Preparation of starch ethers using the dry process: carbamoylethyl and cyanoethyl starches and their copolymeric products with acrylamide/acrylonitrile mixture

Carbamoylethyl starch (CrES) and cyanoethyl starch (CES) were prepared by making use of the concept of the dry process under conditions which were developed to form the bases of environmentally sound (clean) technology. The obtained CrES and CES were saponified using alcoholic NaOH solution. The CrES and CES along with their saponified products were further modified by subjecting them to graft polymerization with Aam/AN mixture. Saponification of the so‐obtained grafted substances was also carried out. Presents the findings of these investigations which are explained in terms of structural changes in the starch, the ‐CN and CONH₂ groups, the Aam/AN polymeric graft and the site of attachment of the latter on the modified starch.