Poly(arylene ether)s with different molecular weights were synthesized via a two-step nucleophilic substitution polymerization by adjusting reaction parameters based on phenolphthalein (PHT) and decafluorobiphenyl (DFBP). The chemical structures and properties were identified by Fourier transform infrared, NMR, gel permeation chromatography, differential scanning calorimetry, thermogravimetric analysis, dynamic thermomechanical analysis (DMA), and so forth. The number-average molecular weight (M n ) of the resulting polymers was in the range of 23.0–49.3KDa. FPAEs (polyarylether including perfluorobiphenyl structure) were demonstrated to have outstanding thermo-resistance with 5% weight loss temperature of about 482–520°C (N 2 ) and high-glass transition temperature (about 240–250°C). FPAEs can be dissolved in conventional organic solvents, possessing excellent film-forming properties. The good mechanical properties of FPAEs were confirmed by the DMA data, with Young's modulus greater than 1.0 Gpa and modulus retention rate at 230°C >67%. FPAEs also showed good hydrophobicity and low-water absorption, in particular, FPAE-1 (FPAE-1-5 were the polycondensation products of PHT and DFBP, just the polymerization conditions were slightly modified) exhibited favorable dielectric properties: at 1 MHz, the dielectric constant and dielectric loss was 2.58 and 0.0053, respectively. Thus, FPAE-1 has broad prospective applications in microelectronic devices and communication technology.
Ao Nan Lai,Yi Zhi Zhuo,Chen Xiao Lin,Qiu Gen Zhang,Ai Mei Zhu,Mei Ling Ye,Qing Lin Liu
Two series of novel poly(arylene ether sulfone nitrile) (PESN) multiblock copolymers are synthesized to prepare anion exchange membranes (AEMs) for alkaline fuel cells. To study the effect of phenolphthalein groups on the structure and properties of the membranes, the ion groups facilitating the formation of ion clusters are selectively and densely located on the phenolphthalein-sulfone segments of one and on the bisphenol A-sulfone segments of the other. The morphology and structure of the membranes are observed by atomic force microscopy and small angle X-ray scattering. The phenolphthalein-containing type endows the AEMs with a much clearer and more-defined microphase-separated structure leading to the formation of much larger and more developed interconnected ion-transport channels. As a result, high hydroxide conductivity (in the range of 2.04–12.98 × 10−2 S cm−1 from 30 to 80 °C) and H2/O2 fuel cell performance (an open circuit voltage of 0.92 V and a maximum power density of 66.4 mW cm−2 at 60 °C) can be achieved. Furthermore, the phenolphthalein-containing AEMs also show higher water uptake and mechanical strength, lower swelling ratio, and higher thermal and alkaline stability than the phenolphthalein-free AEMs.
Lan Li,Jiangtao Liu,Guofei Chen,Lubo Xu,Nafeesa Mushtaq,Lala Rukh Sidra,Ruixin Wang,Xingzhong Fang
A series of cardo poly(ether sulfone imide)s (PESI-C) containing bulky phthalide groups were prepared via aromatic nucleophilic substitution reaction of phenolphthalein with 4,4′-difluorodiphenyl sulfone and 4,4′-bis(4-fluorophthalimido)diphenyl ether (BFPI). The glass transition temperatures and 5% weight loss temperatures in nitrogen of the resulting PESI-C increased from 258°C to 278°C and from 468°C to 495°C with increasing the content of imide moiety in the polymer chain, respectively. These PESI-C films were transparent and essentially colorless and exhibited good mechanical properties with tensile strengths of 91–124 MPa, elongations at break of 6.9–12.8%, and tensile moduli of 2.2–2.8 GPa, respectively. It is noted that the tensile strengths, elongations at break, and tensile moduli of PESI-C also increased with increasing the content of BFPI in the copolymerization, indicating that the properties could be adjusted by controlling the ratio of BFPI and 4,4′-difluorodiphenyl sulfone.
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