| At present, Starch, polyvinyl alcohol (PVA), acrylic acids are the three main sizing forwarp sizing in the textile. With the development of science and technology, the starch size asnatural renewable resources, has attracted more attention because of its abundant source andlow price, which can also meets the requirement of environmental protection. Now,low-carbon and energy saving are advocated by our country with the economic development.The innovation in size research and sizing process is necessary for eco-textiles and naturalsizing in weaving industry. Therefore, the usage of environmental starch is the importantdirection of ecological sizing technology.The partial-gelatinized starch, performance of sizing and sizing technology were studiedsufficiently in this thesis. First, using native starch and modified starch (PR-SU) as rawmaterial, partial-gelatinized starch sizing was prepared by high-pressure steam method andthe effect of sizing concentrations, proportions, temperature on the viscosity and stability ofpartial-gelatinized sizing was studied in detail. Second, the effect of temperature on thegelatinization of partial-gelatinized starch was analyzed by differential scanning calorimetry(DSC) to study the properties of partial-gelatinized starch sizing, the morphology ofpartial-gelatinized starch granules with different degree of gelatinization was observed byLeica polarizing microscope. Finally, both the partial-gelatinized with best feed ratio andpreparation temperature and full-gelatinized were used to size the pure cotton, then theproperties of these two kinds of sizing were compared carefully. The contents and researchresults are shown as follows:(1) The partial-gelatinized starch sizing was prepared by self-designed devicesuccessfully, the results show that when the solid content of sizing is10%，native starch: PR-SU is4:1(wt/wt), sizing temperature which was adjusted through the steamis65℃the partial-gelatinized starch sizing with low viscosity (6.6~7.5mPa·s), well liquidityand stability at room temperature can obtained, which is suitable for sizing.(2) DSC was used to measure the degree of gelatinization sizing, the results show thatthe prepared sizing is partial-gelatinized and the degree of gelatinization will increased withtemperature rise. The morphologies of starch granules in native starch, different degree ofpartial-gelatinized and full-gelatinized were observed by Leica polarizing microscope, it canbe found out that surface of native starch granule is smooth and the size is uniform, thepolarization cross phenomenon can also be observed. The degree of gelatinization increaseswith the rise of temperature, and the starch granules swell gradually, which results in thecrack of surface, the disintegration of crystal and disappearance of polarization cross. Andthe volume of starch becomes larger and larger until completely broken.(3) The pure cotton warp yarn was sized by partial-gelatinized starch sizing at roomtemperature, the results show that the sizing rate of partial-gelatinized starch is less than thatof fully gelatinized starch, the strength of sizing yarn and wear resistance increasesignificantly, while the hairiness reduced.(4) The influence of the sizing temperature (35,45and55℃) and squeeze force on the performance of sizing yarn was further studied, the results show that sizing rate increasewith the rise of temperature, while it reduced with the increase of squeeze force.(5) The surface and the slice of sizing yarn were analyzed by the microscope, it can befound that the body of sizing yarn is closer than that of native yarn; the edges and internal ofyarn size by partial-gelatinized starch is dark, but darkness and area is less than that of yarnsized by full-gelatinized starch. The possible reason is that the viscosity of full-gelatinizedstarch is high, thus the surface coating is large. The partial-gelatinized starch sizing has lowviscosity, well liquidity, therefore the content internal sizing is more than that offull-gelatinized starch. |
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