The Study On Dispersion, Rheology And Curing Process Of Fly Ash Based Sealing Coating

With the development of our society,some special projects need sealing materials to seal the gaps or walls of the project,so as to improve the safety level.With the continuous development of sealing materials,polymer cement type sealing coating has the safety and environmental protection characteristics of water-based coating,and has become the main research direction because of its excellent sealing performance.In this paper,ultrafine fly ash and flame retardant components are used as filler in the system of styrene acrylic emulsion cement composition.These organic/ inorganic particles with different properties constitute the coating suspension system.It is precisely because of the interaction of these components with different properties that the specific performance of the coating is achieved.In practical application,in order to prepare the coating that meets the requirements,it is necessary to study the curing mechanism of the sealing coating.Therefore,on the basis of previous studies,this paper makes a further detailed study,the research contents are as follows:(1)The effects of different amount of SHMP(sodium hexametaphosphate)on the dispersion and dispersion behavior of the fillers in the paint system were studied.It was found that when the concentration of SHMP was 0.2g/l,the system formed a good stability.In addition,the interaction among the three particles of carbon black,graphite and fly ash was calculated by the extended DLVO theory to analyze the dispersion mechanism.SHMP was not only used to analyze the dispersion mechanism.Through the strong negative charge PO3-group in the molecule,a double electric layer is formed between the particles,generating electrostatic repulsion force,and a certain thickness of adsorption layer is formed on the surface of the particles,increasing the space potential resistance,thus improving the stability of the system.(2)Three kinds of rheological additives were introduced into the sealing coating system to improve the coating delamination caused by the settlement of inorganic particles.Through the analysis of shear rate viscosity,yield force and dynamic mechanical test,the influence on the anti sinking and thickening effect of the system was compared.It was found that BYK-420,a 0.4g rheological regulator,was dispersed in the system to form a stable three-dimensional network with a yield force greater than 10 dyn / cm2 has the advantages of high thickening efficiency and obvious shear thinning characteristics.Meanwhile,it makes the system show better solid behavior and thixotropic performance,achieving the effect of anti sinking and avoiding sagging.(3)Through the analysis of FT-IR,SEM and conductivity meter,it is concluded that during the curing process of the coating,the polymer bond with the hydration products of cement and fly ash inside the coating through Ca2+,and the "bite" of organic and inorganic particles makes the system particles closer,improves the crosslinking network,and improves the coating compactness and sealing efficiency.Furthermore,the possible curing mechanism and model of the interface layer between the coating body and the coal substrate are proposed,and the impermeability of the coating after curing is tested by the impermeability tester.(4)The pilot test production line designed according to the two-component coating system participates in the production of the coating product,mainly including the installation of the production line equipment and the adjustment of the operation parameters.At the same time,according to the coating formula,the mixing and packaging of the coating powder and the mixing and packaging of the coating and the liquid are carried out,realizing the high combination of theory and practice,forming a research closed-loop.