Hydrophobically Associating Cationic Starch Preparation, Properties And Flocculation Performance Study

Starch, which is much more abundant than any other organic matters in the nature, is the most abundant organic resource that human can extract. A starch molecular contains many hydroxyls. Starch properties can be modified through hydroxylation such as esterification, etherification, oxidation and cross-linking. Modified starch has many characterization with organic macrornolecule, including non-poisonous; biodegradation completely and sound recyclation in nature. There are many ways for start modification, in which graft copolymerizing is a core element. Graft copolymerizing of starch and vinyl monomers with its advantages of simplicity and the result of getting excellent graft copolymers, can be used for paper making, weave, foodstuff, printing and dyeing, medicament, treatment waste water, adherence and exploitation of gasoline. As petroleum and coal are drying up and serious energy sources crisis exhaustion and environmental pollution, R&D and application of starch-modified has attracted a lot of attention.Hydrophobically associating water soluble polymer, which has hydrophobic association, salt-thickening behavior, temperature resistance, shear-thinning behavior and surface activity, it is a water soluble polymer with a few hydrophobic groups in the hydrophilic macromolecular chain. So, it has great practical potential in many fields like oil/gas exploitation, wastewater and sludge treatment, coatings, biological drugs and engineering materials for projects. It was synthesized in which the continuous phase was cyclohexane, dispersing agent was Span80/Tween80 and initiator was redox initator. The soluble properties and the effects of grafting properties with dispersing agent, reaction temperature and time were discussed.This paper is try to illustrate the preparation of PSOAMDA through graft copolymerization of starch, hydrophobical monomer (OA), cationic reagent (DMDAAC) and AM by inverse suspension polymerization. At the same time, the hydrophobically associating cationic starch is examined with properties and practice foreground.1, During the preparation of hydrophobically associating cationic starch,â… have gotten PSOAMDA in innovate through inverse suspension polymerization, using redox initator (K₂S₂O_8-NaHSO₃) to make St- OA- AM- DAMDAAC graft copolymerization happen through considerable examinations, during the research each effects of grafting copolymerization, the best preparative conditions has defined: hexamethylene as continuou sphase, multiple dispersing agent by Span-80 and Tween-80.â… have also researched the effects of monomer, initiator, the dosage of dispersing agent, ratio of oil and water, reaction temperature and time to the monomer conversion, graft percentage and graft efficiency of copolymer; measured cationic degree, quality of viscous molecule and apparent activating enzymes. The grafted matter was characterization with IR, X-ray diffraction, ESM.. The results showed that the using of K₂S₂O_8-NaHSO₃ can speed up polymerization in low temperature; under the conditions that ratio of oil and water is 2:1, the quality of Span -80 and Tween-80 is 2:1, the concentration of K₂S₂O₈ and NaHSO₃ is 3.0mmol/L, ST:AM:DMDAAC:OA is 4: 7.4: 1.5: 0.6, the concentration of monomer is 4.6mol/L, reaction temperature is 30℃; reaction time is 3h and the concentration of emulsifiers is 5%, The graft percentage and graft efficiency of copolymer are 43.2% and 56.4% respectively. The monomer conversion and cationic degree are 92.6% and 15.4% respectively. IR Spectrogram proved that the compounded copolymer is the copolymer we wanted; X-diffraction defined that starch did graft copolymerization; ESM showed that reactions happed on the surface of starch grains and the surface turned slick from being coarse. Apparent activating enzymes are 24.76kJ/mol. The whole speed formulation reasoned by reaction mechanism tallies the results of this examination.2, During the compounding of octadecyl acrylate,â… introduced solid super acid as catalyst and esterification with melting for the first time.â… have also researched effects of the mole ratio of acrylic acid and octadecyl alcohol, and hydroquinonone as .the dosage of catalyzer and hibitor, reaction temperature and time. The production was further verified with IR. The experiment results showed that the optimum reaction condition were as follow: the molar ratio of acrylic acid to octadecyl alcohol was 1.2,the amounts of solid super acid and hydroquinonone were 6.0% and 0.8% respectively, reaction temperature and time were 120℃and 3h. In this condition,the percentage of esterification of octadecyl acrylate was 97%.3,During the research on the solution property of hydrophobic associated cationic starch,â… have done research effects of the viscosity of the PSOAMDA, reaction conditions, hydrophobic, salt resistance, temper resistance, shear thinning ability and surface activity. Examination results confirm that: the viscosity of cationic starch has close relationship with ratio of reactants, reaction temperature, reaction time, dosage of catalyst, and so on. The influence of OA to viscosity of PSOAMDA has a best value. Too much dosage will make copolymers unsolvable; being above critical aggregation concentration, in terms of intra-and inter molecular hydrophobical associations, the apparent viscosity of copolymer solutions increases notably with increasing copolymer concentration,it has obvious showed hydrophobic association behaviour. The critical aggregate concentration is descends in brine solution, the viscosity of the system in 0.20mol/L NaC1 is higher than in pure water, copolymer had excellent viscosity retention in brine. The copolymers have excellent salt resistance behaviour. The viscosity of PSOAMDA descends when system temperature increases, and it reveal temper resistance which has higher viscosity than unassociated copolymers; It also has shear- thinning ability, and the viscosity increases during the process of shearing recoved. SDBS, the anionic surfactants has the viscosifying ability; besides of good viscosifying ability, PSOAMDA also has some surface activity, which increases along with the increase of concentration inorganic salt and temperature.4,During the research of the ftocculation property of hydrophobic associated cationic starch,â… have done research on the flocculation of kieselguhr suspension. The flocculation property experiments showed that the best flocculation effect can be got when PSOAMDA quality is 3～7mg/L, pH value of aqueous solution is around 4～10 and solution temperature is around 20～50℃. Its flocculation ability increases as dosage of flocculant and cationic degree increase; the time of flocculation is shortened; transparency of solution increases; Weak acid situation contributes more or less to the stability of PSOAMDA;â… have also elaborated and concluded flocculation theory of macromolecule flocculant; on the base of the elaboration and conclusion,â… have theoretically done the initial inference and explanation on the theory of PSOAMDA: its flocculation in mainly is based on mechanisms of absorption-bridging and electricity counteract; agglomeration have contributed a lot to the whole flocculation effect.5,During the flocculation examination of hydrophobic associated cationic starch,â… have researched the flocculation ability of PSOAMDA to water with algae in Dian Lake, waste water with oil, city waste water and plant extract situation through determining the changes of pH value, transparency and the COD before and after the disposal to determine the property of its flocculation;â… got the results that: PSOAMDA has strong flocculation and decoloring effect to real waste water. During the process of disposing flocculation in simulate waste water with oil, that PSOAMDA has a great disposal efficiency in the high-concentration-oiI sewage treatment. When the oil concentration is over 2000ppm, the disposal efficiency will reach up to at least 60% in 10 h. The flocculation disposing in Dian Lake showed the COD removal efficiency reached up to 71.3% when PSOAMDA was 3mg/L. The results showed that COD removal efficiency reached up to 73.3%when PSOAMDA was 6mg/L. During treatment plant extract situation, when PSOAMDA was 25mg/L, temperature is 50℃, pH value is 6.0,the transparency and purity of products is best value. The flocculation performance is better than cationic PAM through contrasting examination of flocculantion ability of cationic flocculant in the market.6,â… have compared the inverse suspension polymerization and aqueous solution polymerization. The aqueous solution polymerization didn't obtain hydrophobic associated cationic starch. The inverse suspension polymerization didn't obtain products which has high molecular weight. However, the process is stable; reaction is easy to be controlled; offset process is simple; dissolution is more smoothly; the process of crushing and slicing can be avoided. It has good prospect in industrial production.