A series of thermally stable poly(arylene ether ketone)s (PAEKs) bearing benzimidazole structure in the main chains, named poly(arylene ether ketone-benzimidazole)s (PAEK-BIs), were directly synthesized by polycondensation of dimethyl bisphenol, dibenzimidazole bisphenol, and difluorobenzophenones. By systematically varying the amount ratio of two kind of bisphenols, the content of benzimidazole moiety in the backbone was controlled straightforwardly. The prepared amorphous polymers were characterized in terms of Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, thermal, dielectric, and gas transport properties. Evaluation of solubility reveals that PAEK-BIs with >60% content of benzimidazole units could be soluble in commonly used organic solvents. Also polymers containing content-tunable benzimidazole show high glass-transition temperatures (T_g's, 157–319°C) and excellent thermal stability (e.g., temperature of 5% weight loss, above 438°C in air). Dielectric constants of PAEK-BIs measured at 25°C are all less than 2.66 in the frequency range of 0.1–50 kHz. For dense films, the ideal gas selectivity and permeability coefficients could be compared with that of commercial Ultem 1000 membrane, which indicate that the PAEK-BIs are potential to be used for gas separation membrane material. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41289.

This work described a general strategy to enhance a typical organic–aqueous heterogeneous green oxidation reaction by introducing surface tunable magnetic nanoparticles into liquids to form a controllable Pickering emulsion. We synthesized cross-linked polystyrene (PS)-covered Fe₃O₄ nanoparticles grafted with different N-alkyl imidazoles and systematically discussed the effect of surface properties on the formation of emulsions. By loading such particles, the dichloromethane–water-based 2,2,6,6-tetramethylpiperidine-1-oxyl-mediated Montanari oxidation system was converted from the unstable millimeter-scale dispersion into a stable micrometer-scale emulsion, which significantly reduced the reactant transfer distance and resulted in a significantly high overall reaction rate. This reaction efficiency is elucidated in terms of unique properties inherent in an emulsion, including the self-assembly of Fe₃O₄/PS and Fe₃O₄/PS[im-C_n]Cl (n=1, 4, 6, and 10) nanoparticles, well ensuring a large specific surface area of the water–oil interface.

This study demonstrated the use of a magnetic superhydrophobic polymer nanosphere cage derived from a Pickering emulsion as a framework for miceller catalysis in biphasic media. We designed this system through the covalent stabilisation of active site (2,2,6,6-tetramethylpiperidine 1-oxyl)-grafted amphiphiles onto the magnetic hydrophobic core to form a micelle-like architecture and used it as a Pickering emulsifier to develop a new kind of micelle-catalysed biphasic system. The catalysis results reveal that these fixed micelle-tethered 2,2,6,6-tetramethylpiperidine 1-oxyl catalysts demonstrate much higher activity than their soluble counterparts in the biphasic Montanari oxidation of alcohols, which could be due to the unique properties of Pickering emulsion and miceller catalysis. In addition, the excellent magnetic response ensures the efficient recycling of the catalyst by magnetic decantation. The catalyst can be recycled at least 10 times without significant loss of activity or degradation of magnetic susceptibility. Moreover, this study demonstrates that this new Pickering emulsion-based and micelle-catalysed biphasic system is technically simple and practically applicable.

The 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical immobilized on the magnetic polystyrene nanospheres (MPNs) was used as a recyclable catalyst in the oxidation of various alcohols. The new and simply prepared heterogeneous TEMPO/MPNs exhibits both similar versatility and efficiency to homogeneous TEMPO under basic Montanari conditions. The excellent stability of the MPNs enables the TEMPO/MPNs to be recycled more than 20 times without significant leaching of immobilized TEMPO radicals or degradation of Fe₃O₄ nanoparticles. Moreover, the magnetic response ensures the rapid separation and quantitative recycling of TEMPO/MPNs by simple magnetic decantation.

A novel alternating copolymer of sulfonated poly(ether ether ketone-alt-benzimidazole)s (SPEEK-alt-BI) was synthesized by polycondensation in our previous report. In this article, we examined the properties of SPEEK-alt-BI membranes, such as thermal and mechanical stability, hydrolysis, and swelling properties in water, and proton conductivities at various temperatures and humidity. The experimental results showed that SPEEK-alt-BI membranes exhibited promising oxidative and hydrolysis stabilities. Although the base moieties in SPEEK-alt-BI main chain would capture proton and form reversible salt hindering the proton transfer capability, the conductivity of membrane 60SPEEK-alt-BI-H [Sulfonation degree (S.D.), 60% in form of proton] could achieve 22.61 mS/cm at 80°C and 100% humidity. Meanwhile, the conductivity of membrane could reach 40.12 mS/cm with phosphorus acid doping. The methanol permeation coefficient of 60SPEEK-alt-BI membrane is 2.3 × 10⁻⁸ cm²/s at 20°C, which is magnitude lower than that of Nafion®117, 1.11 × 10⁻⁶ cm²/s. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

The phase-separation behavior of high-density polyethylene (HDPE)/diluent blends was monitored with a torque variation method (TVM). The torque variation of the molten blends was recorded with a rheometer. It was verified that TVM is an efficient way to detect the thermal phase behavior of a polymer–diluent system. Subsequently, polyethylene hollow-fiber membranes were fabricated from HDPE/dodecanol/soybean oil blends via thermally induced phase separation. Hollow-fiber membranes with a dense outer surface of spherulites were observed. Furthermore, the effects of the spinning temperature, air-gap distance, cold drawing, and HDPE content on the morphology and gas permeability of the resultant membranes were examined. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010