Preparation and characterization of modified and functional starch (hexadecyl corboxymethyl starch) ether using reactive extrusion

Water‐soluble carboxymethyl starch (CMS) derivatives with both hydrophobic and hydrophilic characteristics were synthesized by reacting CMS with cetyl bromide (CB) using an extrusion process in an alkaline etherification reaction. A series of hexadecyl carboxymethyl starch ethers (HCSE‐ex) with degrees of substitution ranging from 0.0257 to 0.0701 were characterized under different reaction conditions based on their physical (morphology and viscosity) and thermal properties. FTIR, SEM, TGA, and X‐ray results confirmed that etherification produced high reaction efficiencies, and the derivatives exhibited excellent emulsification efficiency. The application of extrusion as an energy source resulted in a much reduced etherification time compared with traditional methods, down from several hours to several seconds, indicating the high potential of extrusion to improve and increase the efficiency of technological polysaccharide etherification.