Reseach On Synthesis And Properties Of PAA-AMPS Polycarboxylate Ceramic Superplasticizer

Due to the designable molecular structure and good application properties,the study of polycarboxylate superplasticizer has been a research hot topic.However,the research of polycarboxylate superplasticizer in the field of ceramics is less than that in the cement.Therefore,the effect of the synthetic process of polycarboxylate superplasticizeron on the molecular parameters,and the application properties need to be further investigated.In this paper,the study focuses on the effect of synthesis process on the molecular parameters and the influence of molecular parameters on ceramic slurry fluidity and thixotropy.In this thesis,the polycarboxylate superplasticizers were synthesized through free radical copolymerization with acrylic acid(AA)and 2-acrylamide-2-methyl propane sulfonic acid(AMPS)in aqueous solution.The molecular parameters of the polycarboxylate superplasticizers were characterized by FTIR and GPC.The properties of polycarboxylate superplasticizers were evaluated by paste and thixotropy of the slurry.The results were revealed by Zeta potential,adsorption amount and adsorption layer thickness.The main results were shown as follows:1 、 Effect of synthetic process on the molecular parameters of polycarboxylate superplasticizers was studied.The monomer concentration and ratio,the quantitity of initiator and chain transfer agent,and polymerization temperature can affect the molecular weight and conversion rate of the monomers.The conversion rate is about 80%.2、The effect of molecular parameters on the application properties of polycarboxylate superplasticizers was studied.As the decrease of the molecular weight of PAA-AMPS,the adsorption capacity increases,the thickness of the absorption layer decrease,and the Zeta potential increases,leading to the better dispersing properties and lower thixotropic of the slurry.Moreover,as the increase of monomer ratio of n(AMPS):n(AA),the adsorption capacity decreases,the thickness of the absorption layer increase,and the Zeta potential decreases,leading to the better dispersing properties of the slurry.3、Comparisons of PAA-AMPS and industrial samples were studied.The self-made AB-3exhibited better dispersing properties and wider dispersing range than that of industrial samples(pc67 and sodium polyacrylate).4、The experimental results show that the superplasticizer can reach the best dispersing performance in the clay slurry system at pH of 6.A higher or a lower pH would undermine the dispersing property.And the optimal pH of different clay slurry dispersing system is not the same.The dispersion properties are becoming better with the decrease of the molecular weight of PAA-AMPS in different pH system.