Synthesis And Properties Of2,4-bis-sulfonic Anilino-[1,3,5]-Triazine-6-yl-Starch Ether And Dual Modified Starch Derivatives

Starch is regarded as a kind of ideal polymer materials for its properties of extensive resources, biodegradability and no toxicity. Sulfonic acid groups have properties of acid and alkali-resistance and salt-resistance, so that starch derivatives containing sulfonic acid groups are applied extensively. Generally, the starch derivatives are prepared by direct sulfonation reaction of starch. However, the degree of sulfonation obtained from this method, is low and the starch chains are usually degraded in the process of sulfonation, which affects much the application of the starch derivatives. In this thesis, a series of new starch ethers and composite modified starch ethers containing sulfonic acid groups were designed and synthesized with use of novel starch etherification agent containing sulfonic acid groups. Moreover, the synthetic routes and the rheo logical properties of the products were also studied.Novel etherification agent,2,4-bis-sufonic anilino-6-chloro-[1,3,5]-triazine (BSTS) was prepared by nucleophilic substitution reaction of cyanuric chloride and metanilic acid. The effects of the reaction conditions on the yield were investigated in detail. At the optimal reaction conditions, the yield of BSTS can reach98.2%. The structure of the etherification agent was characterized by ESI-MS, FT-IR and1H-NMR.2,4-bis-sufonic aniline-[1,3,5]-triazine-6-yl-starch ether (BSTSS) with BSTS as etherification agent was synthesized. By changing the molar ratio of BSTS to starch, a series of BSTSS with different degree of substitution (DS) were obtained. The optimal reaction conditions in the DMSO homogeneous system with alkali was as catalyst were investigated. At the optimal conditions, the reaction efficiency in the preparation of BSTSS can reach77.5%, and the molecular weight of BSTSS was2-3×106. Some new rheo logical properties of the BSTSS solution appeared because of the electrostatic repulsion and steric hindrance of the big components containing sulfonate groups in BSTSS. For example, when the solution concentration is below5%and the DS of BSTSS is lower than0.56, the viscosity of the BSTSS solution is below520mPa.s in the range of pH2-12. While, when the solution concentration is5%, the viscosity of the solution reached2073mPa.s at pH2-12. In addition, the BSTSS showed properties of excellent water-solubility, acid and alkali-resistance, temperature and salt-resistance.Composite modified starch ethers containing carboxymethyl and sulfonic acid groups (defined as BSTS-CMS) were prepared by use of BSTS and carboxymethyl starch (CMS) as materials. The synthesis process was investigated and the optimal reactions are determined. It presents when the DS of the carboxymethyl starch is below0.43, the molar ratio of BSTS to CMS is0.6:1, the reaction temperature is110℃and the time is210min., the reaction efficiency can reach55%and the DS of BSTS-CMS reach0.33. The study on the viscosity of BSTS-CMS solution indicated that by incorporating the sulfonate groups into the carboxymethyl starch, the composite modified starch derivatives showed evident properties of resistance to salt and temperature, anti-shearing force and anti-electrolyte compared with the carboxymethyl starch.Oxidized starch containing sulfonate groups (BSTS-OS) was synthesized by reaction of oxidized starch and BSTS. The investigation on the application of BSTS-OS as a water reducing agent of the cement exhibited that the fluidity of cement pastes reached230mm when the dosage of the BSTS-OS with BSTS DS of0.31was0.45%; however, when the dosage of the conventional water reducing agent of naphthalene series was1.5%, the fluidity of cement pastes only reached210mm. In addition, the BSTS-OS has general applicability on different kinds of cements. Therefore, the obtained BSTS-OS was a high effective water reducing agent.