Synthesis, Characterization and Thermal Stability Study of Styrene-based Ionomers I) Programmed Heating Experiments (10 oC/min to 500 oC)

Document Type: Research Article

Author

School of Public Health, Tehran University of Medical Sciences, P.O.Box 14155-6145, Tehran, I.R. IRAN

Abstract

Ionomers are generally described by copolymers having either acrylic or methacylic acid as one component and the other component is mostly either ethylene or styrene. The objective of this research was to study the thermal behaviour and stability of ionomers of styrene with some alkali metal acrylates. These materials have been synthesized by neutralization of the respective copolymer containing 40 mole percent acrylic acid with sodium and potassium hydroxides in acetone medium.The copolymer of styrene–acrylic acid was made by solution polymerization in methanol using 2,2’-azobisbutyronitrile (AIBN) as initiator under nitrogen blanket at 60 oC. Copolymer composition was calculated from the monomer feed concentration. The ionomer samples were characterized using FTIR technique. Thermal behaviour of the ionomers has been studied under programmed heating in dynamic nitrogen atmosphere by using differential thermal analysis (DTA) and thermogravimetry (TG) and in vacuo using thermal volatilization analysis (TVA) techniques supported by product analysis. The thermal behaviour of the sodium and potassium salts of styrene-acrylic acid copolymer is found to be rather similar. Infrared spectroscopy, mass spectrometry and GC-MS techniques were used to examine the degradation products from TVA degradation. Quantitative measurements of the main product fractions under normal TVA conditions have been made. It is found that the main decomposition of the styrene-acrylic acid salts copolymers starts at about 350 oC and reaches maximum at 450 oC.

Keywords

Main Subjects


[1]  Hirasawa, E., Yamamoto, Y., Tadano, K. and Yano, S., Effect of metal cation type on the structure and properties of ethylene ionomers, J. Appl. Polym. Sci., 42, 351 (1991).
[2] Suchocka-Galas, K., Some Properties of Styrene-based Ionomers, J. Appl. Polym.  Sci., 89, 55 (2003).
[3] McNeill, I.C. and Alston, A., Thermal Degradation Behaviour of Acrylic Salt Polymers and Ionomers, Die Angew. Makromol. Chemie, 261/262, 157 (1998).
[4] Suchocka-Galas, K., Koscieleczka, A., Wojtczak, Z. and Wojdylo,  K., Polimery, 27, 383 (1982).      
[5] Suchocka-Galas, K., J. Thermal Anal., 32, 315 (1987).
[6] McNeill, I.C., Polymer Degradation and Characte-rization by Thermal Volatilization Analysis with Differential Condensation of Products, Europ. Polym. J., 6, 373 (1970).
[7] McNeill, I.C. and Stevenson, W.T.K., Polym. Deg. Stab., 10, 247 (1985).
[8] Guaita, M., Chiantore, O. and Costa, L., Polym. Deg. Stab., 12, 315 (1985).
[9] Costa, L., Camino, G., Guyot, A., Bert, M., Clovet, G. and Brossas, J., Polym. Deg. Stab., 15, 219 (1986). 
[10] Sadeghi, S.M.T., Thermal Stability and Degradation Mechanism of Styrene-acrylic Acid Copolymer,Iranian Journal of Polymer Science & Technology, 4, 111 (1991).  
[11] McNeill, I.C. and Sadeghi, S.M.T., Thermal Stability and Degradation Mechanisms of Poly (acrylic acid) and its Salts(Na and K), Polym. Deg. Stab., 30, 213 (1990).
[12] Zulfiqar, S., Masud, K., Siddique, B. and Piracha, A., Thermal Degradation of Phenyl Methacrylate-Styrene Copolymers, Polym. Deg. Stab., 52, 293 (1996).
[13] Zulfiqar,  S., Masud, K. and Ameer, Q., Thermal Degradation of Blends of Phenyl Methacrylate-Styrene Copolymers with Aluminium Ethoxide, Polym. Deg. Stab., 77, 457 (2002).
[14] Maria Switala - Zeliaskow, Thermal Degradation of Copolymers of Styrene with Dicarboxylic Acid,Polym. Deg. Stab., 74, 579 (2001).
[15] Norman S. Allen, Michele Edgc, Miguel Rodriguez, Cristopher M. Liaun, Eusebio Fontan, Aspects of the Thermal Oxidation, Yellowing and Stabilisation of Ethylene Vinyl Acetate Copolymer, Polym. Deg. Stab., 71, 1 (2001).
[16] McNeill, I.C., Ahmed, S. and Memetea, L., Thermal Degradation Studies of Alternating Copolymers, Polym. Deg. Stab., 46, 303 (1994).
[17] Billmeyer, F.W., Textbook of Polymer Science, John Wiley & Sons, Inc., New  York, (1984).
[18] Urban, M.W., Koeing, J.L., Shih, L.B. and Allaway, J.R., Applied Spectroscopy, 41, 590 (1987).
[19] McNeill, I.C., Ackerman, L., Gupta, S.N., Zulfiqar, M. and Zulfiqar, S., j. Polym. Sci., Polym. Chem. Ed., 15, 2381 (1977). 
[20] McNeill, I.C. and Sadeghi, S.M.T., Thermal Stability and Degradation Mechanisms of Poly(acrylic acid) and its Salts : Part 1 - Poly(acrylic acid), Polym. Deg. Stab., 29, 233 (1990).
[21] McNeill, I.C. and Rincon, A., Degradation Studies of Some Polyesters and Polycarbonates : Part 5 - Poly(trimethylene carbonate), Polym. Deg. Stab., 24, 59 (1989).