Study On Preparation Of Succinate Starch Size And Sizing Properties

Starch has many advantages when used as sizing material.The ring and polyhydroxyl structure of starch lead to the starch slurry film "hard and brittle" and insufficient adhesion to the fiber,which cannot meet the size requirements.In this paper,succinic acid esterified starch was prepared by semi-dry esterification reaction with starch using succinic anhydride as esterifying agent.The preparation process parameters,adhesion property,sizing film property and sizing property of succinic acid esterified starch were discussed,which laid the experimental foundation for practical application of succinic acid esterified starch in sizing field.Firstly,the effects of preparation process parameters such as catalyst dosage,water content,reaction time and reaction temperature on the degree of substitution and reaction efficiency of succinic acid esterified starch were studied.Thus,the optimal technological parameters for preparing succinic acid esterified starch were determined as follows:the amount of catalyst was 4%of the mass of starch,and the water content should not be controlled too high at 25%,and the reaction time was controlled at 2 h,and the reaction temperature was 125℃.Secondly,five groups of succinic acid esterified starch with different degrees of substitution were prepared by changing the amount of esterifying agent under the optimal process parameters.Their adhesion and slurry film properties were studied to determine the range of optimal substitution degree of succinic acid esterified starch.The results showed that:when the degree of substitution of succinic acid esterified starch increased from 0.065 to 0.123,the adhesive force of starch slurry to polyester fiber first gradually increased,and the maximum adhesive force was 114.62N when the degree of substitution reached 0.098,and then began to decrease.The adhesion to cotton fiber also increases gradually at first,and reaches the maximum value of 72.08N when the degree of substitution reaches 0.098,and then gradually decreases.When the degree of substitution of esterified starch increased from 0.065 to 0.123,the breaking elongation of esterified starch slurry film first increased,and when the degree of substitution of starch reached 0.082,the breaking elongation of the slurry film reached a maximum of 3.67%,and then began to decrease.In summary,when applied to the field of textile sizing,the degree of substitution of succinic acid esterified starch should be controlled between 0.082 and 0.098.Finally,for the conventional 13tex 65/35 polyester-cotton blended yarn,the succinic acid esterified starch with PVA blending size with 0.098 degree of substitution was selected for the sizing experiment.It is compared with the sizing effect of the oxidized starch and PVA blended size commonly used in polyester-cotton blended yarn under the same conditions.The experimental results showed that the sizing performance of PVA blend size with succinic acid esterified starch was better than that of PVA blend size with acidolysis starch and PVA blend size with oxidized starch.Compared with the acidolysis starch/PVA blend size,the enhancement rate of sizing yarn increased by 7.82%and the elongation rate decreased by 1.92%.Compared with the oxidized starch/PVA blended size,the yarn enhancement rate after sizing increased by 3.22%and elongation rate decreased by 1.11%.In addition,the yarn wear resistance and feather sticking performance were significantly improved after sizing succinic acid esterified starch/PVA blend.In summary,the application of succinic acid esterified starch in sizing polyester/cotton blended yarn can obviously improve the sizing performance,and the application prospect of replacing oxidized starch in actual sizing is broad.