Research On The Performance Of PB-g-PSG Latex Modified Cement Mortar

In this paper, a PB-g-PSG latex with core/shell was made using semi-continuous seed emulsion graft polymerization method, polybutadiene(PB) was synthesized with styrene(St) and glycidyl methacrylate(GMA) quality than50:46:4, and by joining the tween-20into PB-g-PSG latex to improve the stability of cement mortar. Finally, the PB-g-PSG latex modified cement mortar of sulfuric acid corrosion resistance was analyzed. The specific work contents and the obtained conclusions are as follows:Using redox initiator system of CHP-Fe2+, applying PB as seed emulsion, St and GMA as grafting monomer, a kind of PB-g-PSG latex was compounded by the method of semi-continuous emulsion polymerization.Tween-20was added to the PB-g-PSG latex, and the quantities are3%,5%and7%of solid quality of latex, and then three kinds of cement modifier were prepared. PB-g-PSG latex was used to modify cement mortar in the constant water-cement ratio of0.4. This study examines the effects of twain-20content and the polymer-cement ratios on the flow, compressive and flexural strength water retention ratio and water absorption rate of PB-g-PSG latex modified cement mortar. The study shows that the flow of modified mortar is increased with increasing twain-20content polymer-cement ratios. The three kinds of latex can markedly reduce capillary water absorption rate, and increase water retention ratios, The maximum is99.22%, and can marked in influences much on the mechanical properties of modified mortars. The compressive strength of PB-g-PSG are decreased with increasing P/C, and are lower than control mortar, and flexural strength of polymer modified mortars are increased with increasing P/C at P/C lower than10%, and are higher than control mortar. The maximum of flexural strength of latex-modified mortar are9.45MPa. Microstructure is studied by using SEM, and the bridge structure, the interpenetrating network structure and pores structure were observed. The structure change of all is helpful for the improvement of the performance of mortar. The action mechanism twain-20is analyzed, and was considered to be isolation effect of layers of water molecules. In conclusion, twain-20can be used as stabilizer PB-g-PSG latex.PB-g-PSG latex was used to modify cement mortar in the constant water-cement ratio of0.4and polymer-cement ratio of10%. As the erosion media with different concentrations of sulfuric acid solution, the corrosion resistance of PB-g-PSG latex modified cement mortar is studied in this paper. The experimental results show that the weight loss,the water absorption ratio and the compressive strength of samples of samples are gradually increased with the increase of acid concentration and immersing time, but the variations of PB-g-PSG latex modified cement mortar is relatively small. The structure of samples are studied by SEM, a relatively compact internal structure can be seen in PB-g-PSG latex modified cement mortar. The calcium hydroxide crystal structure of hexagonal flake was seen, and its number decrease with the increase of the concentration of sulfuric acid solution, to effectively improve interfacial structure. These structural changes are conducive to improve of the acid-resistance performance of the mortar.