Polydienyldimethylammonium Chloride Inhibits Swelling Mechanism Of Montmorillonite

The water swelling of the montmorillonite component in the sandstone is the mainreason for the water swelling and collapsing.In this paper,polydiallyl dimethyl ammonium chloride(PDDA)was used to inhibit the swelling of montmorillonite in slate sandstone.The inhibitory mechanism of polymer inhibitor PDDA on swelling of montmorillonite in sandstone was studied.Soil erosion in sandstone areas provides an effective method.First,the montmorillonite with higher taste is purified by sedimentation.Four kinds of polydiene dimethyl ammonium chloride polymer inhibitors with different molecular weights were used to inhibit swelling of montmorillonite.The effect of the molecular weight of PDDA on the hydration swelling of montmorillonite was explored by the linear swelling level of montmorillonite in the aqueous solution of the inhibitor,and the contrast between swelling inhibitory properties of inorganic salts and polymer inhibitors was explored,and the washing test was performed.Durability of the use of inhibitors.Secondly,the effect of K+,NH4+inorganic salt inhibitors and PDDA polymer inhibitors on the hydration,swelling,and dispersion of montmorillonite particles of montmorillonite/water suspensions was investigated by particle size analysis.Thirdly,the surface potential of montmorillonite after PDDA treatment was studied by Zeta potential measurement.The inhibition mechanism of PDDA solution on montmorillonite was analyzed by the change of potential.The effect of montmorillonite on the adsorption of PDDA was studied quantitatively by UV-Vis spectrophotometer.At the same time,the effect of adsorption time on the adsorption equilibrium was investigated and the adsorption isotherm was made.Finally,the montmorillonite treated by PDDA was characterized by XRD,TG/DTG,SEM and FTIR,and the surface morphology and interlaminar spacing of the treated montmorillonite particles were investigated.At the same time,the TG/DTG test can verify the results of the UV spectrophotometer research on the adsorption of PDDA on montmorillonite.It was found that PDDA has a significant inhibitory effect on the swelling of montmorillonite compared to inorganic salts,and the treated montmorillonite particles have a more concentrated distribution and larger particles.And the PDDA-treated montmorillonite is still strongly inhibited by washing with water,indicating that PDDA is firmly adsorbed on the surface of montmorillonite to form a protective film to prevent the entry of water molecules.In the treated montmorillonite,the surface potential goes from negative to zero potential.When montmorillonite is dispersed in PDDA solution,the adsorption of PDDA molecules by montmorillonite is well linear in the concentration of 0.1% to 0.5%.As the concentration increases,the amount of adsorption gradually expresses and eventually saturates..XRD results showed that the interplanar spacing of dry montmorillonite was 1.36 nm and 1.45 nm after hydration.After treatment with PDDA inhibitors,the montmorillonite spacing was 1.47 nm at a concentration of 0.1%.It shows that the PDDA inhibitor enters into the montmorillonite crystal layer.With the increase of inhibitor concentration,the interplanar spacing of montmorillonite gradually decreases.When the concentration is 1.5%,the interplanar spacing is 1.39 nm.Thermogravimetric results and infrared measurements also showed that montmorillonite treated with PDDA inhibitors had an inhibitory effect on the hydration of montmorillonite,and the free water content adsorbed by montmorillonite also decreased with increasing inhibitor concentration.The SEM results showed that the montmorillonite treated with PDDA improved its lamellar structure,causing smaller montmorillonite particles to agglomerate together to form large montmorillonite particles.In addition,PDDA inhibitors with larger molecular weight improve the pore structure between montmorillonite particles,which promotes the formation of a dense structure of montmorillonite,thereby reducing the entry of water molecules,and thus suppressing the swelling of montmorillonite.