002, 86 (5), 1157-1162. 

Specialty chemicals Bacitracin, detergents, EDTA sodium salts, fertilizer plant wastewater, latex starch copolymer, neat soap, organic pigments. ... 

A host of such blends including starch + cellulose acetate, PCL, starch + PP and starch + copolymers are commercially available. 

FIGURE 21 Commercial bio-based polymers (a) starch copolymer based biodegradable carry bag, (b) 50-50 film blend of poly lactic acid and petroleum-based materials for packaging cheese snacks, (c) packaging blister made from cellulose acetate, (d) biodegradable bottle on sale in Britain, (e) PLA yoghurt cup, and (f) 100% degradable sandwich box. 

Figure 4.1 X-ray diffractograms of methacrylate-starch copolymer and native starch showing the amorphization of the polysaccharide.

Figure 4.2 Microphotographs corresponding to tapioca starch and methacrylate-starch copolymer showing the increased size of particles.

M. Casas, C. Ferrero and M.-R. Jimenez-Castellanos, Graft tapioca starch copolymers as novel excipients for controlled-release matrix tablets, Carbohydr.Polym., 80 (1) 71-77, 2010. 

In the case of starch polymer pellets, energy requirements are mostly 25-75% below those for polyethylene (PE) and greenhouse gas emissions are 20-80% lower. These ranges originate from the comparison of different starch/copolymer blends, different waste treatments, and different polyolefin materials used as reference. Regarding the latter, APME data for LLDPE (72.3 MJ/kg) and LDPE (80.6 MJ/kg) were assumed, which are lower than the value according to Carbotech (91.7 MJ/kg, see Table 4). The lower APME values serve also as reference for the comparison with the other biopolymers (see below). 

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