Alkane-bridged lignin-based polymer as well as preparation method and application of lignin-based polymer

Abstract

The invention discloses an alkane-bridged lignin-based polymer as well as a preparation method and an application of the lignin-based polymer. The preparation method comprises the steps of dissolving lignosulfonate in water, adding alkalis substances, and then adding polyhalogenated alkane monomer or polyhalogenated alkane monomer with aromatic rings to the reaction liquid and carrying out bridging polymerization to obtain the high-molecular-weight lignin-based polymer. The prepared lignin-based polymer has a weight-average molecular weight of 10000Da-500000Da as well as relatively low molecular weight dispersity. The lignin-based polymer disclosed by the invention has the advantages of relatively low raw material cost and rich raw material source, the process is easily operated, when the lignin-based polymer is used in the coal water slurry and titanium dioxide slurry, the dispersion properties of the lignin-based polymer can be significantly improved at a low mixing amount and the lignin-based polymer is a novel lignin-based polymer with wide application prospects.

Description

technical field [0001] The present invention relates to a lignin-based polymer, in particular to an alkane-bridged lignin-based polymer and a preparation method thereof. Application in suspension systems. Background technique [0002] Lignin is a product recovered from the black liquor of alkaline pulping in the paper industry. There are many active groups in its molecular structure, such as aromatic groups, phenolic hydroxyl groups, alcoholic hydroxyl groups, methoxyl groups, carbonyl groups, carboxyl groups, and conjugated double bonds. etc., and various chemical modification reactions can be carried out. A common modification method is to effectively improve the water solubility of lignin through sulfonation, but sulfonation alone does not increase the molecular weight of lignin, and cannot maximize its application performance. Molecular weight is one of the important structural indicators of lignin-based water-soluble polymers, and is an important factor affecting the ...

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Problems solved by technology

(1) Formaldehyde / acetone polycondensation method [CN101322927A; CN101709113A; CN101921639A; CN102923990A], this type of modified product has better dispersion and viscosity reduction ability, but the dosage is higher; a large amount of toxic reagent formaldehyde needs to be added, and the molecular weight increase is limited

(2) graft copolymerization method [CN1054078A; CN1071436A; CN1693342A; CN101440287A; CN102294199A; CN103301821A], this type of modification method is under the effect of initiator, unsaturated monomer is inserted in the lignin, and condition is harsh, and Lignin activity is low, resulting in a generally low grafting rate

(4) Alkylation reaction, the patent [US3407188] uses haloalkane or alkyl sulfate and lignin to produce Mannich reaction to prepare lignin quaternary ammonium salt, the alkyl chain adopts 1 to 4 carbons, and the long-chain halogenated hydrocarbon is then Difficult to react; U.S. patents [US7691982; US4781840] use halogenated hydrocarbons, alkyl sulfates and epoxy derivatives to carry out alkylation reactions on lignin, but the purpose is to improve the lipophilicity of lignin, which can be used in oil displacement agents and flotation agents, etc.; patents [CN1304950A; CN103254882A; US4739041; US5094295] use halogenated straight-chain alkanes as alkylating agents to introduce alkyl chains into lignosulfonate molecules to improve the lipophilicity of lignin, making it Both water and oil have a certain solubility, which has little influence on its molecular weight; patent [CN102580610A] prefers chlorinated paraffin to carry out alkylation modification on lignosulfonate, and synthesizes lignosulfonate alkylation modified surface Active agent, in the product aqueous solution that mass concentration is 1%, surface tension can be reduced to 29.299mN / m, but reaction condition is harsh, with the mixed solution of organic solvent (alcohol, ketone or ether) and water as solvent and with alkaline Organic amines (tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyridine or pyridine derivatives) are catalysts and need to be reacted under the protection of an inert gas, which is not conducive to its industrial application

(5) Enzyme catalysis, patent [CN103088067A] uses peroxidase to catalyze the synthesis of high molecular weight sodium lignosulfonate polymer, the prepared sodium lignosulfonate polymer has a weight average molecular weight of 30000Da~100000Da, which improves the resistance to solid particles The dispersion performance of the suspension system, but the large dispersion and the high cost of peroxidase limit its application

[0005] Generally, researchers believe that the introduction of lipophilic alkyl chains into lignin or lignosulfonate will reduce water solubility, which is not conducive to the synthesis of high molecular weight, high water-soluble lignin-based polymers

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