The Study Of Dry Method Of Technological Preparation Of Carboxymethyl Starch For Sizing

Textile warp sizing is very important to weaving and it can endow with mechanical properties of warp in order to improve weaving efficiency and the quality of woven fabric. During the process of printing and dying sizing materials that are desized from fabrics will pollute environment if they will not be well degraded. Currently, environment protection is a hotspot. Textile industry should use some sizing materials that have no pollution of the environment in order to harmonize the development of economy with environmental protection. By comparing some sizing materials the conclusion is that carboxymethyl starch have good sizing properties and is degradable in order to reduce the pollution of environment. Dry method of producing carboxymethyl starch was researched in paper. The technological preparation of carboxymethyl starch and properties of sizing were also studied.In order to improve degree of substitution some factors were investigated including the quantity of adding alkali, the ratio of alkalization, the temperature of alkalization, the quantity of adding chloroacetic acid, the temperature of etherization and reaction time.Degree of substitution was the main index in the testing. The optimum conditions were achieved by means of single factor experiments and orthogonal experiments. The degree of substitution of carboxymethyl starch produced by us was 0.46. Complexometric method of degree of substitution of carboxymethyl starch was improved by selecting PAN (1,2-pyridyl azo -3-naphthol). By controlling the adding quantity of indicator and adjusting pH value color change is clear in order that results were accurate and stable. So it is suitable for testing in the laboratory.Carboxymethyl starch was identified by infrared spectra and scanning electron microscope. Properties of carboxymethyl starch was tested and compared with oxidized starch. The solubility of carboxymethyl starch was better than oxidized starch's. The solubility was improved with the increasing of degree of substitution. The content of chlorin ion was decreased clearly after carboxymethyl starch was washed by ethanol. The Brabender viscosity curve of carboxymethyl starch had been showed that the capability of paste of carboxymethyl starch was different with raw starch's. The gelatined temperature of carboxymethyl starch was decreased and cold viscosity was reduced slightly. The capability of gelatin was lower than raw starch.Sizing properties of carboxymethyl starch was tested. The viscosity and it's stability of carboxymethyl starch were determined. For sizing cotton yarn with different degree of substitution of carboxymethyl starchsize pick-up, abrasion resistance, tensile strength, elongation and hairiness are superior to raw yarn and yam sized by oxidized starch. Moreover, the more sizing properties were the higher degree of substitution was. Sizing properties of carboxymethyl starch which degree of substitution is 0.46 is optimum and meet the demand of sizing.