Synthesis And Characterization Of Polycarboxylate Superplasticizer And Its Application In Cement And Kaolin Suspension

Polycarboxylate superplasticizers exhibit some excellent abilities of low dosage,high water reducing ratio, great freedom of molecular structure change and wide application. It can improve the workability of concrete, reduce the amount of mixing water, change the setting time of concrete, overcome the problem of fast slump loss of concrete, enhance the compressive strength of concrete and it has good application prospect.In this paper, a kind of polycarboxylate superplasticizer using isoamyl alcohol polyoxyethylene ether(TPEG) and other polymerizable monomers was synthesized by free radical polymerization. The structure of superplasticizer was characterized by Fourier transform infrared spectroscopy(FT-IR). The zeta potential of the cement particles incorporated polycarboxylate superplasticizer was measured by zeta potential instrument. The molecular weight and molecular weight distribution was characterized by gel permeation chromatography(GPC). The viscosity, rheological properties,dispersion properties of suspension incorporated polycarboxylate superplasticizer were studied by digital viscometer, rheometer and transmission electron miscoscopy(TEM).The conclusions could be summarized as follows.Firstly, the ratio of TPEG to AA, dosage of initiator, dosage of SMAS and temperature have a great influence on the performance of product. When the ratio of TPEG to AA is 1:4, the ratio of TPEG to SMAS is 1:0.6, the dosage of initiator is 6%of total mass of monomers and temperature is 80?, the product has the highest fluidity of cement paste. It is up to 285 mm.Secondly, the ratio of TPEG to AA, dosage of thiohydracrylic acid, dosage of ascorbic acid as deoxidizer, dropping time have a great influence on the performance of product. When the ratio of TPEG to AA is 1:4.16, ratio of TPEG to thiohydracrylic acid is 1:0.18, ratio of TPEG to ascorbic acid is 1:0.01 and dropping time is 1 h, the product has the highest fluidity of cement paste. It is up to 235 mm. By the cement compatibility test and concrete adaptation experiment, the performance of the prepared polycarboxylate superplasticizer has basically reached the effect of a foreign brand superplasticizer.Thirdly, polycarboxylic dispersant using isoamyl alcohol polyoxyethylene ether of low molecular weight with other polymerizable monomers was synthesized by freeradical polymerization. The study shows that it can be applied in ceramic field. The apparent viscosity was lowered from 1088 m Pa·s to 258 m Pa·s.