Synthesis and Compounding Technology of Polycarboxylate High Performance Water Reducer

Synthesis of polycarboxylate high-performance water reducer

1.Synthesis of Polyether Macromonomer

2.Synthesis process of new polyether polycarboxylate superplasticizer

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Compounding technology of polycarboxylate superplasticizer

1.?Compounding of polycarboxylate superplasticizer mother liquor

The compounding of the mother liquor can adjust the molecular side chain density of the product, and learn from each other. The diversification of product design is the basis for a good compounding, and the mother liquor with special properties can also be introduced to improve the quality. For example, introduce a mother solution with good slump retention, or introduce a slow-release slump retention agent. When the cost needs to be reduced, the introduction of economical polycarboxylate superplasticizer can be used. Some of the compounding of the mother liquor is the weighted average of the properties, and some can obtain the superposition effect of 1+1>2. For effects that cannot be achieved by a single mother liquor, perhaps a combination of multiple mother liquors can play the desired role.

2.?Compounding of functional components of polycarboxylate superplasticizer products

In order to effectively improve the performance of freshly mixed concrete and obtain polycarboxylate superplasticizer products suitable for on-site concrete use, in addition to the synthesis process of mother liquor, it is also necessary to add some functional components for simple physical compounding to improve the concrete. Retarding, air content, workability, appearance and other construction properties.

The physical compounding of retarder is indispensable. Adding retarding components is an important component to adjust the setting time of the admixture to adapt to different temperatures. Under permitted conditions, one or more retarders can be used together (commonly used are sodium gluconate, citric acid, phosphate, sugar , lignosulfonate, etc.), especially sodium gluconate and sugars have better adaptability. The amount of setting retarder is adjusted with the temperature, and the effect of adding sodium gluconate is better. Sometimes adding some retarder is beneficial to reduce slump loss, but it cannot be used as a more effective method to inhibit slump loss. When compounding retarders, many retarding components have a certain water-reducing effect, which should be considered in the amount of mother liquor and cost calculation.

Adding air-entraining agent is an effective method to increase the air content of concrete and improve the bleeding and viscosity of concrete. It requires the joint action of air-entraining agent and defoamer, and the two often need to go together. At present, there are many types of defoamers and air-entraining agents. It is best to conduct a compatibility test with polycarboxylate admixtures. First, the storage stability of polycarboxylate superplasticizer products must be solved. Commonly used air-entraining agents are fatty alcohol sulfonates, alkyl sulfonates, sodium alkenyl sulfonates, rosin resins, etc. The air content of the concrete needs to be appropriate. Although the concrete with too much air content is soft and easy to handle, it is easy to cause a decrease in strength.

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Bleeding of concrete is a common problem. It often causes concrete to separate and block the pump due to bleeding. There is laitance on the surface of the concrete, and defects of quicksand and water marks appear, especially when the bleeding occurs about 2 hours after concrete pouring. The method to control concrete bleeding is to add high-quality air-entraining agent and its dosage. A better method is to adjust the sand rate and increase the fine powder. Carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose), biological glue, etc., and pay attention to determine the appropriate molecular weight and dosage through experiments to prevent side effects caused by improper or excessive use.

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The synthesis and application technology of polycarboxylate-based high-performance water reducers has developed rapidly, and polyether-type polycarboxylate water-reducers have become the main varieties. Practice has proved that the serialization of polyether-type polycarboxylate water-reducers Agent products have been able to meet different needs very well.

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