Research On Polymerization Kinetics Of Polycarboxylate Superplasticizer

So far,studies focused on the preparation process, the ratio of raw materials, mechanism and relationship between structure and performance of polycarboxylate superplasticizer are reported. Researches on the radical polymerization kinetics and polymer formation process during the preparation process are still in the primary stage, which restricts the development of the related basic theory and application technology of polycarboxylate superplasticizer. So the systematic study is urgent to be carried out.Aiming at the lack of current researches about polycarboxylate superplasticizer kinetics, studies on the basic problems of polycarboxylate superplasticizer radical copolymerization kinetics, the dynamic process and the variation changed with time of polycarboxylate superplasticizer structure formation during the copolymerization reaction were carried out. First, the effect of different test conditions on the accuracy of high performance liquid chromatography was researched. The suitable test methods and conditions of the instrument used was determined. Second, the polymerization rate under different polymerization conditions was investigated. The effect of different polymerization process conditions on the polymerization rate was explored by measuring the conversion rate curve of macromolecular monomer changing with time. The results showed that the polymerization rate increased with the amount of AA and APS increasing, the amount of HPEG decreasing and the temperature rising. The kinetic equation of polymerization reaction using APS as the initiator was established, and the polymerization reaction activation energy Ea calculated under this condition was 42.46×10-4 kJ/mol. The polymerization rate and molecular structure formation process under the typical conditions were also investigated at the same time, including the variation law of the polymer molecular weight, molecular weight distribution, the mean square radius and the side chain density of polymers with the reaction time.The structure formation progress of polycarboxylate superplasticizer was preliminary elucidated, which will lay the basis for better understanding the relationship between structure and properties and realizing the design of structure and properties of polycarboxylate superplasticizer. This study will provide the technical and theoretical guidance for the optimization of polycarboxylate superplasticizer actual production process and the upgrading of polycarboxylate superplasticizer product quality.