New Starch Hybrids via Etherification of Poly (Acrylamide)-Starch Copolymers with Acrylamide | ||||
| Egyptian Journal of Chemistry | ||||
| Article 1, Volume 56, Issue 4, August 2013, Page 255-270 PDF (534.52 K) | ||||
| DOI: 10.21608/ejchem.2013.1112 | ||||
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| Abstract | ||||
| NOVEL starch hybrids containing acrylamide (Aam) moieties in …….monomeric (i.e carbamoylethyl groups) and polymeric (poly acrylamide) forms were synthesized. Thus, starch was first polymerized with acrylamide to yield poly (Am)-starch composite and poly (Aam)-starch graft copolymer which represent the total polymerization products before and after removal of the homopolymer, respectively. The composite and the copolymer were then carbamoyethylated via reaction with Aam. Beside the carbamoylethyl groups, carboxyethyl groups were inevitably formed during carbamoylethylation. This and the onset of such modification on the rhelogical properties of the so synthesized starch hybrids signify the following. a) The extents of carbamoylethylation of the composite and the copolymer were much lower than native starch; b) The magnitude of poly(Am) content in the form of graft or homopolymer adversely affects the carbamoylethylation reaction; c) before carbamoylethylation, the composite, the copolymer and native starch exhibited non-Newtonian thixotropic behavior, d); after carbamoylethylation the etherified products were characterized by pseudoplastic behavior. The apparent viscosity of starch, starch composite and starch copolymer decreased significantly after carbamoylethylation but with the certainty that the apparent viscosity increased by increasing the carbamoylethyl and carboxyethyl groups in these starch hybrids. | ||||
| Keywords | ||||
| Starch%; copolymer; acrylamide; Etherification and Composite | ||||
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