| The detergent is the essential daily necessities in people`s daily life, and it is mainly cleaning dirt and gives us sanitary environment for live. It is mainly composed of surfactants and detergent builders. The surfactants can decrease the surface tension of water and improve the clothing wetting. On the process washing, the surfactants can loosen and remove the fouling, and make the fouling emulsified or flocculated suspensions. Detergent builders are the most important constituents in detergents, which plays important role. The basic function of detergents builders include water softening capacity, providing alkalinity necessary for the washing water, buffering capacity of pH value, dispersion and suspension, washing liquid carrying fouling capacity and keeping storage stability of others additives. Because of fine washing-builder function, the sodium tripolyphosphate has been used as the detergent auxiliary, but it can bring the entrophication in the water and make environment pollution. The free phosphorus detergent builders of not only fine washing-auxiliary but also good coordination environment function are being given more and more all over the world. And the free phosphorus detergent builders have become a research hot in preparation and development. There are 4A and P zeolite,δ-layered sodium silicate, amorphous or active sodium silicate etc. in common free phosphorus detergent builders. Those do not completely replace the sodium tripolyphosphate because of its disadvantage in practical application. The properties of the low or free phosphorus detergent builders are not reached the national standard, although the free phosphorus detergent yield can get 180 million tons. Oxidized starch has become a promising detergent builder and excellent prospect of commercialization because of it excellent softening hard water capacity, buffering capacity of pH, good compatibility with other components, good biodedegradability and renewable raw material.In this paper, a novel and effective polycarboxylic group oxidized starch-- preparation principle of and preparation catalyst were studied. The basic properties, complexing capacity and compatibility capacity with surfactants and other components of oxidized starch were characterized. The preparation technology of oxidized starch was optimized. Good results have been achieved in the preparation process of oxidized starch.The catalyst for preparation oxidized corn starch and for used conditions is studied. The main contents include: selection of catalyst, species, active components, method of support, sintering temperature and using conditions. And one of the fine properties of catalysts was characterized. The studied and applied results showed that the catalyst have the characteristics of high active, long life time and high efficiency.The experimental conditions and technical parameters are studied and determined. The main contents include: effect of the reaction temperature, ratio of solid-liquid, hydrolyzation reaction time on the property of oxidized starch. The experimental conditions were optimized. The research results showed that the complexing capacity could reach 108.5 mgCa2+/g under the 1:5 ratio of starch and water, 1.5% catalyst, 180min reaction time, 6-8mL / min·aerated oxygen and 17g NaOH.The properties of physics and chemistry of oxidized starch are characterized. The content of carboxyl and carbonyl, molecular weight and molecular weight distribution of oxidized starch affect on the complexing capacity. Alkaline dotage and reaction time affect on the content of carboxyl and the molecular weight distribution. The molecular weight of oxidized starch degraded severely when the reaction time exceeds a certain time on a certain amount of alkaline which has much effect on the complexing capacity and cleaning effect. Different stirring methods have much effect on the molecular weight distribution. The amylopectin starch completely disappears and its molecular weight distribution concentrates with guide shell mixer. Using guide shell mixer can shorten reaction time and increase capability of complexation and detersive power, and the product could meet the demands of detersive power. But its disadvantage is demand of large amount of energy.The catalyzed oxidation starch using oxygen is not a location oxidation. The characterization by infrared and 13C-NMR show that the oxidation takes place on the C2, C3 and C6 changed to di-carboxylate and poly carboxylic oxidized starch, but the C-O-C of cyclic glucose is not cracking. Because it is one kind of polysaccharide containing carboxyl groups with carboxylate properties, softening hard water function of oxidized starch is one kind of complexing reaction. The oxidized satcrh have dispersion capacity and can affect on crystallization of calcium. The assisting washing and formulating principle of oxidized starch are investigated. The influences of several normal detergents auxiliary agent on the critical mice concentration (CMC) of sodium stearate in hard water are studied by use of surface tensions. The evaluation of their washing aiding activity is also made. It is showed experimentally that the reducing order of washing aiding effectiveness is sodium tripolyphosphate, oxidized starch and sodium polyacrylate. The oxidized starch should be taken as main detergent auxiliary agent for it superiority of higher washing aiding activity and no pollution to environment. The cooperativity of oxidized starch with surfactants and others auxiliary agent are investigated. The results shows that the oxidized starch has a good cooperativity with AEO9, AES and others detergent additives. We have gained the good property application recipe using oxidized starch by studying the recipe for sebum soiled swatch. And the detergency of detergent using oxidized starch is coincident with the market detergents. The study on formulae of free phosphorus detergent using oxidized starch provides an important the basis for popularization and application.The ratio of COD and BOD increases prolonging oxidation reaction time. The more than 0.4 of ratio of COD and BOD indicates that the oxidized starch is one of good biodegradable detergent builder. The determination of biodegradability indicates that degradation rate of oxidized starch gets to 64.9% in composting. The oxidized starch has small environmental pollution due to its easily degradable product.In order to realize industrial production of oxidized corn starch and test on effect of technology parameters on the product properties, commercial experiment on oxidized starch are studied. The technological conditions are optimized through the research on industrialization of oxidized starch. The main contents include: industrialization technology, four-effect dehydration and pressure powder injection processes. The volume density of need could be got by adjusting of pressure powder injection processes. The properties of oxidized starch are verified by commission. The test results of complexing capacity, assisting washing performance and cooperativity with surfactants and others auxiliary agent show that the oxidized starch has fine the properties of assistant washing. The detergent by oxidized starch has a very strong competitive ability in the market because it cost is lower than 2800 yuan per don and the addition in detergent is 25%. The pilot study on preparation oxidized starch provides an important the basis for popularization and application.
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