本研究采用ATMP一步法磷酸化壳聚糖(CS)，然后利用氨基功能化多壁碳纳米管(MWCNTs-NH₂)制备PCS/N-MWCNTs膜。采用傅里叶变换红外(FTIR)、x射线衍射(XRD)、能量色散x射线能谱(EDX)、扫描电镜(SEM)和透射电镜(TEM)对CS和后来的PCS/N-MWCNTs纳米复合膜的磷酸化进行了表征。还对它们的机械性能、吸水率、面积膨胀比、离子交换容量(IEC)和质子电导率进行了评估。MWCNTs的-NH₂基团与-膦酸以及PCS的-NH2基团之间的界面相互作用为质子转移提供了额外的位点，从而提高了PCS/N-MWCNTs膜的质子导电性。这些结果表明，在PCS链中加入N-MWCNTs降低了PCS链的迁移率，最终改善了复合膜的热性能和力学性能。在80℃时，N-MWCNTs含量为5 wt.%的复合膜的质子电导率为0.045 S.cm^?1。因此，PCS/N-MWCNTs纳米复合膜作为PEM可用于燃料电池。利用这一优势，N-MWCNTs填充氢燃料电池优于PCS填充膜。

In this study, a one-step method was enforced for the phosphorylation of chitosan (CS) using ATMP, and later amino functionalized multiwalled carbon nanotubes (MWCNTs-NH₂) were used for the fabrication of PCS/N-MWCNTs membranes. The phosphorylation of CS and later PCS/N-MWCNTs nanocomposite membranes were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). They were also evaluated for their mechanical properties, water uptake, area swelling ratio, ion-exchange capacity (IEC), and proton conductivity. Interfacial interaction among an -NH₂ group of MWCNTs and -phosphonic acid as well as the -NH₂ group of PCS provided extra sites for proton transfer, thus improving the proton conductivity of PCS/N-MWCNTs membranes. These results revealed that the incorporation of N-MWCNTs into PCS chains lowers PCS chain mobility and ultimately improved the thermal and mechanical properties of the composite membranes. The proton conductivity of the composite membrane with 5 wt.% of N-MWCNTs at 80 °C was 0.045 S.cm^?1 . Thus, PCS/N-MWCNTs nanocomposite membranes as a PEM can be used in fuel cells. With this advantage, the N-MWCNTs-fifilled hydrogen fuel cell outperforms compared to PCS fifilled membrane.

图1.磷酸化壳聚糖的反应方案。

  国家自然科学基金(22178317、22109138)资助;中国博士后科学基金(2020M671790)和高等教育委员会;巴基斯坦(编号527/IPFP-II(Batch-I)/ SRGP/NAHE/HEC/2020/275)。