Thermal Analysis of Acrylonitrile/Acrylic Acid Copolymer Dendrigrafted with Citric Acid

Document Type: Original Article


Department of Textile Engineering, Amirkabir University of Technology


Thermal analysis of acrylonitrile/acrylic acid P(AN/AA) copolymer films containing 5%, 10% and 20% acrylic acid dendrigrafted with citric acid (CA) is examined using differential scanning calorimetry (DSC) with various heating rates, thermogravimetry (TGA) and derivative thermogravimetric analysis (DTG). Also, the effect of carboxylic acid on thermal stabilization of the P(AN/AA) copolymers, when the carboxylic acid groups are in the bulk and when they are on the surface of the films dendrigrafted with CA, were studied using FTIR analyses. It is demonstrated that inclusion of carboxylic acid considerably enhances the rate of thermal degradation. The apparent activation energy (Ea) for overall cyclization and oxidation reactions is calculated using Kissinger’s method. The results reveal that carboxylic acid, when used as a dendrigraft, influences the cyclization and oxidation process in a different way in comparison with when they are in the bulk. The activation energy of the first generation dendrigrafted P(AN/AA) copolymer was lower than that of the copolymer and the forth dendrigraft generation.


Main Subjects

[1] M. S. A. Rahaman, A. F. Ismail and A. Mustafa, “A review of heat
treatment on polyacrylonitrile fiber”, Polym. Degrad. Stab., vol.
92, pp. 1421-1432, 2007.
[2] Z. Bashir, “A critical review of the stabilisation of
polyacrylonitrile”, Carbon., vol. 29, pp. 1081-1090, 1991.
[3] R. Cox, “Acrylic fibers”, in: Synthetic fibers nylon, polyester,
acrylic, polyolefine. ed by McIntyre JE, Woodhead Publishing
Publishing Limitted, Cambridge, England, 2005, pp. 167-234.
[4] K. Sen, S. H. Bahrami and P. Bajaj, “High-performance acrylic
fibere”, J. Macromol. Sci., Rev. Macromol. Chem. Phys., vol. 36,
pp. 1-76, 1996.
[5] Q. Ouyang, L. Cheng, H. Wang and K. Li, “Mechanism and
kinetics of the stabilization reactions of itaconic acid-modified
polyacrylonitrile”, Polym. Degrad. Stab., vol. 93, pp. 1415-1421,
[6] J. S. Tsai and C. Hualin, “Effect of comonomer composition on the
properties of polyacrylonitrile precursor and resulting carbon
fiber”, J. Appl. Polym. Sci. 43: 679-685, 1991.
[7] K. A.Gupta, D. K. Paliwal and P. Bajaj, “Effect of an acidic
comonomer on thermooxidative stabilization of polyacrylonitrile”,
J. Appl. Polym. Sci., vol. 58, pp. 1161-1674, 1995.
[8] I. F. C. Preta, S. K. Sakata, G. Garcia, J. P. Zimmermann, F.
Galembek and C. Giovedi, “Thermal behavior of polyacrylonitrile
polymers synthesized under different conditions and comonomer
composition” J. Therm. Anal. Calorim., vol. 87, pp. 657-659, 2007.
[9] C. Cui, L. Yu and C. Wang, “The degradation and prestabilization
of acrylonitrile copolymers”, J. Appl. Polym. Sci., vol. 117, pp.
1596-1600, 2010.
[10] KA. Gupta, D. K. Paliwal and P. Bajaj, “Melting behavior of
acrylonitrile polymers”, J. Appl. Polym. Sci., vol. 70, pp. 2703-
2709, 1998.
[11] C. Hou, R. Qu, W. Qun and L. Ying, “Determination of
degradation rate of acrylonitrile polymers”, J. Appl. Polym. Sci.,
vol. 101, pp. 1511-1514, 2006.
[12] P. Bajaj, T. V. Sreekumar and K. Sen, “Thermal behaviour of
acrylonitrile copolymers having methacrylic and itaconic acid
comonomers”, Polymer, vol. 42, pp. 1707-1718, 2001.
[13] [13] A. K. Gupta, D. K. Paliwal and P. Bajaj, “Effect of the nature
and mole fraction of acidic comonomer on the stabilization of
polyacrylonitrile”, J. Appl. Polym., Sci. vol. 59, pp. 1819-1826,
[14] S. Soulis and J. Simitzis, “Thermomechanical behaviour of
poly[acrylonitrile-co-(methyl acrylate)] fibres oxidatively treated at
temperatures up to 180 ◦C”, Polym. Int., vol. 54, pp. 1474-1483,
[15] K. Gupta and R. P. Singhal, “Effect of copolymerization and heat
treatment on the structure and x-ray diffraction of
polyacrylonitrile”,J. Polym. Sci., Part B: Polym. Phys., vol. 21, pp.
2243-2262, 1983.
[16] J. Simitzis, and S. Soulis, “Correlation of chemical shrinkage of
polyacrylonitrile fibres with kinetics of cyclization”, Polym, Int.,
vol. 57, pp, 99-105, 2008.
[17] S. Xiao, H. Lv, Y. Tong, , L. Xu and B. Chen, “Thermal behavior
and kinetics during the stabilization of polyacrylonitrile precursor
in inert gas”, J. Appl. Polym. Sci., vol. 122, pp. 480-488, 2011.
[18] M. Yu, C. Wang, Y. Zhao, M. Zhang, W. Wang, “Thermal
properties of acrylonitrile /itaconic acid polymers in oxidative and
nonoxidative atmospheres”, J. Appl. Polym. Sci., vol. 116, pp.
1207-1212, 2010.
[19] E. Fitzer and D. J. Müller, “The influence of oxygen on the
chemical reactions during stabilization of PAN as carbon fiber
precursor”, Carbon., vol. 13, pp. 63-69, 1975.
[20] E. Fitzer, W. Frohs and M. Heine, “Optimization of stabilization
and carbonization treatment of PAN fibres and structural
characterization of the resulting carbon fibres”, Carbon., vol. 24,
pp. 387-395, 1986.
[21] N. Grassie and R. McGuchan, “Pyrolysis of polyacrylonitrile and
related polymers-VI. Acrylonitrile copolymers containing
carboxylic acid and amid structures”, Eur. Polym. J., vol. 8, pp.
257-269, 1972.
[22] S. H. Bahrami, P. Bajaj and K. Sen, “Thermal behavior of
acrylonitrile carboxylic acid copolymers”, J. Appl. Polym. Sci., vol.
88, pp. 685-698, 2003.
[23] R. Devasia, C. P. Reghunadhan, P. Nair, B. K. Sivadasan and K. N.
Ninan, “Cyclization reaction in poly(acrylonitrile/itaconic acid)
copolymer: an isothermal differential scanning calorimetry kinetic
study”, J. Appl. Polym. Sci., vol. 88, pp. 915-920, 2003.
[24] J. J. Liu, H. Ge and C. G. Wang, “Modification of polyacrylonitrile
precursors for carbon fiber via copolymerization of acrylonitrile
with ammonium itaconate”, J. Appl. Polym. Sci., vol. 102, pp.
2175-2179, 2006.
[25] S. J. Teertstra and M. Gauthier, “Dendrigraft polymers:
macromolecular engineering on a mesoscopic scale”, Prog. Polym.
Sci., vol. 29, pp. 277-327, 2004.
[26] J. M. J. Frechet and D. A. Tomalia, “Dendrimers and other
dendritic polymer”, John-Wiley, Chichester, 2001.
[27] F. Vogtle, S. Gestermann, R. Hesse, H. Schwierz and B. Windisch,
“Functional dendrimers”, Prog. Polym. Sci., vol. 25, pp. 987-1041,
[28] C. R. Yates and W. Hayes, “Synthesis and applications of
hyperbranched polymers”, Euro. Polym. J., vol. 40, pp. 1257-1281,
[29] S. Akbari, M. H. Kish and A. A. Entezami, “Copolymer of
acrylonitrile/acrylic acid solid surface film dendrigrafted with citric
acid”, Polym. Int., vol.57, pp. 846-853, 2008.
[30] S. Akbari, M. H. Kish and A. A. Entezami, “Modification of
acrylonitrile/acrylic acid copolymer films and fibers by dendrigraft
Formation”, Polym. Int., vol. 59, pp. 1550-1557, 2010.
[31] S. Akbari, M. H. Kish and A. A. Entezami, “Copolymer of
acrylonitrile/acrylic acid film dendrigrafted with citric acid: Hostguest
properties of dendrigraft -dye complexes and the effects of
acrylic acid content”, Iran. Polym. J., vol. 20, pp. 539-549, 2011.
[32] S. Vyazovkina, A. K. Burnhamb, J. M. Criadoc, L. A. Pérez-
Maquedac, C. Popescud and N. Sbirrazzuolie, “ICTAC Kinetics
Committee recommendations for performing kinetic computations
on thermal analysis data”, Thermochim. Acta., vol. 520, pp. 1-19,
[33] S. Vyazovkin, K. Chrissafis, M. L. Di Lorenzo, N. Koga, M.
Pijolat, B. Roduit, N. Sbirrazzuoli and J. J. Suñol, “ICTAC
Kinetics Committee recommendations for collecting experimental
thermal analysis data for kinetic computations”, Thermochim.
Acta., vol. 590, pp. 1-23, 2014.
[34] B. R. Reyhani, S. Akbari and M. H. Kish, “Dendrigraft with citric
acid on acrylonitrile /acrylic acid copolymer-electrospun fibers”,
Polym. Int., vol. 62, pp. 1767-1776, 2013.
[35] K. Sen, P. Bajaj and T. V. Sreekumar, “Thermal behavior of drawn
acrylic fibers”, J. Polym. Sci., Part B: Polym. Phys., vol. 41, pp.
2949-2958, 2003.
[36] R. L. Blaine and H. E. Kissinger,“Homer Kissinger and the
Kissinger equation”, Thermochim. Acta., vol. 540, pp. 1-6, 2012