Use of a TrI-functional Crosslinking Agent in Styrene/Acrylic Acid Copolymers to Enhance Mechanical Properties for use as Membranes in Fuel Cells

Use of a TrI-functional Crosslinking Agent in Styrene/Acrylic Acid Copolymers to Enhance Mechanical Properties for use as Membranes in Fuel Cells

R. BenavidesL.W. Oenning M.M.S. Paula L. Da Silva C. Kotzian 

Centro de Investigación en Química Aplicada, Blvd. Enrique Reyna H. 140, Saltillo, Coahuila, 25294 México

Laboratorio de Sintesis de Complexos Multifuncionais, Universidade do Extremo Sul Catarinense, Criciuma, SC, Brasil

Hospital Universitario-UAdeC, Av. Madero 1291, Saltillo, Coah.,25000, México

Corresponding Author Email:
15 October 2012
| |
21 January 2013
| | Citation

Alternative copolymers to the well-known Nafion membranes are the styrene/acrylic acid PS/AA) copolymers, which have ad- vantages in cost and availability of raw materials. Previous attempts to improve their mechanical properties involved crosslinking with divinyl benzene, but in this case the use of the tri-functional monomer TMPTMA (trimethylol propane trimethacrylate) is examined. Co- polymers with a PS/AA molar ratio of 94/6 were prepared by a free radical polymerization reaction, including TMPTMA at 0.1, 0.01 and 0.001 % mol concentrations. Reactions were followed by percentage yield (gravimetry), Infrared spectroscopy (FTIR) and extent of crosslinking by gel percentage evaluation (soxhlet extraction) with three different solvents (water, tetrahydrofuran and dichloromethane). Thermal transitions were followed by calorimetry (DSC), stability by thermogravimetry (TGA) and mechanical properties by dynamic me- chanical analysis (DMA). FTIR spectra show typical bands from the copolymer while the corresponding bands associated with crosslink- ing are overlapped; however, gel percentage evaluations show a higher level of crosslinking for the 0.1% TMPTMA copolymer and lack of solubility in water. DSC thermograms indicate an increment in the glass transition (Tg) and TGA exhibits a small increment in thermal stability for the crosslinked copolymers. Elastic moduli suggests a rubbery material for TMPTMA crosslinked copolymers while loss modulus confirms a Tg enhancement as observed by DSC. A 0.1 % TMPTMA copolymer does not form a membrane due to its insolubility and infusibility.


Copolymers, TMPTMA, Fuel cell

1. Introduction
2. Experimental
3. Results and Discussion
4. Conclusion
5. Akcnowledgements

[1] B. Gou, W. Ki Na, B. Diong, Fuel cells: modeling, control, and applications. CRC Press, United States of America, 2010.

[2] J. Zhang, PEM Fuel Cell Electrocatalysts and Catalyst Layers: Fundamentals and Applications, Springer, England, 2008.

[3] S.M.J. Zaidi, T. Matsuura, Polymer Membranes for Fuel Cells, Springer: United States of America, 2009.

[4] B. Liu, W. Hu, G.P. Robertson, Y.S. Kim, Z. Jiang, M. Guiver, Fuel Cells, 10, 45 (2010).

[5] P.C. Deb, A. Mathew, Macromol. Chem. Phys., 199, 2527 (1998).

[6] T.A. Sherazi, M.D. Guiver, D. Kingston, S. Ahmad, M.A. Kashmiri, Xue, Xinzhong, J. Pow. Sourc., 195, 21 (2010).

[7] E. Drioli, L. Giorno, Membrane Operations: Innovative Separa- tions and Transformations, Wiley-VCH, Germany, 2009.

[8] M.M. Paula, L. da Silva, F.E. da Silva, C.V. Franco, R.B. Nu- ernberg, T. Gomes, R. Miranda, Mat. Sci. Engin. C, 29, 599 (2009).

[9] Silverstein R.M., Webster F.X., Kiemle D.J., Spectrometric Identification Organic Compounds, John Wiley & Sons, USA, 2005.

[10] Ali Z.I., Youssef H.A., Said H., Saleh H.H., Adv. Polym. Technol., 25, 3 (2006)

[11] Hatakeyama T., Quinn F.X., Thermal Analysis: Fundamentals and Applications to Polymer Science, John Wiley & Sons, UK, 1999.

[12] J.D. Menczel, R.B. Prime, Thermal analysis of polymers: Fun- damentals and Applications, John Wiley and Sons, USA, 2009. 

[13] Botan R., Nogueira T.R., Lona L.M.F., Wypych F., Polímeros: Ciencia e Tecnologia, 1, 34 (2011).