Chemical Modification of Starch via Reaction with Acrylamide

Abstract

Reaction of starch with acrylamide was carried out under different conditions including reaction medium, catalyst, acrylamide concentration, reaction time and temperature as well as liquor ratio. Organic solvents, namely, isopropyl alcohol, dimethylformamide and cyclohexane alone and in admixture with water at different ratios were used as reaction medium. Catalysts used include sodium hydroxide, trisodium phosphate, sodium carbonate, sodium benzoate, sodium acetate and sodium formate. Acrylamide concentration ranged from 25% to 200%, based on weight of starch. The reaction was studied over a wide range of temperature and duration. Results obtained showed that the extent of reaction of starch with acrylamide is governed by each of these factors. Furthermore, this reaction yields mixed starch ethers, namely carbamoylethyl starch and carboxyethyl starch. Solubility, viscosity and moisture content of these starch ethers are determined by the sum of the amide and carboxyl contents.

Synthesis, characterization and swelling behaviour of superabsorbent polymers from cassava starch‐graft‐poly(acrylamide)

“…The increase in absorbency of SAP with increase in concentration of the monomer used could be explained by the fact that grafting efficiency increases with increasing monomer‐starch ratio and more monomers can react at the grafting sites in the starch. Since starch hydroxyls are immobile, the reaction with acrylamide depends upon the availability of acrylamide molecules in the proximity of the hydroxyl groups in starch 20. An increased acrylamide in the blend renders the network more hydrophilic, which in turn increases the absorbency 9.…”

Some Studies on Starch Carbamate

“…It is known that introduction of amide groups on the starch backbone leads to increasing its solubility [13,17]. Hence on re- acting urea with starch to form starch carbamate its solubility increases with increasing the reaction extent up to the obtained maximum value.…”

Effect of graft‐copolymerization with poly(acrylamide) on rheological and thermal properties of cassava starch

“…There are many reports on the synthesis and characterization of starch graft‐copolymers using various free radical initiation systems. However, most of them are confined to cereal and potato starches2–5 and a few are on cassava starch 6, 7. Graft copolymerization is reported to alter the thermal stability of starch 1, 5–9.…”