A kind of preparation method of water-in-water emulsion type cationic polysaccharide biological flocculant

Abstract

The invention relates to a preparation method of a water-in-water emulsion-type cation polysaccharide biological flocculant. The preparation method is characterized in that: an auto-polymer or a copolymer of several types of unsaturated cation monomers is used as a stabilizer, a non-ionic polysaccharide biological flocculant is used as an auxiliary stabilizer, an aqueous solution of inorganic salts is used as a continuous phase, and by virtue of certain technological control, free radical polymerization is performed in an internal phase aqueous solution to form stable and dispersed cation polysaccharide biological flocculant emulsion containing micro polymer particles, wherein the solid content is more than or equal to 30 percent, the appearance viscosity is 300 to 10000 mPa.s, the average particle size is less than or equal to 10 micrometers, and the stability is more than or equal to 6 months. The product is simple in synthetic process, high in solubility, degradable, good in flocculation effect and free from secondary pollution, can be used for treating urban sewage and industrial waste water and dehydrating sludge, can be used as a filter aid and a retention aid in the papermaking industry, can be used for plugging adjustment and sewage treatment in oil fields and the like and is wide in application prospect and high in environmental protection value.

Description

technical field [0001] The invention belongs to the technical field of polysaccharide biological flocculant modification technology, in particular to a preparation method of a water-in-water emulsion type cationic polysaccharide biological flocculant. Background technique [0002] If the traditional aqueous solution polymerization method is not properly controlled, due to the uneven heat transfer and local exotherm during the polymerization process, it will lead to uneven polymerization and even gel formation. The apparent viscosity of the solid content product is very high, which affects the flocculation effect and brings a lot of inconvenience to the later treatment or use. The inverse emulsion polymerization method that appeared later, due to the mild reaction conditions, uniform and easy-to-control system temperature, less side reactions, and the obtained product has a relatively high molecular weight and a narrow distribution, high solid content and low apparent viscosi...

AI Technical Summary

Problems solved by technology

[0002] If the traditional aqueous solution polymerization method is not properly controlled, due to the uneven heat transfer and local exotherm during the polymerization process, it will lead to uneven polymerization and even gel formation. The apparent viscosity of the solid content product is very high, which affects the flocculation effect and brings a lot of inconvenience to the later treatment or use

The inverse emulsion polymerization method that appeared later, due to the mild reaction conditions, uniform and easy-to-control system temperature, less side reactions, and the obtained product has a relatively high molecular weight and a narrow distribution, high solid content and low apparent viscosity, it is a good solution to the past. The problem that the product is difficult to dissolve greatly shortens the time for dispersion and dissolution, but a large amount of organic solvents and surfactants are required in the preparation process, which not only increases production costs and safety hazards, but also easily causes secondary pollution to the environment

[0003] At present, most of the natural polymer materials with properties similar to polysaccharide bioflocculants, such as starch, cellulose, chitin, etc., are prepared by inverse emulsion polymerization and aqueous solution polymerization. The patent with publication number CN101665554A is prepared by inverse emulsion polymerization Starch graft copolymerization cationic flocculant, the water phase contains a certain proportion of starch, acrylamide and cationic monomer, then add the prepared water phase solution to the oil phase dissolved in a certain amount of emulsifier, and finally add the remaining Acrylamide, this method of adding nonionic monomers twice can overcome the problem of low grafting ratio of cationic monomers caused by the high reactivity ratio of nonionic monomers in the first addition to a certain extent, but there are Secondary pollution of the oil phase, and the cost of the oil phase is higher

In addition, the patent publication No. CN1884324A mentions a preparation method of cationic acrylamide copolymer water-in-water emulsion, wherein said water-in-water emulsion polymerization has the advantages of inverse emulsion polymerization, the solvent is all water, but because of hydrophobic In the presence of groups, it is difficult to achieve milk formation and maintain stability without delamination in order to obtain high solid content products. For this reason, it uses multi-stage polymerization and adds auxiliary stabilizers (mainly polyols) to alleviate the problem. The contradiction between the polymerization speed and the precipitation speed facilitates milk formation, thereby increasing the content of active substances and the stability of the emulsion. Such polyols include glycerin, polyethylene glycol, and polysaccharides such as modified tapioca starch, Amylopectin, dextran or methyl ester cellulose, because this method adopts the method of adding monomers for multiple times in a row, there are problems such as slightly complicated process procedures

[0004] It can be seen that there are many problems in the traditional method of synthesizing water-soluble cationic polymers, such as increasing the solid content while the product has poor fluidity or even gelation, difficult to dissolve, organic solvent pollution or low active content and low molecular weight Unavoidable problems at the same time will bring a lot of inconvenience to subsequent processing or use

Water-in-water emulsion polymerization can solve many of the above problems, but in terms of milk formation and emulsion stability, the control of the process is complicated