A modified lignosulfonate water reducer and its preparation method

Abstract

The invention discloses a modified lignosulfonate water-reducing agent and a preparation method thereof. Firstly, lignosulfonate is oxidized by an oxidizing agent so as to improve the chemical activity of the lignosulfonate, and then the modified lignosulfonate is polymerized with unsaturated carboxylic acid and salts thereof, allyl glucose, and vinyl phosphonic acid and salts thereof to achieve a purpose of chemical modification, so that the modified sodium lignosulfonate is connected to a carboxyl group, a glycosyl group, a phosphonic group and other anionic groups for further improving the performance of a product. The modified lignosulfonate water-reducing agent is mainly used for improving the performance of concrete.

Description

technical field [0001] The invention belongs to the technical field of concrete admixtures, in particular to a modified lignosulfonate water reducer and a preparation method thereof. Background technique [0002] Lignin, also known as lignin, is the only non-petroleum resource in nature that can provide renewable aryl compounds. Lignin widely exists in the xylem of most terrestrial plants, accounting for about one-third of the biomass of terrestrial plants, and is the second largest natural organic matter with an annual output of about 60 billion tons. Through sulfonation, lignin undergoes chain scission and condensation reactions to generate a non-polar aromatic group, such as alkylbenzene, and polar sulfonic acid group, methoxyl group and hydroxyl group, which is an anionic high Molecular surfactant, that is, lignosulfonate. Lignosulfonate can be directly used as a common water reducer for concrete, but it has defects such as low water reducing rate, excessive retardatio...

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Problems solved by technology

Lignosulfonate can be directly used as a common water reducing agent for concrete, but it has defects such as low water reducing rate, excessive retardation, uneven bubbles, etc.

[0003] Scholars at home and abroad have done a lot of research on the preparation of high-efficiency water reducers by modifying lignosulfonate in the late 1970s. The modification methods can usually be divided into physical modification and chemical modification, and the cost of physical modification is high. , the improvement of water reducing performance is not obvious, chemical modification can change the molecular structure of lignosulfonate from the perspective of molecular design, improve the surface activity of lignosulfonate, it has the advantages of many modification means and great controllability, but Often modification research and application research are disconnected, resulting in high modification costs, large fluctuations in performance of modified products, and difficulties in large-scale industrial production and popularization and application

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