Copolymers of sodium 4-styrene sulphonate and vinyl derivatives of nitrogen-containing heterocycles

The formation of ion-exchange composite materials based on high molecular weight precursors appears to be an intensively developing area in the synthesis of proton-conducting membranes for fuel cells. In such membranes, proton transfer is often provided by functional polymers simultaneously containing sulphonic acid groups in their composition units along with fragments of vinyl derivatives of nitrogen-containing heterocyclic bases. Proton exchange activity in the latter is determined by the possibility of doping with inorganic acids. In the framework of this study, for the further formation of hybrid composite membranes under conditions of radical initiation, copolymers of sodium 4-styrene sulphonate (SSt) with 4-vinylpyridine (VP) and 1-vinylimidazole (VIM) were obtained. The monomodal nature of the turbidimetric titration curves for solutions of copolymerisation reaction products indicates the presence of true copolymers during the process of formation. The composition and structure of the copolymers were characterised using data from elemental analysis, as well as from IR and ¹³C NMR spectroscopy. Constants of the relative activity for the monomers and the microstructure parameters of the polymer chains are calculated according to the non-linear leastsquares method using the MathCAD package. The calculated copolymerisation constant values indicate a greater reactivity of SSt in comparison with nitrogen-containing monomers. The lengths of the monomer unit blocks depend on the composition of the initial mixture and vary over a wide range from 1 to 18. The possibility of varying the length of the unit blocks in the composition of the copolymers will affect the ion-conducting properties of hybrid composites formed on their basis. The stability of the copolymers to thermal oxidative degradation by heating in air was studied using the differential scanning calorimetry (DSC) method. The copolymers demonstrated significant thermo-oxidative stability. Decomposition temperatures were 350 °С and 400 °С for SSt-VIM and SSt-VP copolymers, respectively. 

1. Dobrovolskii Yu.A., Volkov E.V., Pisareva A.V., Fedotov Yu.A., Likhachev D.Yu., Rusanov A.L. Proton-exchange membranes for hydrogen-air fuel cells. Russian Journal of General Chemistry. 2007, vol. 77, issue 4, pp. 766–777.

2. Stenina I.A., Yaroslavtsev A.B. High-temperature and composite proton-conducting electrolytes. Inorganic Materials. 2017, vol. 53, issue 4, pp. 343–353. DOI: 10.1134/S0020168517040161

3. Stelmakh S.A., Mognonov D.M., Grigor’eva M.N., Ukshe A.E., Novikova K.S., Kayumov R.R., Dobrovolsky Y.A., Bal’zhinov S.A. Proton conductivity of new type medium-temperature proton exchange membranes. Ionics. 2016, vol. 22, no.10, pp. 1873–1880.

4. Wong C.Y., Wong W.Y., Ramya K., Khalid M., Loh K.S., Daud W.R.W., Lim K.L., Walvekar R., Kadhum A.A.H. Additives in proton exchange membranes for lowand high-temperature fuel cell applications: A review. International Journal Hydrogen Energy. 2019, vol. 44, no. 12, pp. 6116–6135. DOI:10.1016/j.ijhydene.2019.01.084

5. Kundu P.P., Pal A. Cation exchange polymeric membranes for fuel cells. Reviews in Chemical Engineering. 2006, vol. 22, issue 3, pp. 125–153. DOI: 10.1515/REVCE.2006.22.3.125

6. Qin C., Wang J., Yang D., Li B., Zhang C. Proton exchange membrane fuel cell reversal: A review. Catalysts. 2016, vol. 6, no. 12, pp. 197–218. DOI:10.3390/catal6120197

7. Rozière J., Jones D.J. Non-fluorinated polymer materials for proton exchange membrane fuel cells. Annual Review of Materials Research. 2003, vol. 33, pp. 503–555. DOI:10.1146/annurev.matsci.33.022702.154657

8. Hsu C.Y., Kuo M.H., Kuo P.L.. Preparation, characterization, and properties of poly(styreneb-sulfonated isoprene)s membranes for proton exchange membrane fuel cells (PEMFCs). Journal of Membrane Science. 2015, vol. 484, no. 8, pp. 146–153. DOI: 10.1016/j.memsci.2015.02.038

9. Safronova E.Y., Yaroslavtsev A.B., Parshina A.V., Yankina K.Y., Ryzhkova E.A., Lysova A.A., Bobreshova O.V. Hybrid materials based on MF-4SK membranes and hydrated silica and zirconia with sulfonic acid-functionalized surface: transport properties and characteristics of DP-sensors in amino acid solutions with varying pH. Petroleum Chemistry. 2017, vol. 57, issue 4, pp. 327– 333. DOI: 10.1134/S0965544117040077

10. Helen M., Viswanathan B., Srinivasa Murthy S. Synthesis and characterization of composite membranes based on -zirconium phosphate and silicotungstic acid. Journal of Membrane Science. 2007, vol. 292, no. 1-2, pp. 98–105.

11. Kuznetsova E.V., Safronova E.Yu., Ivanov V.K., Yurkov G.Yu., Yaroslavtsev A.B. The synthesis and study of the transport properties of hybrid materials based on MF-4SK perfluorosulfonated cation-exchange membranes modified with ceria. Petroleum Chemistry. 2011, vol. 51, issue 8, pp. 652–656.

12. Prikhno I.A., Safronova E.Y., Ilyin A.B. Hybrid membranes synthesized from a Nafion powder and carbon nanotubes by hot pressing. Petroleum Chemistry. 2017, vol. 57, no. 13, pp. 1228–1232. DOI: 10.1134/S0965544117130084

13. Tasaki K., DeSousa R., Wang H.B., Gasa J., Venkatesan A., Pugazhendhi P., Louyfly R.O. Fullerene composite proton conducting membranes for polymer electrolyte fuel cells operating under low humidity conditions. Journal of Membrane Science. 2006, vol. 281, no. 31, pp. 570–580.

14. Ramani V., Kunz H.R., Fenton J.M. Investigation of Nafion/HPA composite membranes for high temperature/low relative humidity PEMFC operation. Journal of Membrane Science. 2004, vol. 232, issue 1-2, pp. 31–44. https://doi.org/10. 1016/j.mem sci. 2003.11.016

15. Kayumov R.R., Shmygleva L.V., Dobrovolsky Y.A. Conductivity of Nafion®115 membranes doped with inorganic acids. Russian Journal of Electrochemistry. 2015, vol. 51, no. 6, pp. 556–560.

16. Yaroslavtsev A.B., Dobrovolsky Y.A., Shaglaeva N.S. Frolova L.A., Gerasimova E.V., Sanginov E.A. Nanostructured materials for low-temperature fuel cells // Russian Chemical Reviews. 2012, vol. 81, issue 3, pp. 191–220.

17. Farrukh A., Ashraf F., Kaltbeitzel A., Ling X., Wagner M., Duran H., Ghaffar A., Ur Rehman H., Parekh S.H., Domke K.F., Yameen B. Polymer brush functionalized SiO2 nanoparticle based Nafion nanocomposites: A novel avenue to low-humidity proton conducting membranes. Polymer Chemistry. 2015, vol. 6, issue 31, pp. 5782–5789. DOI:10.1039/C5PY00514K

18. Mosa J., Durán A., Aparicio M. Sulfonic acidfunctionalized hybrid organic–inorganic proton exchange membranes synthesized by sol–gel using 3-mercaptopropyl trimethoxysilane (MPTMS). Journal of Power Sources. 2015, vol. 297, pp. 208–216. DOI: 10.1016/j.jpowsour.2015.06.119

19. Lee J., Yi C.-W., Kim K. Phosphoric aciddoped SDF-F/poly(VI-co-MPS)/PTFE membrane for a high temperature proton exchange membrane fuel cell // Bulletin of the Korean Chemical Society. 2011, vol. 32, issue 6, pp. 1902–1906. https://doi.org/10. 5012/bkcs.2011.32.6.1902

20. Lebedeva O.V., Malahova E.A., Sipkina E.I., Chesnokova A.N., Kuzmin A.V., Maksimenko S.D., Pozhidaev Y.N., Rzhechitskiy A.E., Raskulova T.V., Ivanov N.A. Ion exchange membranes based on silica and sulfonated copolymers of styrene with allyl glycidyl ether. Petroleum chemistry. 2017, vol. 57, no. 9, pp. 763–769.