硅氧烷交联的咪唑基团功能化聚苯醚/聚四氟乙烯耐高温质子交换膜

doi:10.7503/cjcu20180721

摘要/Abstract

摘要：

以聚苯醚(PPO)为基体材料, 通过溴甲基化及咪唑基团功能化, 与聚四氟乙烯(PTFE)复合、硅氧烷基团水解交联及磷酸掺杂, 制备了兼具高磷酸掺杂含量、高质子电导率和良好机械性能的高温质子交换膜材料. 以甲基咪唑(MeIm)和咪唑基硅氧烷化合物(SiIm)为功能化试剂(其中咪唑基团提供了磷酸作用位点, 同时SiIm中的硅氧烷基团水解后得到Si—O—Si交联网络结构), 提高了膜材料的机械稳定性. 与PTFE的复合进一步增强了膜材料的机械强度. 结果表明, 复合膜具有较高的电导率和一定的机械强度. 当磷酸掺杂质量分数为242.5%时, PPO-50%SiIm-50%MeIm/PTFE复合膜在160 ℃不加湿条件下的电导率为0.09 S/cm, 室温下的断裂拉伸强度为3.6 MPa.

关键词: 高温质子交换膜, 聚苯醚, 聚四氟乙烯, 咪唑功能化, 硅氧烷交联

Abstract:

Based on poly(2,6-dimethyl-1,4-phenylene oxide)(PPO), novel high temperature proton exchange membranes were prepared with high phosphoric acid content, superior proton conductivity and excellent mechanical properties. Both methylimidazole(MeIm) and triethoxysilylpropyldihydroimidazole(SiIm) were used as functional reagents to graft the imidazolium groups onto the PPO polymer, in which the imidazolium group provided the phosphoric acid interaction sites. Meanwhile crosslinking of the modified PPO was achieved by forming a crosslinked silane network via the hydrolysis reaction of SiIm in an acidmedium. Moreover, porous poly(tetrafluoroethylene)(PTFE) was used as the membrane matrix toenhance the dimensional stabilities and mechanical strength of the fabricated membranes. Physicochemical properties of composite membranes with various crosslinking degrees were investigated accordingly. The results showed that the PPO-SiIm-MeIm/PTFE composite membranes possessed dense structure, superior thermal stability, improved chemical stability, high conductivity and suitable mechanical strength simultaneously. As an example, the PPO-50%SiIm-50%MeIm/PTFE membrane with a phosphoric acid doping content of 242.5% exhibited a conductivity of 0.09 S/cm at 160 ℃ under no humidification conditions, and a tensile strength of 3.6 MPa at room temperature. The results indicate that PPO-x%SiIm-y%MeIm/PTFE membranes have the potential to be used as HT-PEMs.

Key words: High temperature proton exchange membrane, Poly(2, 6-dimethyl-1, 4-phenylene oxide), Porous poly(tetrafluoroethylene), Imidazolium functionalization, Siloxane crosslinking

中图分类号:

O631
O646

TrendMD:

任小蕊, 刘超, 李欢欢, 杨景帅, 何荣桓. 硅氧烷交联的咪唑基团功能化聚苯醚/聚四氟乙烯耐高温质子交换膜. 高等学校化学学报, 2019, 40(5): 1089.

REN Xiaorui,LIU Chao,LI Huanhuan,YANG Jingshuai,HE Ronghuan. Siloxane Crosslinked Imidazolium PPO/PTFE Membranes for High Temperature Proton Exchange Membranes^†. Chem. J. Chinese Universities, 2019, 40(5): 1089.

图/表 8

Scheme 1 Preparation procedure of PA doped PPO-MeIm-SiIm/PTFE composite membranes

Fig.1 FTIR-ATR spectra of BPPO(a), PPO-100%SiIm/PTFE with hydrolysis(b) and PPO-100%SiIm-Un/PTFE without hydrolysis(c) and PPO-50%SiIm-50%MeIm/PTFE membranes(d)

Fig.2 SEM images of the surface of PTFE(A), PPO-50%SiIm-50%MeIm/PTFE(B) and PPO-100%SiIm/PTFE membranes(C), respectively, the cross-section of PTFE(D) and PPO-50%SiIm-50%MeIm/PTFE membranes(E) and EDX element analysis in the selected area for the cross-section of PPO-50%SiIm-50%MeIm/PTFE composite membrane(F)

Fig.3 TGA curves of BPPO(a), PPO-40%SiIm-60%MeIm/PTFE(b), PPO-60%SiIm-40%MeIm/PTFE(c), PPO-100%SiIm/PTFE(d) and PTFE membranes(e) at a heating rate of 10 ℃/min in air

Fig.4 Fenton test results of various PPO-SiIm-MeIm/PTFE membranes in 3%(mass fraction) H2O2 solution containing 4 mg/kg Fe2+ at 68 ℃a. PPO-100%SiIm; b. PPO-100%SiIm/PTFE;c. PPO-60%SiIm-40%MeIm/PTFE; d. PPO-40%SiIm-60%MeIm/PTFE; e. PPO-100%MeIm/PTFE.

Table 1 Acid doping content and swellings of various membranes after immersing in 85%(mass fraction) PA solutions at 60 and 120 ℃

Membrane	Mass fraction of PA(%)		S(%)		V(%)
Membrane	60 ℃	120 ℃	60 ℃	120 ℃	60 ℃	120 ℃
PPO-40%SiIm-60%MeIm/PTFE	267.5	312.7	68.0	80.0	197.5	210.6
PPO-50%SiIm-50%MeIm/PTFE	242.5	—	45.0	—	150.0	—
PPO-60%SiIm-40%MeIm/PTFE	237.5	253.4	39.0	68.0	110.0	145.6
PPO-70%SiIm-30%MeIm/PTFE	232.0	—	39.0	—	102.5	—
PPO-100%SiIm/PTFE	158.0	162.7	26.5	44.0	86.0	94.5

Fig.5 Conductivities of acid doped PPO-SiIm-MeIm/PTFE membranes as a function of temperatures without humidifyinga. PPO-40%SiIm-60%MeIm/PTFE/PA; b. PPO-50%SiIm-50%MeIm/PTFE/PA; c. PPO-60%SiIm-40%MeIm/PTFE/PA; d. PPO-70%SiIm-30%MeIm/PTFE/PA; e. PPO-100%SiIm/PTFE/PA.

Fig.6 Tensile stress-stain curves of acid doped PPO-SiIm-MeIm/PTFE membranes at room temperaturea. PPO-100%SiIm/PTFE; b. PPO-70%SiIm-30%MeIm/PTFE; c. PPO-60%SiIm-40%MeIm/PTFE; d. PPO-50%SiIm-50%MeIm/PTFE; e. PPO-40%SiIm-60%MeIm/PTFE.

参考文献 29

[1]	Zhang H., Shen P. K., Chem. Rev.,2012, 112(5), 2780—2832
[2]	Yang J., Liu C., Gao L., Wang J., Xu Y., Wang T., RSC Adv.,2016, 6, 61029—61036
[3]	Wang P., Wu X., Zhang H. Y., Liu Z. C., Liu B. J., Chem. J. Chinese Universities,2018, 39(3), 405—407
	(王鹏, 吴宪, 张汉宇, 刘振超, 刘佰军. 高等学校化学学报,2018, 39(3), 405—407)
[4]	He R. H., Li Q. F., Bjerrum N. J., Chem. J. Chinese Universities,2005, 26(12), 2302—2305
	(何荣桓, 李庆峰, Bjerrum N. J. 高等学校化学学报,2005, 26(12), 2302—2305)
[5]	Sun P., Li Z., Wang S., Yin X., J. Membr. Sci.,2018, 549, 660—669
[6]	Wang S., Sun P., Li Z., Liu G., Yin X., Int. J. HydrogenEnergy,2018, 43(21), 9994—10003
[7]	Li Q., Jensen J. Q., Savinell R. F., Bjerrum N. J., Prog. Polym. Sci.,2009, 34(5), 449—477
[8]	Li M., Scott K., J. Power Sources,2011, 196(4), 1894—1898
[9]	Wang X., Xu C., Golding B. T., Sadeghi M., Cao Y., Scott K., Int. J. Hydrogen Energy,2011, 36(14), 8550—8556
[10]	Yang J., Li Q., Jensen J. O., Pan C., Cleemann L. N., Bjerrum N. J., J. Power Sources,2012, 205(2), 114—121
[11]	Li Q., Liu L., Liang S., Li Q., Jin B., Bai R., Polym. Chem.,2014, 5(7), 2425—2432
[12]	Papadimitriou K. D., Paloukis F., Neophytides S. G., Kallitsis J. K., Macromolecules,2011, 44(12), 4942—4951
[13]	Guo Z., Xiu R., Lu S., Xu X., Yang S., Xiang Y., J. Mate. Chem. A,2015, 3(16), 8847—8854
[14]	Lu S., Xiu R., Xu X., Liang D., Wang H., Xiang Y., J. Membr. Sci.,2014, 464(16), 1—7
[15]	Wu W., Zou G., Fang X., Cong C., Zhou Q., Ind. Eng. Chem. Res.,2017, 56, 10227—10234
[16]	Yang J., Wang J., Liu C., Gao L., Xu Y., Che Q., J. Membr. Sci.,2015, 493, 80—87
[17]	Lin H. L., Huang J. R., Chen Y. T., Su P. H., Yu T. L., Chan S. H., J. Polym. Res.,2012, 19(5), 9875—9883
[18]	Dong F., Li Z., Wang S., Xu L., Yu X., Int. J. Hydrogen Energy,2011, 36, 3681—3687
[19]	Yang J., Wang Y., Yang G., Zhan S., Int. J. Hydrogen Energy,2018, 43, 8464—8473
[20]	Guo T. Y., Zeng Q. H., Zhao C. H., Liu Q. L., Zhu A. M., Broadwell I., J. Membr. Sci.,2011, 371(12), 268—275
[21]	Yang J., Liu C., Hao Y., He X., He R., Electrochim. Acta,2016, 207, 112—119
[22]	Xu Y. X., Zhang D. J., Ye N. Y., Yang J. S., He R. H., Chem. J. Chinese Universities,2017, 38(10), 1872—1879
	(徐一鑫, 张登骥, 叶妮雅, 杨景帅, 何荣桓. 高等学校化学学报,2017, 38(10), 1872—1879)
[23]	Jheng L. C., Hsu L. C., Lin B. Y., Hsu Y. L., J. Membr. Sci.,2014, 460(12), 160—170
[24]	Chisca S., Duong P. H., Emwas A. H., Sougrat R., Nunes S. P., Polym. Chem.,2015, 6(4), 543—554
[25]	Hu J., Wan D., Zhu W., Huang L., Tan S., Cai X., ACS Appl. Mater. Interfaces,2014, 6(7), 4720—4730
[26]	Xiao L., Zhang H., Jana T., Scanlon E., Chen R., Choe E., Fuel Cells,2005, 5(2), 287—295
[27]	Si Z., Gu F., Guo J., Yan F., J. Polym. Sci., Part B: Polym. Phys.,2013, 51(17), 1311—1317
[28]	Yang J., Li Q., Cleemann L. N., Jensen J. O., Pan C., Bjerrum N. J., Adv. Energy Mater., 2013, 3(5), 622—630
[29]	Xiao L., Zhang H., Scanlon E., Ramanathan L. S., Choe E., Rogers D., Apple T., Benicewicz B. C., Chem. Mater., 2005, 17, 5328—5333