Exfoliated polypyrrole/montmorillonite (PPy/MMT) nanocomposites with flake-like structure were prepared by in situ chemical oxidation polymerization. Amphoteric polymer, (2-methacryloyloxyethyl) trimethyl ammonium chloride and methacrylate acid copolymer, was used to modify montmorillonite and a large amount of carboxyl acid was introduced on the surface of clay platelets which can play a ‘bridge’ role to combine PPy with clay. The adsorption of Cr(VI) on the PPy/MMT was highly pH-dependent and the adsorption kinetics followed the pseudo-second-order model. The Langmuir isothermal model well described the adsorption isotherm data, whiler the maximum adsorption capacity increased with the increase of temperature. Thermodynamic investigation indicated that the adsorption process is spontaneous, endothermic and marked with an increase in randomness at the adsorbent–liquid interface. The maximum adsorption capacity of the PPy/MMT composites for Cr(VI) was 166.7 mg/g. A desorption experiment showed PPy/MMT composites can be regenerated and reused for two consecutive cycles with no loss of their removal efficiency.

Polyaniline/sepiolite (PANI/sepiolite) nanofibers were prepared by in situ chemical oxidation polymerization in the presence of sepiolite. The effect of aniline/sepiolite weight ratio on the nanostructure of PANI/sepiolite composites was investigated by field-emission scanning electron microscopy. The adsorption of Cr(VI) onto the PANI/sepiolite nanofibers was highly dependent on pH values. The pseudo-second-order and Langmuir isothermal models can well describe the adsorption kinetics and adsorption isotherm, respectively. The maximum adsorption capacity of the PANI/sepiolite nanofibers for Cr(VI) was up to 206.6 mg/g at 25 °C and increased with the increase in temperature. Desorption experiments indicated that PANI/sepiolite can be regenerated and reused for two consecutive cycles with no loss of its removal efficiency. PANI/sepiolite nanofibers can be used as a highly efficient and economically viable adsorbent for Cr(VI) removal due to their excellent adsorption characteristics.

Exfoliated polyaniline/montmorillonite (PANI/MMT) composites with nanosheet structure were successfully prepared by in situ chemical oxidation polymerization with MMT platelets as the scaffold. Amphoteric polymer, (2-methacryloyloxyethyl)trimethyl ammonium chloride and methacrylate acid copolymer, was used to modify montmorillonite and a large number of carboxylic acids were introduced on the surface of the clay platelets, which can be used as a dopant of PANI and play a 'bridge' role to combine PANI with clay. Adsorption experiments were carried out to study the effects of pH, contact time, Cr(VI) concentration, adsorbent dose and temperature. The adsorption of Cr(VI) on the PANI/MMT was highly pH dependent and the adsorption kinetics followed a pseudo-second-order model. The Langmuir isothermal model described the adsorption isotherm data well and the maximum adsorption capacity increased with the increase in temperature. Thermodynamic investigation indicated that the adsorption process is spontaneous, endothermic and marked with an increase in randomness at the adsorbent - liquid interface. The maximum adsorption capacity of the PANI/MMT composites for Cr(VI) was 308.6 mg/g at 25 °C. The excellent adsorption characteristic of exfoliated PANI/MMT composites will render it a highly efficient and economically viable adsorbent for Cr(VI) removal.

Polypyrrole-sepiolite nanofibers were prepared by in situ chemical oxidation polymerization in the presence of sepiolite. The nanostructure of PPy-sepiolite nanofibers was confirmed by field-emission scanning electron microscopy. The adsorption of Cr(VI) onto the PPy-sepiolite nanofibers was highly pH dependent and the adsorption kinetics followed the pseudo-second-order model. The Langmuir isothermal model well described the adsorption isotherm data and the maximum adsorption capacity increased with the increase of temperature. The maximum adsorption capacity of the PPy-sepiolite nanofibers for Cr(VI) was up to 302 mg.g(-1) at 25 degrees C. Thermodynamic investigation indicated that the adsorption process is spontaneous and endothermic. Desorption experiment showed PPy-sepiolite can be regenerated and reused for four consecutive cycles without obvious loss of its removal efficiency. The excellent adsorption characteristic of PPy-sepiolite will render it a highly efficient and economically viable adsorbent for Cr(VI) removal.

Allyltriethylammonium was used to modify sodium based montmorillonite.Polystyrene/montmorillonite(PSt/MMT)nanocomposites have been synthesized by soap-free emulsion polymerization.The structures of the organo-montmorillonite and nanocomposite were characterized by Fourier transform infrared spectroscopy(FTIR),X-ray diffraction spectroscopy(XRD)and dynamic light scattering(DLS).FTIR and XRD results showed that the intercalation modification of MMT with the use of allyltriethylammonium bromide was successful,the interpass dspacing was increased from 1.32nm to 1.44nm after modification.PSt/MMT nanocomposites were successfully prepared with different MMT content(1%~5%)and had an exfoliated structure with the absence of d001 diffraction peak of MMT in the XRD region.DLS results showed that the diameter of composite latex particles was decreased with the increase of the MMT content.

In this study, flake-like polyaniline/montmorillonite (PANI/MMT) nanocomposites with rough surface were successfully prepared by in situ chemical oxidation polymerization during which poly(2-acrylamido-2-methylpropanesulfonic acid), a polymer acid, on the surface of clay platelets was used as dopant of PANI and played a 'bridge' role to combine PANI with clay. Flake thickness and surface roughness of PANI/MMT composites decreased with the increase of montmorillonite/aniline feeding ratio. The effects of operating parameters including pH, contact time, Cr(VI) concentration, and adsorbent dose were studied. The pseudo-second-order equation and three adsorption isotherms including Langmuir, Freundlich, and Temkin equations were applied to determine the adsorption rate and capacity. The results show that the flake-like PANI/MMT nanocomposites exhibited a high adsorption capacity (167.5 mg/g). The excellent adsorption characteristic of flake-like PANI/MMT nanocomposites will render it a highly efficient and economically viable adsorbent for Cr(VI) removal.

Organo-montmorillonite was obtained by using allyltriethylammonium bromide to modify sodium montmorillonite through cation exchanging reaction.Poly(methyl methacrylate)/montmorillonite(PMMA/MMT) nanocomposites were synthesized by soap-free emulsion polymerization using methyl methacrylate(MMA) as monomer and potassium persulfide as initiator.The structures of the organo-montmorillonite and nanocomposites were characterized with Fourier transform infrared spectroscopy(FTIR),X-ray diffraction spectroscopy(XRD) and scanning electron microscopy(SEM).The spacing increases from 1.32 nm to 1.44 nm after intercalation modification of MMT with the use of allyltriethylammonium bromide.FTIR and XRD results show that PMMA/ MMT nanocomposites with different MMT content have an exfoliated structure.SEM results show that the diameter of PMMA/MMT composite particles decreases with the increase of the MMT content.

Polystyrene/montmorillonite (PSt/MMT) nanocomposite latexes have been synthesized by soap-free emulsion polymerization using MMT clay platelets as stabilizer. Small amounts of methacrylic acid were used as auxiliary monomer to promote clay adhesion to the surface of the particles. Overall solids content of the composite latexes in complete absence of coagulation of up to 30.7 wt% are reported under batch conditions. The 3 wt% MMT clay platelets were sufficient to maintain the colloidal stability and increasing MMT clay content resulted in the increase of particle diameter due to the improved viscosity of reaction medium. Transmission electron microscopy results demonstrate the existence of MMT platelets on the particle surface. X-ray diffraction spectroscopy (XRD) results show that an exfoliated structure of PSt/MMT nanocomposites was obtained in this study with the absence of d(001) diffraction peak of MMT in the XRD region.

In comparison with soybeans in conventional storage,the change of soybean quality with time at different storage temperatures under controlled atmosphere storage with N2 was studied.The test shows that,under the same storage condition, the higher storage temperature results in the more remarkable quality deterioration of soybeans.Controlled atmosphere storage with N2 is better than conventional storage in keeping the storage quality of soybeans.Controlled atmosphere storage with N2 can effectively suppress the decrease of germination rate,watersoluble protein and nitrogen solubility index(NSI) and the increase of fat acid value,but has no great influence on the contents of crude fat and crude protein in soybeans.