Research On Synthesis Of Polycarboxylic Acid Water Reducing Agent Under Low Temperature

With the rise of domestic building construction, application of Polycarboxylatesuperplasticizer in the concrete structure is more and more extensive. Its superior waterreducing performance in the concrete construction technique has improved a lot,however, its comprehensive performance, production process and economic benefit isstill worth us to explore.At present, the ordinary poly carboxylic acid high efficiencywater reducing agent synthesis temperature is higher, generally in70-90℃ormore,because of the high reaction temperature increases the difficulty in the control ofsynthesizing technology, so how to reduce the reaction temperature, a more reasonablecontrol of big party monomer reaction, improve the economic benefits of massproduction are the key points of this topic research. The differences in the raw materialsof modern concrete, also increase a lot more difficulty in the quality control of concretemixing content. It’s difficult to make concrete mixing to keep good workability andslump retention in a relatively short period of time. And low temperature synthesis ofpoly-carboxylic acid high efficiency water reducing agent can effectively reduce themixing material of concrete slump loss, make concrete mixing to have good workingperformance in a long time, also has good mechanical properties and good durability.This paper studies the low temperature synthesis of polycarboxylic acid waterreducing agent, and uses the single factor experiment method to determine the optimumsynthesis process and the best reaction ratio of raw materials. With methyl allylpolyoxyethylene ether (TPEG) acrylic acid (AA) anditaconic acid as the main rawmaterial, in the presence of initiator, low temperature synthesis of poly (carboxylic acidhigh efficiency water reducing agent, the best synthesis process for n (AA): n (itaconicacid): n (thioglycolic acid): n (TPEG)=0.5:0.06:0.006:1, m (initiator): m (TPEG)=0.20, reaction temperature for44, and the reaction time is4h.Under the condition of thesynthesis of low temperature type poly carboxylic acid high efficiency water reducingagent, to control the water cement ratio0.29,0.4%water reducing agent, the cement netfluidity test cement as adopted by the poor adaptability of chang ge cement, cementinitial flowability net can reach280mm, the fluidity of net cement slurry after1h is260mm, has good dispersion and dispersing stability.For further research on the performance of low temperature synthesis of poly-carboxylic acid high efficiency water reducing agent, the adaptive contrastexperiment was carried out from different manufacturers of cement. For samples ofdifferent cement4#13#all showed better adaptability to cement, cement has good initialdispersion and dispersion properties, its effect is better than that of lattice gonadorelinSP010-GC and Taiwan TJB-01products and contrast test show that concrete4#haverelatively good water reducing effect and comprehensive performance, the effect isobvious,13#next, SP010-GC of bounded TJB-01concrete water reducing andcomprehensive performance are a bit poor. Four kinds of poly (carboxylic acid highefficiency water reducing agent configuration of the mechanical properties ofconcreteshould be equivalent.By infrared spectrogram, the structure of functional group in the4#13#waterreducing agent, SP010-GC and TJB-01is very similar to each other.4#,13#, SP010-GC, TJB-01hydroxyl absorption vibrationpeak are equivalent.4kinds of synthesiswater reducing agent have high overallperformance.13#C-H vibration absorptionpeak is the strongest,which shows that the poly carboxylic acid of high efficiency waterreducing agent monomer conversion rate is highest.13#COOH stretching vibrationpeak is the strongest, COOH4#stretching vibration peak is after13#, SP010-GC andTJB-01COOH stretching vibration peak are a bit weak, these show that13#waterreducing effect is the best.13#C-O-C strongest vibration absorption peakillustratesthe monomer conversion is the best, the density of branch chain in the highest.Thehigher density of branched chain, the space steric effect, the dispersion stability arebetter. Four kinds of poly carboxylic acid high efficiency water reducing agenton themolecular structure with water reducing retarded and influential effect of carboxylicacid and hydroxy functional groups, which further evidence from the molecularstructure, the synthesis of water reducing agent have comprehensive functions.