Preparation And Performance Of Poly(Acrylic Acid)/montmorillonite Functional Composites

In recent years,organic-inorganic nanocomposites have attracted greatinterests from scientists.This new type of composites exhibit properties far superior to those of separate components,which makes them widely used in many field.In this paper,our work includes five main parts:1.By high temperature rapid-induced solvent polymerization reaction between acrylic acid and montmorillonite as principal raw material,the superabsorbent nanocomposites were synthesized.The relationship between the reaction condition and the water-absorbing capacity of the superabsorbent composites were investigated,such as the amount of initiator,the amount of cross linker,neutralization degree,the temperature and the amount of montmorillonite.The SEM photographs of the nanocomposites show that the product possesses better absorbent function when the initiator concentration is 0.175%,the cross linker concentration is 0.225%,the neutralization degree is 70%,the temperature is 85℃and the montmorillonite concentration is 5%,the water-absorbing capacity of nanocomposites is 511 times of its weight.2.The effect of different contents of montmorillionite on the structure of nanocomposites was studied.The Fourier Transition Infrared(FTIR)analysis and X-ray Diffraction(XRD)characterization of nanocomposites suggest that the chains of polymer have been successfully intercalated into the galleries of MMT and the intensities of peaks have become weakened.The peaks turned into dispersed peaks, which mean that the poly(acrylic acid)/montmorillonite nanocomposite become the exfoliated nanocomposites.3.In the range of 20～70℃,the water-holding reaction with poly(acrylic acid)/montmorillonite nanocomposites were tested and studied.The results show that the whole water-lossing of 10 gram swollen particles almost needed 128 h at 20℃and the water-holding capacity of the nanocomposites is outstanding in high temperature and its water-absorbing process followed after the zero-order reaction,the reaction rate constant k=3.7967x10⁷exp(-Ea/RT)with the apparent activation energy Ea=43.19KJ/mol.4.In the range of 20～40℃,the adsorption behaviors of FeCl₃ and CuSO₄ in poly(acrylic acid)/montmorillonite nanocomposite was tested and studied.The adsorption behaviors of dilute solution of FeCl₃ with nanocomposite at room temperature was in accordance to Freundlish relationship with an equilibrium absorbing capacity ofΓ=5.31c^0.61g/g,and this adsorptional process followed after the two-order reaction with a linear relationship between 1/c and adsorptional time t. Reaction rate constant k=1.955×10^-6exp(26.025 KJ/RT)with the apparent energy Ea=-26.025KJ/moll;The adsorption behaviors of dilute solution of CuSO₄ with nanocomposite at room temperature was in accordance to Freundlish relationship with an equilibrium absorbing capacity ofΓ_e=2.15c^0.89g/g,and this adsorptional process followed after the one-order reaction with a linear relationship between In(c₀/c)and adsorptional time t.Reaction rate constant k=6.3359×10^-5exp(22.166 KJ/RT)with the apparent energy Ea=-22.166KJ/molKJ/moll;The adsorption of FeCl₃ and CuSO₄ with nanocomposite could perform quickly at lower temperature such as 20℃and was exothermic reaction.5.The degradation process of poly(acrylic acid)/montmorillonite/TiO₂ nanocomposite was studied.The Fourier Transition Infrared(FTIR)analysis suggested that the nanocomposite had a degradation reaction under the ultraviolet ray treatment. The nanocomposite is a new and a friendly environment material...