Studies On The Sizing Behavior Of Two Kinds Of Ionized Starch Sizes

The paste behaviors of two kinds ionized starches—the phosphorylated starch and the cationic starch was investigated, and the influences of the electrolytes involved in the modified starch were also evaluated.The phosphorylated starch was prepared by the reaction of refined cornstarch with sodium tripolyphosphate. The starch viscosity, hot paste stability, adhesion to fibers, and the behavior of starch film were evaluated. Then the effects of types and content of the electrolytes within phosphorylated starch on the above behaviors of the modified starch were also investigated. The electrolytes considered included sodium dihydrogen phosphate, sodium hydrogen phosphate, sodium phosphate, phosphoric acid, sodium pyrophosphate and pentasodium triphosphate. And by using sodium dihydrogen phosphate as model, the influences of the electrolytes upon the behaviors of phosphorylated starch-PVA1799 and phosphorylated starch-PVA1788 blends were also evaluated. It was found that the starch viscosity, hot paste stability, adhesion performance, and the behavior of starch film of the phosphorylated starch increase with the increase of the degree of substitution (DS). The electrolytes within the modified starch reduce sizing performance of the modified starch; the effects on the sizing behavior were different as the electrolytes were different. And the sizing performance was reduced with the increase of amount of the electrolytes. In addition, the electrolytes also reduce the sizing performance of starch-PVA blend pastes.In researching the performances of quaternary ammonium starch, a series of the cationic starch with different degree of substitution was prepared by using 3-chloro -2- hydroxypropyl -trimerthyl ammonium chloride that was made in our laboratory. And starch paste behaviors were tested. Then the effects of the electrolytes on the behavior were evaluated in term of the viscosity, hot paste stability, adhesion behavior, and the performance of starch film. And the effects of type and content of the electrolytes within cationic starch on the sizing behaviors of the modified starch were investigated. It was found that the hot paste stability, adhesion behavior, and the performance of starch film of the cationic starch increase with the increase of the DS value. The electrolytes within cationic starch reduce sizing performance of the modified starch. And the sizing behaviors show much different sensitivity to different electrolytes. In addition, the sizing performance was reduced with the increase of amount of the electrolytes.