Starch sulphate and its application in concrete

Abstract

The present invention relates to starch sulfate and its preparation and application in concrete. Starch sulfate is prepared through one semi-dry process with chrlorosulfonic acid and starch in the molar ratio of 0.5-1.5 to 1 and organic solvent in 1-2 times volume of chrlorosulfonic acid, and through reaction for 1-4 hr. It has degree of substitution in 0.04-0.12, and molecular weight of (40-55)x10<6>. The starch sulfate is used as water reducing agent for concrete, and the added amount is 0.3-2 wt%. The starch sulfate itself is one kind of surfactant and possesses excellent application as concrete water reducing agent.

Description

technical field [0001] The invention relates to the preparation of starch sulfate and its application in concrete. Background technique [0002] The preparation method of starch sulfate mainly contains concentrated sulfuric acid, complexes of sulfur trioxide and amines, sodium bisulfite and sodium nitrate as sulfonating reagents. Wherein, concentrated sulfuric acid is a sulfonating reagent, and its product degradation of the obtained starch sulfate is serious, and inorganic salt sodium bisulfite and sodium nitrate are sulfonating reagents, and the degree of substitution of the product is low; The complex compound of sulfur trioxide and amine is Sulfonated reagents, although the degree of substitution is easier to control, have higher production costs and little industrial value. [0003] Water reducer is a concrete admixture that can reduce the water consumption of concrete mixing under the premise of maintaining the performance of concrete. ...

AI Technical Summary

Problems solved by technology

However, since calcium lignosulfonate is a by-product of pulp produced by the sulfuric acid process, although this type of water reducing agent is cheap, its water reducing efficiency is low, so its application in concrete, especially high-performance concrete, is limited.

In addition, sulfuric acid papermaking will produce a lot of pollution. With the improvement of papermaking technology, the raw material source of wood calcium water reducer is facing challenges

The disadvantage of naphthalene-based superplasticizers is that the concrete slump loses quickly, and the quality of composite products is unstable, which often affects the setting, hardening and durability of concrete; industrial naphthalene is a widely used industrial raw material, and the performance of naphthalene-based high-efficiency water-reducers The weakness of the water reducer and the insufficient supply of raw materials have become important factors restricting its further development, so it is imperative to develop a new water reducer