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首页> 外文期刊>Journal of Applied Polymer Science >Dielectric relaxations in phosphoric acid-doped poly(2,5-benzimidazole) and its composite membranes
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Dielectric relaxations in phosphoric acid-doped poly(2,5-benzimidazole) and its composite membranes

机译：磷酸掺杂聚（2,5-苯并咪唑）及其复合膜的介电弛豫

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摘要

Poly(2,5-benzimidazole) (ABPBI)-a promising high-temperature polymer electrolyte membrane-is characterized over a wide range of temperature (-50 to 220 degrees C) using broadband dielectric spectroscopy (BDS) to understand the various relaxation processes. The undoped ABPBI membrane shows two major secondary relaxations and a primary relaxation. The effect of phosphoric acid (PA) and phosphotungstic acid grafted zirconium dioxide (PWA/ZrO2) nanoparticles on the chain relaxation and the proton conductivity is investigated. The phosphoric acid alters the relaxation trends, increases the number of free ions in the polymer matrix, and therefore the conductivity. The shift in the peak frequencies of different chain relaxation processes in the presence of PA and PWA/ZrO2 is attributed to the increase in free volume and the consequent easy motion of the polymer chains. The Fourier transform infra-red (FTIR) spectroscopy of ABPBI and the acid-doped composites show all the relevant peaks corresponding to C=C, C=N stretching, and phosphoric acid/phosphates, confirming the formation of ABPBI and doping with PA. The proton conductivity of the membranes is estimated from electrochemical impedance spectroscopy (EIS). To establish the effect of change in crystallinity on relaxations and proton conductivity, the undoped and PA-doped membranes are characterized using thermogravimetric analysis and in situ XRD at high temperatures. (c) 2017 Wiley Periodicals, Inc.
机译：聚（2,5-苯并咪唑）（ABPBI） - 具有使用宽带介电光谱（BDS）的宽范围（-50至220℃）的高温聚合物电解质膜，以了解各种弛豫过程。未掺杂的ABPBI膜显示出两个主要的二次放松和主要弛豫。研究了磷酸（PA）和磷酸钨酸接枝的二氧化锆（PWA / ZrO2）纳米颗粒对链弛豫和质子电导率的影响。磷酸改变了弛豫趋势，增加了聚合物基质中的自由离子的数量，因此增加了导电性。在PA和PWA / ZrO 2存在下不同链弛豫过程的峰值频率的转变归因于自由体积的增加和聚合物链的随之容易运动。 ABPBI的傅里叶变换红外（FTIR）光谱和酸掺杂复合材料显示了对应于C = C，C = N拉伸和磷酸/磷酸盐的所有相关峰，证实了ABPBI的形成并用PA掺杂。从电化学阻抗光谱（EIS）估计膜的质子电导率。为了确定结晶度变化对放松和质子电导率的影响，未掺杂的和PA掺杂的膜的特征在于使用热重分析和在高温下原位XRD。 （c）2017 Wiley期刊，Inc。

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