Effect of Organo-montmorillonite on the Morphology and Aging Properties of Various Bitumens

Effect of organo-montmorillonite （OMMT） on the morphology and aging properties of various bitumens was studied. The morphology of the binders was characterized by atomic force microscopy （AFM）. The influence of OMMT on physical properties of the binders before and after long-term aging and ultraviolet （UV） aging was investigated. It was observed that the effect of OMMT on the morphology and aging properties of bitumens depended on the base bitumen. In one case, OMMT affected the dispersed phase in bitumen. In the other case, OMMT affected the bitumen matrix. In both cases, OMMT caused stiffening of the modified phase. Compared with modification of the dispersed phase, modification of the matrix phase showed an obvious improvement on the physical properties as well as the better UV aging properties of bitumens, which was opposite to the long-term aging result.

Synthesis and characterization of poly(bisphenol A diglycidyl adipate)/organo-montmorillonite composites

The incorporation of clay nanoplatelets into biodegradable polymers is considered to be one of the best combinations for developing environmentally-benign high-performance materials. We utilized organo-montmorillonite （OMMT） in ring-opening polymerization of bisphenol A diglycidyl ether and adipic acid to prepare biodegradable linear poly （ bisphenol A diglycidyl adipate ） / organomontmorillonite （PBA/OMMT） nanocomposites. The products were analyzed by XRD, TEM, 1H NMR, GPC, DSC and TGA. The results demonstrated that PBA/OMMT nanocomposites were successfully formed and sufficient for the ordinary heating process. OMMT was beneficial for the modification of PBA hydroxyl polyesters on branched rate and polydispersity.

Comparison of Effects of Different Organo-montmorillonites on PA 66 / Clay Nanocomposites

Different organo-montmorillonites （OMMTs） are prepared by modifying montmorillonites （MMTs） with CTAB, PA 1010 salts/CTAB, PEG/CTAB, PVA/CTAB, PVP, PVP/ CTAB and PA 6/CTAB, respectively. These OMMTs were studied by X-ray diffraction and TG. The gallery sizes of them are all larger than that of sodium MMTs. And the decomposition temperatures of them are all much higher than that of MMT and the processing temperature of PA 66, especially OM - 6 and OM - 7, the decomposition temperatures of which are 451.6℃ and 439.1℃, almost the collapse temperature of the native MMT crystal lattice which is more than 5080C. Then PA 66/Clay nanocomposites were synthesized by mixing these OMMTs with PA 66 matrix via melt intercalation. Experimental results indicate that the tensile and flexural properties increase significantly, especially those of PCN - 08. The combination property of PCN- 08 is the best. TEaM photos show that some clay platelets are present in the matrix as exfollated layers, while most of the clay platelets are present as intercalated layers.

A comparative study and evaluation of sulfamethoxazole adsorption onto organo-montmorillonites

Three organo-montmorillonites were prepared using surfactants, and their adsorption behaviors toward sulfamethoxazole（SMX） were investigated. The surfactants used were cetyltrimethyl ammonium bromide（CTMAB）, 3-（N,N-dimethylhexadecylammonio） propane sulfonate（HDAPS） and 1,3-bis（hexadecyldimethylammonio）-propane dibromide（BHDAP）. The properties of the organo-montmorillonites were characterized by X-ray diffraction, scanning electron microscopy and N2adsorption–desorption isotherm measurements. Results showed that the interlayer spacing of montmorillonite was increased and the surface area as well as the morphology were changed. Batch adsorption experiments showed that the surfactant loading amount had a great effect on the adsorption of SMX. The adsorption process was p H dependent and the maximum adsorption capacity was obtained at p H 3 for HDAPS-Mt, while CTMAB-Mt and BHDAP-Mt showed a high removal efficiency at 3–11. The adsorption capacity increased with the initial SMX concentration and contact time but decreased with increasing solution ionic strength.Kinetic data were best described by the pseudo second-order model. Equilibrium data were best represented by the Langmuir model, and the Freundlich constant（n） indicated a favorable adsorption process. The maximum adsorption capacity of SMX was 235.29 mg/g for CTMAB-Mt, 155.28 mg/g for HDAPS-Mt and 242.72 mg/g for BHDAP-Mt. Thermodynamic parameters were calculated to evaluate the spontaneity and endothermic or exothermic nature. The adsorption mechanism was found to be dominated by electrostatic interaction,while hydrophobic interaction played a secondary role.

Debromination of decabromodiphenyl ether by organo-montmorillonitesupported nanoscale zero-valent iron: Preparation, characterization and influence factors

An organo-montmorillonite-supported nanoscale zero-valent iron material （M-NZVI） was synthesized to degrade decabromodiphenyl ether （BDE-209）. The results showed that nanoscale zero-valent iron had good dispersion on organo-montmoriUonite and was present as a core-shell structure with a particle size range of nanoscale iron between 30-90 nm, characterized by XRD, SEM, TEM, XRF, ICP-AES, and XPS. The results of the degradation of BDE-209 by M-NZVI showed that the efficiency of M-NZVI in removing BDE-209 was much higher than that of NZVI. The efficiency of M-NZVI in removing BDE-209 decreased as the pH and the initial dissolved oxygen content of the reaction solution increased, but increased as the proportion of water in the reaction solution increased.

The Structure of Montmorillonites Modified with Zwitterionic Surfactants and Their Sorption Ability

In the past four decades, there is a growing use of surfactant modified clay complexes in wide range of applications. The mostly used surfactants to modify the swelling clay minerals are cationic surfactants, such as quaternary ammonium, which consists of two distinct moieties, a hydrophilic head, where the positive charge is concentrated, and a hydrophobic hydrocarbon chain tail. During the surface modification, this kind of surfactant molecules attach on the inner and outer surface of clay minerals, the hydrophilic surface of raw clay minerals may changed into hydrophobic surface. The changes of organophilicity and hydrophobicity of clay minerals enable them used in more wide fields, such as adsorbents for organic contaminant, geotechnical barriers, filling of nanocomposite, etc.

Clay Modification by the Use of Organic Cations

To render layered silicates miscible with polymer matrices, one must convert the normally hydrophilic silicate surface to an organophilic one, making the intercalation of polymeric chain between silicate layers possible. This can be done by ion-exchange reactions with cationic surfactants. Sodium montmorillonite (Na-MMT) was modified with several organic cationic surfactants. Organoclays with water soluble surfactants were prepared by the traditional cation exchange reaction. An alternative procedure was used to prepare organoclays with water insoluble salts. The basal spacing and thermal behavior of organoclays were characterized by X-ray diffraction, XRD and Thermogravimetric analysis, TGA respectively.