阅读说明：本技术 一种顺丁烯二酸淀粉酯、制备方法及其应用 (Starch maleate, preparation method and application thereof ) 是由 蔡元林 郑秋鉴 郑秀旗 胡正波 于 2019-06-12 设计创作，主要内容包括：本发明涉及一种顺丁烯二酸淀粉酯的制备方法,在常温下,将顺丁烯二酸酐和甲醇加入容器中混合反应50-70分钟,然后升温至120℃-140℃,之后保持该温度并向容器中缓慢分多次加入淀粉和水,即得所述的顺丁烯二酸淀粉酯；加入淀粉时容器中的搅拌速率为15-20转/分钟,从开始加入淀粉到结束加入淀粉的时间为7-9小时,所述的顺丁烯二酸酐、甲醇和淀粉的质量比为100:35:500-800。顺丁烯二酸淀粉酯具有淀粉的较长分子链,本发明减水剂能保塌、抗泥、不离析泌水、不扒底、强度高、减少干缩变形、提高混凝土的抗冻性能、提高混凝土的抗腐蚀性、节约水泥。(The invention relates to a preparation method of maleic acid starch ester, which comprises the steps of adding maleic anhydride and methanol into a container at normal temperature, mixing and reacting for 50-70 minutes, heating to 120-140 ℃, keeping the temperature, and slowly adding starch and water into the container for multiple times to obtain the maleic acid starch ester; the stirring speed in the container is 15-20 r/min when the starch is added, the time from the beginning to the end of the starch addition is 7-9 hours, and the mass ratio of the maleic anhydride, the methanol and the starch is 100:35: 500-. The maleic starch ester has a longer molecular chain of starch, and the water reducer disclosed by the invention can be used for preventing collapse, resisting mud, preventing segregation and bleeding, preventing bottom scraping, being high in strength, reducing drying shrinkage deformation, improving the frost resistance of concrete, improving the corrosion resistance of concrete and saving cement.)

1. A preparation method of maleic starch ester is characterized by comprising the following steps: the method comprises the following steps:

at normal temperature, adding maleic anhydride and methanol into a container, mixing and reacting for 50-70 minutes, then heating to 120-140 ℃, keeping the temperature, and slowly adding starch and water into the container for multiple times to obtain the maleic acid starch ester;

the stirring speed in the container is 15-20 r/min when the starch is added, the time from the beginning to the end of the starch addition is 7-9 hours, and the mass ratio of the maleic anhydride, the methanol and the starch is 100:35: 500-.

2. A maleic acid starch ester, which is characterized in that: prepared by the method of claim 1.

3. An application of maleic acid starch ester in preparing a polycarboxylic acid water reducing agent.

4. The preparation method of the polycarboxylic acid water reducing agent is characterized by comprising the following steps: the method comprises the following steps:

(1) preparation of starch maleate

At normal temperature, adding maleic anhydride and methanol into a container, mixing and reacting for 50-70 minutes, then heating to 120-140 ℃, keeping the temperature, and slowly adding starch and water into the container for multiple times to obtain the maleic acid starch ester;

the stirring speed in the container is 15-20 r/min when the starch is added, the time from the beginning to the end of the starch addition is 7-9 hours, and the mass ratio of the maleic anhydride, the methanol and the starch is 100:35: 500-;

(2) preparation of polycarboxylic acid water reducing agent

And (2) mixing the polycarboxylic acid water reducing agent mother liquor with the maleic acid starch ester prepared in the step (1) according to the mass ratio of 100: 15-30.

5. The preparation method of the mother liquor of the modified polycarboxylate superplasticizer is characterized by comprising the following steps: the method comprises the following steps:

(1) preparation of starch maleate

At normal temperature, adding maleic anhydride and methanol into a container, mixing and reacting for 50-70 minutes, then heating to 120-140 ℃, keeping the temperature, and slowly adding starch and water into the container for multiple times to obtain the maleic acid starch ester;

the stirring speed in the container is 15-20 r/min when the starch is added, the time from the beginning to the end of the starch addition is 7-9 hours, and the mass ratio of the maleic anhydride, the methanol and the starch is 100:35: 500-;

(2) preparation of modified polycarboxylate superplasticizer mother liquor

And (2) mixing a polycarboxylic acid macromonomer with the maleic starch ester prepared in the step (1) according to a mass ratio of 90-70: 10-30 to obtain the mother liquor of the modified polycarboxylate superplasticizer.

Technical Field

The invention relates to the field of building materials, and in particular relates to starch maleate, a preparation method and application thereof.

Background

At present, a concrete structure is widely applied to a polycarboxylate superplasticizer, but a common polycarboxylate superplasticizer is sensitive to material change; due to different admixtures and different adaptability of cement of different manufacturers and the influence factors such as gradation of sandstone aggregate, change of mud content and the like, the mixing amount of the polycarboxylate superplasticizer is greatly changed in use, so that the performance of concrete in production is difficult to control, the conditions of poor workability, segregation and the like of the concrete in engineering construction often occur, and serious quality problems are brought to engineering.

In order to solve the series problems in the use of the polycarboxylic acid water reducing agent, the maleic acid starch ester is specially developed. The maleic acid starch ester has a longer molecular chain of starch, and can increase the cohesiveness and water retention of concrete after being compounded with the polycarboxylic acid water reducing agent, so that the concrete has better construction performance.

Disclosure of Invention

The invention provides a maleic acid starch ester, a preparation method and application thereof.

A preparation method of maleic starch ester comprises the following steps:

at normal temperature, adding maleic anhydride and methanol into a container, mixing and reacting for 50-70 minutes, then heating to 120-140 ℃, keeping the temperature, and slowly adding starch and water into the container for multiple times to obtain the maleic acid starch ester;

the stirring speed in the container is 15-20 r/min when the starch is added, the time from the beginning to the end of the starch addition is 7-9 hours, and the mass ratio of the maleic anhydride, the methanol and the starch is 100:35: 500-.

A maleic starch ester.

An application of maleic acid starch ester in preparing a polycarboxylic acid water reducing agent.

The preparation method of the polycarboxylic acid water reducing agent comprises the following steps:

(1) preparation of starch maleate

At normal temperature, adding maleic anhydride and methanol into a container, mixing and reacting for 50-70 minutes, then heating to 120-140 ℃, keeping the temperature, and slowly adding starch and water into the container for multiple times to obtain the maleic acid starch ester;

the stirring speed in the container is 15-20 r/min when the starch is added, the time from the beginning to the end of the starch addition is 7-9 hours, and the mass ratio of the maleic anhydride, the methanol and the starch is 100:35: 500-;

(2) preparation of polycarboxylic acid water reducing agent

And (2) mixing the polycarboxylic acid water reducing agent mother liquor with the maleic acid starch ester prepared in the step (1) according to the mass ratio of 100: 15-30.

The preparation method of the mother liquor of the modified polycarboxylate superplasticizer comprises the following steps:

(1) preparation of starch maleate

At normal temperature, adding maleic anhydride and methanol into a container, mixing and reacting for 50-70 minutes, then heating to 120-140 ℃, keeping the temperature, and slowly adding starch and water into the container for multiple times to obtain the maleic acid starch ester;

the stirring speed in the container is 15-20 r/min when the starch is added, the time from the beginning to the end of the starch addition is 7-9 hours, and the mass ratio of the maleic anhydride, the methanol and the starch is 100:35: 500-;

(2) preparation of modified polycarboxylate superplasticizer mother liquor

And (2) mixing a polycarboxylic acid macromonomer with the maleic starch ester prepared in the step (1) according to a mass ratio of 90-70: 10-30 to obtain the mother liquor of the modified polycarboxylate superplasticizer.

Compared with the prior art, the invention has the following beneficial effects:

the maleic acid starch ester has a longer molecular chain of starch, and can increase the cohesiveness and water retention of concrete after being compounded with the polycarboxylic acid water reducing agent, so that the concrete has better construction performance.

The water reducing agent can protect collapse: the slump loss of the concrete is not more than 1cm after 2 hours.

The water reducing agent of the invention resists mud: the change of the mud content does not influence the performance of the water reducing agent.

The water reducing agent of the invention does not separate and bleed: the molecular weight of the maleic starch ester is longer than that of the molecular chains of sodium gluconate and other small materials, so that the maleic starch ester is not easy to bleed and is not easy to separate.

The water reducing agent of the invention does not take off the bottom: the highest water reducing rate of the polycarboxylate superplasticizer can be achieved, about 40 percent, and the bottom is not scraped.

The water reducing agent has high strength: because the water reducing effect is obvious, the water consumption of the concrete is greatly reduced, so that the strength of the concrete can be greatly improved, and the compressive strength of the concrete is increased by about 10MPA compared with that of common polycarboxylic acid.

The water reducing agent reduces the shrinkage deformation and prevents concrete cracks: by adopting the water reducing agent, the compactness of each cubic concrete can be increased by 1-1.5%, and the drying shrinkage deformation is greatly reduced, so that the cracks of the concrete can be prevented.

The water reducing agent of the invention improves the frost resistance of concrete: the concrete adopting the water reducing agent of the invention is more compact and is not easy to seep water, so the frost resistance of the concrete can be greatly improved.

The water reducing agent of the invention improves the corrosion resistance of concrete: the compactness of the water reducing agent is improved by 1 to 1.5 percent compared with that of common concrete, and the corrosion of soft water to the concrete is reduced, so that the service life of the concrete is prolonged.

The water reducing agent disclosed by the invention can be used for improving the anti-permeability grade of concrete.

The water reducing agent of the invention saves cement: the water reducing agent has high water reducing rate, so that cement can be saved by 20-30%.

Detailed Description

The present invention is further described below with reference to examples. It will be understood by those skilled in the art that the following examples are not intended to limit the scope of the present invention, and that any modifications and variations based on the present invention are within the scope of the present invention.

C₄H₂O₃+CH₃OH＝C₅H₆O₄

C₅H₆O₄+C₆H₁₀O₅(replacement) of C₁₀H₂O₈+CH₃OH↑

The starch is preferably methanol of Meihui chemical industry limited company in Zhangzhou city and starch of Suzhou Kangnan fine chemical industry limited company;

the maleic anhydride is preferably maleic anhydride produced by Jomao of Shanghan province, Jinan province.