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Scheme for promoting 2-mercaptoethanol in the water reducing agent industry
2024.10.31
1、 Introduction to Water Reducing Agents
Water reducing agent is a concrete admixture that can reduce the amount of water used in mixing while maintaining the basic consistency of concrete slump. After adding concrete mixture, it has a dispersing effect on cement particles, which can improve its workability, reduce unit water consumption, and improve the fluidity of concrete mixture; Or reduce the unit cement consumption to save cement.
Water reducing agents are usually classified according to their chemical composition into lignin sulfonate water reducing agents, naphthalene based high-efficiency water reducing agents, melamine based high-efficiency water reducing agents, aminosulfonate based high-efficiency water reducing agents, fatty acid based high-efficiency water reducing agents, and polycarboxylate based high-efficiency water reducing agents (PCE).
Polycarboxylate based high-performance water reducer (PCE) is currently the world's most cutting-edge, technologically advanced, with the best application prospects and comprehensive performance as a concrete water reducer. Polycarboxylate based high-performance water reducer is a composite product of carboxylic acid grafted copolymers and other effective additives. Comparison with similar products at home and abroad shows that polycarboxylate high-performance water reducers have reached the current international advanced level in terms of technical performance indicators and cost-effectiveness.
Polycarboxylate based high-performance water reducing agent (PCE) is a type of polymer compound mainly composed of acrylic acid and polyether monomers (MPEG, APEG, TPEG, HPEG, VPEG, etc.), which are copolymerized by water phase free radicals. It presents a comb like structure with acrylic acid as the main chain and polyether monomers as the branch chains. Its main properties such as water reduction rate and collapse resistance are closely related to the length and density of the main branches. Therefore, the molecular structure design has strong autonomy and flexible and diverse functional adjustments, which can meet the diverse needs of the market. And the molecular structure does not contain benzene rings, making it a green and environmentally friendly product.
Due to the fact that polycarboxylate superplasticizer (PCE) is a type of copolymer polymer product, and its performance is closely related to the length of the main branch, a certain proportion of chain transfer agent needs to be added to the entire copolymer system to adjust the molecular structure of the final product, with an addition ratio generally around 1 ‰. The factors to be considered in the selection of chain transfer agents mainly include transfer efficiency, price, dosage, availability, stability, feeding convenience, and hazard level.
At present, the chain transfer agents used in carboxylic acid based high-performance water reducers (PCEs) in the market are mainly 3-mercaptopropionic acid (MPA) and mercaptoacetic acid (TGA)
In recent years, the excessive demand for carboxylic acid based high-performance water reducing agents (PCE) and overheated investment have also brought about an excess supply. The price competition among enterprises has become increasingly fierce, and their profit margins have continued to decline. Therefore, a new round of technological transformation competition has emerged, actively seeking new processes and materials, and seeking differentiated business paths, which is currently the dominant trend in the market. As a result, some cost-effective related materials are gaining favor in the market. And 2-mercaptoethanol (2ME) is such a cost-effective alternative to chain transfer agents.
Comparison of advantages and disadvantages of various chain transfer agents
Advantages and disadvantages of chain transfer agents
Thioglycolic acid (TGA) has a moderate price, high water reduction rate, high chain transfer activity, high sensitivity to formulation systems, large content fluctuations, and difficult to control feeding amounts.
3-mercaptopropionic acid (MPA) has mild chain transfer activity, low sensitivity to formulation systems, and high slump retention. In winter, it is easy to crystallize and the feeding is inconvenient, resulting in high prices.
2-mercaptoethanol (2ME) is downgraded in hazard level and has a low price. High chain transfer activity, high sensitivity to formulation systems, and high odor and toxicity.
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