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A novel formula of anionic surfactants with propoxy (PO) and ethoxy(EO) groups and cationic surfactants was developed and temperature and salt resistance performance of the formula has been studied with both model oil and crude oil. An obvious synergistic effect was evidenced by CMC values and interaction parameters of nonylphenol polyether carboxylate, hexadecyltrimethylammonium chloride and their mixtures. Effect of molar ratio of anionic surfactant and cationic surfactant, temperature, salinity, concentration and oil-water ratio on phase behavior and interfacial tension were investigated systematically. The results demonstrate that ultra-low interfacial tension and excellent phase behavior were obtained at temperature up to 120 °C and a wide range of salinity, which shows promising for enhanced oil recovery.

Different tougheners including methyl methacrylate-butadiene-styrene terpolymer (MBS, core-shell type), maleic anhydride (MAH) grafted ethylene-octene copolymer (EOM), and MAH grafted polyethylene wax (PEM) were investigated for toughening the polycarbonate (PC) composites reinforced by short carbon fiber (SCF) and flake graphene (FG). The effects of tougheners on the preparation, thermal conductivity and mechanical properties of PC composites were studied. Scanning electron microscopy was used for characterizing the impact fracture surfaces of the composites. The results showed that introducing tougheners into the carbon reinforced PC composites was beneficial to improving the processability, and PEM was more effective than EOM and MBS. Meanwhile, the through-thickness and the in-plan thermal conductivity decreased to some degree due to the isolated island effects of tougheners. Moreover, the brittle PC composites with high flexural stress could be easily toughened by tougheners. In contrast, PEM had better toughening function than EOM and MBS, and correspondingly, the stiffness of the composites was the lowest for the PEM toughened systems. The fractography revealed that dense and uniformly distributed carbon fillers dispersed in matrix PC and circular cavities coexisted in the composites. The naked fiber length gradually increased as the ductility of composite materials improved.

Bio-based zwitterionic surfactants have received increasing attention owing to their structural diversity and good interfacial activity. Therefore, understanding the relationship between the structure of bio-based zwitterionic surfactants and interfacial behaviors has significance for its industrial applications. In this study, molecular dynamics simulation was employed to investigate the interfacial behaviors of bio-based zwitterionic surfactants (BZS) with seven structures at the air/water interface. The four of them were isomers of BZS, in which the phenyl groups were located at the 7-, 10-, 13-, and 16- carbon atom of the octadecanoyl group. The other three were the homologues of 10B, and were different in the structures of hydrophilic groups. The structure-property relationship was demonstrated by the structure of surfactant monolayer, the overall arrangement of surfactant molecules at the interface, and the dynamic properties of binding pairs between surfactant and water/cations. The results showed that waved monolayers were formed when the phenyl group located at the 7- carbon atom of the hydrophobic tail of BZS, and there were more hydration water and cations surrounding the hydrophilic group of surfactants. As for the surfactants with the phenyl group located at 16- of the hydrophobic tail of BZS, molecules were arranged more perpendicular at the interface and formed a flat monolayer and construct stable binding pairs with water and cations. Morphology of monolayer and molecular orientation were independent of the change in structure of headgroup, but surfactant with less methylene on the hydrophilic group had the less steric hindrance, which induced more hydration water, more neighboring surfactants, and more stable of binding pairs between COO- and water.

A novel binary system consisting of a cationic surfactant and a counter ion that can form wormlike micelles with high viscosity is proposed. Wormlike micelles based on 2-hydroxyethyl dimethyl hexadecyl ammonium acetate (HDMHA) and sodium salicylate (NaSal) as counter ion were detected via both cryo-TEM and SANS in dilute solution. Moreover, rheological measurements of the HDMHA/NaSal system were conducted as a function of temperatures. The results demonstrate the formation of long elongated wormlike micelles in dilute solution at temperatures that exceed 60 °C.

The surfactant structure–performance relationship and application properties in enhanced oil recovery (EOR) for binary mixtures of anionic and cationic surfactants are presented and discussed. A polyoxyethylene ether carboxylate anionic surfactant was blended with a quaternary ammonium chloride cationic surfactant and tested for a high-temperature, low-salinity, and high-hardness condition as found in an oil reservoir. These mixtures were tailored by phase behavior tests to form optimal microemulsions with normal octane (n-C8) and crude oil having an API gravity of 48.05°. The ethoxy number of the polyoxyethylene carboxylate anionic surfactant and the chain length of the cationic surfactant were tuned to find an optimal surfactant blend. Interfacial tensions with n-C8 and with crude oil were measured. Synergism between anionic and cationic surfactants was indicated by surface tension measurement, CMC determination, calculation of surface excess concentrations and area per molecule of individual surfactants and their mixtures. Molecular interactions of anionic and cationic surfactants in mixed monolayers and aggregates were calculated by using regular solution theory to find molecular interaction parameters β σ and β M . Morphologies of surfactant solutions were studied by cryogenic TEM. The use of binary mixtures of anionic/cationic surfactants significantly broadens the scope of application for conventional chemical EOR methods.

The effect of cellulose acetate butyrate (CAB) on the crystallization kinetics of polylactic acid (PLA) has been investigated by means of differential scanning calorimetry (DSC), polarized optical microscopy (POM) and scanning electron microscopy (SEM). CAB is essentially immiscible with PLA, as CAB spherical particles with average diameters in the range of 140–185 nm dispersed uniformly in PLA matrix. The incorporation of CAB effectively reduces the crystallization rate of PLA even at a low loading of 0.2 wt%. Moreover, it is particularly interesting to find a critical CAB content (about 5 wt%) which further increase in CAB concentration doesn’t bring significant influence on the PLA crystallization rate. Combined with the results of POM, SEM, DSC and selective dissolving experiment, it is proposed that the coating of CAB on the nuclei which enhanced by the nano-scaled CAB structure could strongly inhibit the nucleation, and thereby reduce the overall crystallization rates of PLA.

Heat- and salt-resistant amphiprotic polyacrylamide microsphere (APMS) was synthesized using inverse microemulsion polymerization method. The microstructure, swellability, filtration, and core flooding performances were tested and characterized. FT-IR spectroscopy indicates that APMS was successfully prepared. Morphological analysis reveals that it is relatively uniform and spherical with an average diameter about 50 nm. Its average diameter increases up to 634 nm after aging at 90°C for 7 days in synthetic brine. After aging for 30 days, the particle size is decreased to 482 nm. But the swelling magnification is still 9.6 times its initial diameter. Compared with the traditional microspheres, APMS exhibits excellent thermal stability, salt resistance, and swelling properties. In addition, the plugging factor is in the range of 0.236 to 0.317, and the number of particles for bridge-plugging is slightly increased from 2 to 4 over aging time. Moreover, the plugging parameters show that APMS can favorably enter and effectively plug the artificial cores with permeability of 0.19 to 0.50 µm2 by deformation, breakthrough and migration, bridging and plugging mechanisms. Furthermore, APMS also shows well its resistance to water flushing and good plugging strength in continuous injection experiment. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43366.

Sn–Nb2O5/α-Al2O3 catalysts were prepared by impregnation and tested for ethylene oxide (EO) hydration to form ethylene glycol. The effect of the calcination temperature on the structure, acidity, H2O and EO adsorption properties and catalytic performance of the catalyst were investigated by using XRD, TG-DTA, IR, NH3-TPD and EO-TPD. It was found that the phase compositions, acidity, the EO adsorption strength and water adsorption capacity of the Sn–Nb2O5/α-Al2O3 catalyst were markedly influenced by the calcination temperature. The catalyst calcined at a temperature between 350 and 400 °C showed the best catalytic performance. A correlation between catalytic performance and characterization was proposed.

The effect of tin on the structure, acidity, and water adsorption property of Nb2O5/α-Al2O3 catalyst and on this catalyst's performance for ethylene oxide (EO) hydration were studied by XRD, Raman spectroscopy, NH3-TPD, IR of pyridine and of H2O adsorption, and catalytic tests. Characterization results revealed that the density of acidic sites decreased with the addition of tin and with increasing Sn/Nb ratio in the cases studied, whereas the acidity exhibited minimum strength at Sn/Nb=0.08Sn/Nb=0.08. The IR of water adsorption indicated that addition of tin significantly enhanced the water adsorption property of the catalyst. The catalytic tests revealed that monoethylene glycol (MEG) selectivity increased from 89.8% of the Nb2O5/α-Al2O3 catalyst to 94.0% of the tin-promoted catalyst maintaining the EO conversion at 99.7%, and the catalyst exhibited excellent stability. The enhanced water adsorption property of the tin-promoted catalyst is proposed to be responsible for the significant improvement in MEG selectivity.

Effect of MgAl 2 O 4 on the structure, acidity as well as the catalytic performance of Nb 2 O 5 /α-Al 2 O 3 catalyst for ethylene oxide hydration was studied using IR, XRD, NH 3 -TPD, CO 2 -TPD and catalytic reaction. Modification of α-Al 2 O 3 support with MgAl 2 O 4 led to an increase in both basicity and mechanical strength of the support. As a result, the density and strength of the acidity of the niobium oxide catalyst supported on the MgAl 2 O 4 modified α-Al 2 O 3 reduced in comparison with that supported on the pure α-Al 2 O 3 . The acidity of 10% Nb 2 O 5 /MgAl 2 O 4 /α-Al 2 O 3 decreased with increasing loading of MgAl 2 O 4 . Catalytic test showed that EO conversion decreased monotonously with increasing MgAl 2 O 4 loading, whereas the selectivity to MEG exhibited a maximum of 90.6% at MgAl 2 O 4 loading of 2.23%. In terms of MEG yield, optimal MgAl 2 O 4 loading should be around 2%. Durability test demonstrated that 10% Nb 2 O 5 /MgAl 2 O 4 /α-Al 2 O 3 catalyst exhibited excellent stability within 1000 h time-on-stream.

Niobium oxide (Nb2O5) supported on α-alumina (α-Al2O3) prepared by impregnation was studied for hydration of ethylene oxide. The effects of niobium oxide loadings, calcination temperature and molar ratio of water to ethylene oxide (EO) on the reaction performance were investigated. The structure and acidity of the catalysts were characterized by using X-ray diffraction (XRD), differential thermal analysis (DTA)-thermogravimetric (TG) and infrared (IR) of pyridine adsorption. A durability test of niobic acid and Nb2O5/α-Al2O3 catalyst was carried out over a period of 1000 h. It was found that Nb2O5/α-Al2O3 demonstrated very high activity and selectivity for hydration of ethylene oxide to monoethylene glycol (MEG) under mild conditions. Compared with the result of non-catalytic reactions, the conversion of ethylene oxide was increased from 34 to 99.8% on keeping monoethylene glycol selectivity almost unchanged when the hydration was carried out over 10 wt.%Nb2O5/α-Al2O3 catalyst. The yield of monoethylene glycol over Nb2O5/α-Al2O3 was higher than that obtained over other solid acid catalysts. Moreover, the supported niobia catalyst demonstrated excellent stability and no deactivation was observed within 1000 h of time-on-stream.

Ethylene glycol was prepared by hydration of ethylene oxide over highly efficient supported niobia catalyst prepared by chemical vapor deposition. The catalyst showed much better hydration performance in activity and selectivity than other solid acid catalysts. An ethylene glycol yield of 91% was achieved at optimal conditions.