Preparation method of salt-resistant carboxymethyl starch

Abstract

The invention relates to a preparation method of salt-resistant carboxymethyl starch. A mixed solvent of ethanol and isopropyl alcohol serves as a reaction medium, and multi-step modification of cassava starch is performed in slurry taking the mixed solvent as a medium. The method comprises the following specific steps: swelling the starch to prepare starch milk; adding a surfactant and performing modification such as alkalization and etherification by an 'acid pretreatment process'; and adding a crosslinking agent for a micro-crosslinking reaction. In the method provided by the invention, the surfactant is added as a penetrant, the reagent molecules are promoted to penetrate and spread into the starch particles, and the alkalization efficiency and etherification efficiency are improved; the generation of side reactions can be reduced by adding an etherifying agent before an alkalizer, thus the alkalization and etherification are carried out at the same time, and more thorough etherification reaction is guaranteed; finally, the starch is subjected to micro-crosslinking so as to improve the structure viscosity and enhance the salt resistance; the product viscosity 4% exceeds 40,000, the substitution degree is over 1.0, the salt-viscosity ratio goes beyond 0.5, and the product can be applied to multiple technical fields instead of CMC.

Description

technical field [0001] The invention belongs to the field of chemical modification of natural polymer materials, and in particular relates to a method for preparing salt-resistant carboxymethyl starch by using cassava starch as a raw material and performing multiple denaturation by a slurry method. Background technique [0002] Carboxymethyl starch is a starch derivative obtained by bimolecular nucleophilic substitution reaction between starch and chloroacetic acid under alkaline conditions, commonly known as CMS. It is a white or slightly yellow powder, odorless and non-toxic, soluble in water to form a thick colloidal solution, with good thickening, cohesiveness, dispersibility, emulsification, water retention, film-forming properties, etc. Its structure and properties are similar to carboxymethyl cellulose, and it can replace carboxymethyl cellulose in many occasions and be used in food, medicine, daily chemical, textile, papermaking, petroleum, agricultural production an...

AI Technical Summary

Problems solved by technology

These methods have their own advantages and disadvantages: the dry method is that the starch and the reagent react in the solid phase, the heating is uneven and unstable, and it is difficult for reagents such as sodium hydroxide and chloroacetic acid to penetrate into the interior of the starch granules, so the degree of substitution of the product is not high. , transparency and salt resistance are not good, easy to layer and deteriorate; the water-based method is easy to cause starch gelatinization, and the utilization rate of the etherifying agent is low, and generally cannot produce products with a degree of substitution greater than 0.1; traditional solvent methods usually use methanol or Ethanol is used as a solvent, and a slurry method with a high bath ratio is used to perform a single carboxymethylation denaturation on starch. This method improves the efficiency of the carboxymethylation reaction, and the product substitution degree is relatively high, but the product substitution degree reaches a certain level. Unstable viscosity, poor salt resistance and acid resistance

Moreover, the traditional solvent method consumes a large amount of organic solvent, and the production cost is relatively high