Penglun Zheng

Synthesis and properties of cross-linkable poly(arylene ether nitrile)s containing side propenyl groups

Cross-linkable poly(arylene ether nitrile)s containing side propenyl groups (DPEN) were synthesized through nucleophilic aromatic substitution polymerization from biphenol, 2,2′-diallylbisphenol A (DBA), and 2,6-dichlorobenzonitrile. The structures of resultant copolymers were characterized by Fourier transform infrared and proton nuclear magnetic resonance spectroscopies. The properties of copolymers were investigated by thermal (differential scanning calorimetry and thermogravimetric analysis) analysis, inherent viscosity measurements, and mechanical tests. The results showed that allyl groups rearranged into propenyl groups during the polymerization. The copolymers with increasing content of DBA had high glass transition temperatures ranging from 207°C to 169°C and good thermal and thermo-oxidative stability with the 5 wt% loss temperatures in the range of 511–423°C under nitrogen and 471–402°C in air atmospheres, respectively. They also exhibited good mechanical property with tensile strength of 105–79 MPa. Meanwhile, the cross-linking reaction was studied through heat treatment. The result showed that the properties of DPEN containing side propenyl groups changed obviously after heat treatment, due to the fact that the double bond of PEN can be readily cross-linked to form net-shape polymers at high temperature.

Sulfonated carbon nanotubes synergistically enhanced the proton conductivity of sulfonated polyarylene ether nitriles

The addition of a small amount of sulfonated multi-walled carbon nanotubes (3 wt%) to a sulfonated polyarylene ether nitriles (SPEN) proton exchange membrane using an acyl chloride method was proved to be an effective way to improve the mechanical behaviour and proton conductivity performance.

Sulfonated copoly(arylene ether nitriles) as proton exchange membrane with excellent mechanical and thermal properties

A series of sulfonated biphenol poly(arylene ether nitriles) (BP-SPEN) copolymers were synthesized by the nucleophilic aromatic substitution polymerization of 2,6-difluorobenzonitrile with different ratios of hydroquinonesulfonic acid potassium salt and biphenol in the presence of potassium carbonate. The composition and structures of the BP-SPEN copolymers were characterized by Fourier transform infrared spectroscopy. Thermal properties, mechanical properties, proton conductivity, and water uptake of copolymer membranes were also investigated. The results showed that they present high glass transition temperature ranging from 131°C to 180°C and good thermal stability with the 5% weight loss temperatures in the range of 284–287°C under nitrogen atmosphere. They also exhibited good mechanical property with the tensile strength in the range of 68–109 MPa in the dry state and 31–72 MPa in the wet state. Furthermore, these copolymer membranes exhibited good water uptake ranging from 8.8% to 39.9%. Thus, the membranes had good proton conductivities in the range of 1.09 × 10−5–1.54 × 10−3 S cm−1 at room temperature and 100% relative humidity. The influence of temperature on water uptakes, tensile strength, and proton conductivity was also investigated.

Electrospun fluorescent polyarylene ether nitrile nanofibrous mats and application as an adsorbent for Cu2+ removal

Polyarylene ether nitrile (PEN) nanofibrous mat was fabricated by using the electrospinning technique and activated by using NaOH solution. The adsorption capacity of the activated PEN nanofibrous mat was evaluated using Cu2+ as the model hazardous metal ions. The effects of the contact time and the initial concentration of Cu2+ solution (C0) on the adsorption capacity of the mat were investigated. The adsorption kinetics was better described by the pseudo-second order equation, and the adsorption isotherm was better fitted for the Langmuir equation. Furthermore, the nanofibrous mat possesses the potential of regeneration and reuse. All of the results in this paper show that the PEN nanofibers produced via the electrospinning technique have excellent adsorbent properties toward Cu2+ ions.

Cross-linked sulfonated poly(arylene ether nitrile)s with low swelling and high proton conductivity

A series of cross-linked composite membranes were prepared from sulfonated poly (arylene ether nitrile) (SPEN) and 2, 5-diaminobenzensulfonic acid (DABSA) via a direct cross-linking method aiming to obtain low-swelling and excellent proton conductivity membrane. This experiment had two advantages: expectant low-swelling in the extreme temperatureand excellent proton conductivity. Besides, all cross-linked membranes showed excellent thermal stability which exhibiting a temperature of initial decomposition about 250 °C. The membranes showed the IEC values varying from 1.449 to 1.675 mmol·g-1. The result suggested that the SPEN-DABSA membranes are potential candidates as PEM in DMFCs.