Study On Complex Starch-based Polymer Flocculant

The flocculation plays an important role in water treatment. The crucial property of a flocculant is its ability to hold quite high viscosity at low polymer concentration under the operating conditions of high temperature, high salt, acid and alkali environment. In the dissertation, the intermacromolecular complex flocculant is prepared through intermacromolecular complexation action and the properties of tolerance to temperature, resistance to salt and shear is investigated. A novel method to prepare the polymer flocculant with the tolerance to temperature, the resistance to salt and shear is found through the intermacromolecular complexation.A starch graft polymer starch-graft-acrylamide-2-acrylamino-2-methyl propanesulfonate (S-AM-AMPS) with excellent performance is synthesized. A azo initiator SH-1 is synthesized, and a complex initiator (NH₄)₂S₂O₈-CO(NH₂)₂-(SH-1) is prepared to efficiently initiate under the condition of low temperature and to greatly enhance the reaction efficiency. Then the ZnSe nanobelt with the special structure is prepared as the catalyst promoter in order to better improve the performance of the product. The optimum reaction conditions are confirmed by the orthogonal test. The traditional Mannich reaction is modified by pre-preparing hydroxymethyl dimethylamide through formaldehyde and dimethylamide, then tertiary amino and sulfonate type starch graft polymer TA(S-AM-AMPS) is prepared through the amination reaction of S-AM-AMPS and hydroxymethyl dimethylamide. The additive method greatly increases the conversion and the molecular weight of the product. Some analytical techniques, such as IR, ¹H-NMR, and SEM, are applied for the analysis of the products.The quaternary ammonium polymer P(AM-AAC) of high molecular weight is synthesized by acrylamide and acrylacyloxyethyltrimethyl ammonium chloride (AAC). The quaternary ammoniation reaction conditions are confirmed by the orthogonal test. The intrinsic viscosity and the quaternary ammonium of the product are 1175. 1mL/g and 20.1% respectively. Such as IR, ¹H-NMR are applied for the analysis of the products.The formation and effect factors of the complex solution TA(S-AM-AMPS)/P(AM-AAC) are investigated by the transmittance measurement of the solution. The results show that the complex of two oppositely charged polymers can form the homogeneous solution depending on the extent of the interactions, which promotes the theory of the preparation of homogeneous solution through intermacromolecular complex. The effects of temperature, salt and shear rate on solution viscosity are also studied by measuring solution viscosity at different conditions. Compared to two component polymervsolutions, the complex homogeneous solution exhibits better tolerance to temperature and better resistance to salt and shear. The net structure formed by the interaction of intermolecules makes the complex solution have better resistance to shear. Fluorescence spectrum, UV, IR, SEM, and DSC are applied for the analysis of the products.TA(S-AM-AMPS)/P(AM-AAC) is used to flocculate the wastewater of enhanced oil recovery. The results show that the flocculant can still hold the good flocculation efficiency under the operating conditions of high temperature, high salt, high shear rate. TA(S-AM-AMPS)/P(AM-AAC) with good flocculation efficiency is a promising flocculant.