Studies On The Adhesion Of Acetylated And Cross-linked Starch Sizes

The adhesion behaviors of acetylated and cross-linked starches were emphasized investigated. The method for measuring the viscosity and hot-paste viscosity stability of converted starch with Brabender Micro-Visco-Amylo-Graphy(M-V-A-G) was also explored.The adhesion behaviors of acetylated starch sizes to fiber substrates were evaluated in terms of maximum strength and work to break of a slightly sized roving. The relevant relations between the adhesion behaviors and substitution degree of acetylated starch, source of starch, and composition of starch-PVA blend were investigated by using an impregnated roving method. The experiment results demonstrate that the modification of starch enhances the adhesion behaviors to fibers, and the adhesion decreases with the starch type as the order of potato starch>corn starch>tapioca starch. Compare with native cornstarch/PVA1788, the same effect could be obtained by using acetylated cornstarch-PVA1799 blend when the degree of substitution is only as less as 0.019.The cross-linking starch which was prepared with reacting cornstarch with sodium trimetaphosphate as cross-linking agent. The agent does not either pollute environments or harm to mankind. The effect of the degree of cross-linking to viscosity, hot-paste stability, and adhesion were researched. The experimental results demonstrate that the cross-linking modification of starch enhances the hot-paste stability. The adhesion behaviors to fibers were not affected greatly when the sedimentation value of starch paste is between 2.65mL to 3.6ml. However, the adhesion decreases markedly if the starch sizes are excessively cross-linked.In the course of studying the method of measuring the viscosity and hot-paste viscosity stability of starch with M-V-A-G, a series of comparison experiments were done with nature starch and modified starch sizes, and the following conclusions were concluded. In the condition of 6% concentration of starch paste, holding 3 hours at 95℃, heating rate at 7.5℃/min and the rotating rate of measuring bowl at 250r/min, the values of nature starch measured by M-V-A-G were more stable and similar to the values measured by NDJ-79. But with the same set of parameters, the stability of values of modified starches with lower viscosity was not satisfied.