| Nano-attapulgite is a one-dimensional rod-like structure, covered with a large number of hydroxyl of its surface, which formed hydrogen bonds with the cyclodextrin and p-phenylenediamine, which strengthen and improve the structure and properties of the hydrogel. It does not swell in water, sticky when it is wet, good suspended in water, its rheology is influenced by cationic/anionic surfactant and Mg-Al-Fe-HT1c greatly; Nano-attapulgite also has rheology, adsorption, catalytic, bactericidal, deodorant and other characteristics, which widely used in colloidal mud, adsorbents, carrier, and environmental protection, water treatment and other aspects. The attapulgite is abundant and inexpensive in china, researching the basis performance of the attapulgite, expected widely used in industry and agriculture according to the different needs.This thesis using X-ray diffraction (XRD), Fourier transform infrared spectroscopy(FT-IR), scanning electron microscopy (SEM) and the rheological test research the attapulgite influence for the structure and properties of the hydrogel. Using a rheological method to test the nano-attapulgite suspended liquid rheology, which influenced by cation/anion surface active agent, Mg-Al-Fe Hydrotalcite, pH values. The main content is as follows:1,The complicated hydrogels were made from nanosized palgorskite, α-cyclodextrin (α-CD) and PEO137-b-PPO44-b-PEO137(EPE). The structure and properties of the complicated hydrogels were characterised with techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning Electron microscopy (SEM) and rheometer. Experimental results showed that the addition of proper amount of nanosized palgorskite did not destroy the characteristic "channel-type" crystallinity of PEO/α-CD polyrotaxanes. When the amount of the nanosized palgorskite was less than2.5%, the continuity, thickness and porosity of the hydrogel network structure could be improved. With increasing the content of nanosized palgorskite, the hydrogel gel time was reduced, but the rigidity and the mechanical strength of the composite hydrogel were enhanced.2,The composite hydrogel of p-phenylenediamine modified nano-attapulgite/polyacrylic acid was successfully fabricated at room temperature. The influences of modified temperature and time, modified mass ratio of p-phenylenediamine and nanosized attapulgite, amount of modified nano-attapulgite and polyacrylic acid on gelation time were investigateded, and the composite hydrogels were characterized with techniques such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and rheological measurements. Experimental results showed that the dispersion of nano-attapulgite could be improved through modified with p-phenylenediamine, and the composite hydrogel of p-phenylenediamine modified nano-attapulgite/polyacrylic acid had shortened gelation time. Rheological tests showed that the viscosity, rigidity and mechanical strength of the composite hydrogel were increased with the concentration of modified nano-attapulgite in range of3.0%~7.0%. As for the influence of concentration of polypacrylic acid, the viscosity, rigidity and mechanical strength of the composite hydrogel were increased in the range of1.0%~2.0%, but decreased gradually in the range of2.0%~3.0%.3,In pure attapulgite suspension system, with increase in concentration of attapulgite, in the same shear rate, the shear stress and the viscosity increased. When the concentration of attapulgite is bellow than10%, the system has a small thixotropy. When adding2%of the benzimidazole in the same concentration of attapulgite of pure attapulgite system, in the same shear rate, shear stress and viscosity increased. When adding2%sodium dodecyl sulfate in the same concentration of attapulgite of pure attapulgite system, in the same shear rate, shear stress and viscosity decreased. The impact of pH for the suspension was studied and found that when the pH value is more close to the value of the attapulgite system, in the same shear rate, the shear stress and viscosity are larger. When Increased the pre-shear rate or extend the pre-shearing time, would make the initial viscosity and shear stress of the suspension system are reduced.4,The rheological property of the suspension consisting of Magnesium-Aluminum-Iron Hydrotalcite-like compounds (Mg-Al-Fe-HT1c) possesing permanent positive charges and Attapulgite (APT) possesing permanent negative charges was studied. The results show that the pure APT suspension with content of APT>2%and the Mg-Al-Fe-HTlc/APT suspension are not Newton fluid. When the molar ratio n(Mg):n(Al):n(Fe)=5:1:1, plastic soil ratio R=0.2, or the molar ratio n(Mg):n(Al):n(Fe)=3:0.7:0.3, plastic soil ratio R=0.3, the positive charges and the negative charges are offset in the Mg-Al-Fe-HTlc/APT suspension, the repulsion becomes smaller, in the same shear rate, the sher stress becomes large; When the molar ratio n(Mg):n(Al):n(Fe)=5:1:1, When the molar ratio is constant, with the continued increase in nano-attapulgite, for the Mg-Al-Fe-HT1c/APT suspension, in the same shear rate, the shear stress become belower; When the molar ratio n(Mg):n(Al):n(Fe)=3:0.7:0.3, with the continued increase in R, the positive charges and the negative charges are offset the required content of APT is1.00%. The effects of different pH values for Mg-Al-Fe-HTlc/APT suspension is also researched, as the pH increases, in the same shear rate, the shear stress become belower. |
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