The Preparation Of Ethers Polycarboxylate High Performance Superplasticizer

Polycarboxylate superplasticizer, with the advantages of low addition, highwater reduction, excellent slump retaining ability, has widely used in the railway,bridge and water conservancy project. Ethers polycarboxylate superplasticizer, as anew kind of water-reducing agent, has rarely existing literature. The issue iscommitted to the synthesis and property of the ethers polycarboxylatesuperplasticizer, with many advantages, such as one step synthesis, simple process,high purity of product, low cost. The topic research contents and the mainachievements are as follows:(1) Making the technical route of the experimental study. According to accesslots of literature and theoretical analysis, the conditions of the polymerizationprocess has determined, and then the best polymerization condition has beenrespectively studied on APEG, with different molecular weight. Moreover, we mixedAPEG of different molecular weight as ether monomer, the result showed that APEGmixed with different molecular weight could improve the polymerization activity ofthe lower monomer.(2) In the best polymerization process conditions, the initial cement pastefluidity of APEG700type ether polycarboxylate superplasticizer A-A was as high as271.00mm, the loss over time was5.50mm, the water reduction rate was up to25%,and the compressive strength of3d,7d,28d were respectively16.93MPa,1706MPa,24.49MPa. The initial cement paste fluidity of APEG1200type etherpolycarboxylate superplasticizer B-B was as high as266.50mm, the loss over timewas10.50mm, the water reduction rate was up to31%, and the compressive strengthof3d,7d,28d were respectively15.47MPa,17.90MPa,25.24MPa. The initialcement paste fluidity of APEG2400type ether polycarboxylate superplasticizer C-Cwas as high as264.00mm, the loss over time was7.50mm, the water reduction ratewas up to32%, and the compressive strength of3d,7d,28d were respectively21.39MPa,23.86MPa,33.12MPa. The results showed that APEG type etherpolycarboxylate superplasticizer had high rate of water reduction, high compressive strength, excellent dispersibility and dispersion retention ability.(3) The subject studied the modification of APEG2400and the preparation ofthe new monomer. First, we made APEG2400and phthlandione to esterify with thepurpose of introducing the carboxyl and ester, and then we made esterificationproduct, AA and AMPS to polymerize. The result showed the initial paste fluiditywas low, and the flowing retention ability over time was high. The topic used newOP-10as esterification raw materials, esterified with MAA to receive OP-MAAmonomer, and then polymerized with MAA and AMPS. The result showed theproduct had poor water solubility and dispersion performance.(4) The project researched the unsaturated monomer selectivity of modifiedTPEG2400. According to single factor experiments, we determined the bestpolymerization process, introduced the fourth monomer methacylate, and thendiscussed the dispersion ability and dispersion retention ability. In the conditions ofthe optimum process and the0.25%dosage, the initial fluidity of cement paste wasup to281.00mm, and the paste fluidity over time was up to277.00mm, withexcellent dispersibility and dispersion retention ability. The water reduction rate wasup to33%, and the compressive strength of3d,7d,28d were respectively13.02MPa,25.14MPa,33.51MPa.(5) By means of modern analytical instruments, such as IR, UV, SEM, theexperiment showed the molecular structure of high polymer and the process ofcement hydration. We determined its mortar performance, and studied the influenceof the dosage, pH, placed time on the performance of the water-reducing agent.What’s more, we explored the practical application of ethers superplasticizer fromthe amplification effect and experimental repeatability. The result showed that etherspolycarboxylate superplasticizer had superior performance, such as high rate ofwater reduction, good dispersion ability, high compressive strength. The pastefluidity enhanced with the extension of time, which was suitable to mass industrialproduction.