Determination And Analysis Of Reactivity Ratio Of Two Kinds Of Ether Monomers With Acrylic Acid

Polycarboxylate Superplasticizer?PCEs?is called third-generation high-performance superplasticizer and is often used in various fields of construction engineering.They have excellent performance and environmental friendliness.With the rapid development of the polycarboxylate superplasticizer industry,the production and application of polyether macromonomers are rising.However,due to the lack of basic data such as the reactivity ratio of polyether type water-reducer comonomer,the performance of polycarboxylate superplasticizer can only be optimized by continuous exploratory experiments in the production process.In order to carry out the production practice better,it is necessary to study the reactivity of different ether macromonomers with the same small monomer in the copolymerization reaction.The research content of this paper is as follows:?1?The reactivity ratio is the size of the monomer entering the copolymer in the copolymerization system.The copolymerization behavior of the monomer can be visually analyzed by the size of the reactivity ratio,and the production practice can be guided.The commonly used methods for calculating the reactivity ratio include the FR method,the YBR method and the K-T method.The data results show that the FR method has a large error,and the average value of the YBR method and the K-T method can be used as the final result;?2?The ether macromonomer ethylene glycol monovinyl polyethylene glycol ether?EPEG?and the ether macromonomer prenol polyglycol ether?TPEG?reacts with the small monomer acrylic acid?AA?is copolymerized under suitable conditions to control the polymerization conversion rate below15%,by gel permeation chromatography and infrared spectroscopy The synthesized samples were characterized.The reactivity ratio was determinedby the FR method,the YBR method and the KT method.The calculation results showed that the copolymerization rate was r₁?EPEG?=0.00381,r₂?AA?=1.43366;r₁?TPEG?=0.00610,r₂?AA?=3.27080;?4?Comparing the activity of two ether macromonomers,it was found that the polymerization activity of EPEG was significantly greater than that of TPEG monomer,that is,the copolymerization capacity of EPEG and small monomer AA in the copolymerization system under the same conditions was better than that of TPEG and small monomer AA.And under different conditions,the time required for EPEG to polymerize with AA is shorter;?5?Comparing the activity of the two ether macromonomers,it was found that EPEG was much more active than TPEG under the same reaction conditions,and the copolymerization ability of EPEG and small monomer AA in the copolymerization system was stronger than that of TPEG and small monomer.The self-water-reducing agents EPEG-AA-PCEs and TPEG-AA-PCEs were synthesized at a monomer ratio of 2:8.The water-reducing agent samples were tested for homogeneity and concrete performance,including concrete slump,gas content,setting time and compressive strength.The test results show that the self-made PCEs perform well in all aspects,indicating that the performance of the homemade PCEs meets the performance standards of the commercially available water reducing agent.