Abstract
General purpose poly(styrene) is a large volume commodity polymer used in a variety of applications. It is widely used in food packaging, particularly for baked goods. In this application, the presence of styrene monomer, which has a distinctive taste and aroma, cannot be tolerated. Processing of the polymer and forming of the food container at an unacceptably high temperature leads to the formation of styrene monomer and finished articles with unacceptable aroma characteristics.
An examination of the thermal degradation of poly(styrene) has revealed the origin of monomer formation. The thermal decomposition of poly(styrene) has been widely studied. However, most studies have been carried out at high temperature (>300°C) where many processes are occurring simultaneously. Degradation at lower temperature, 280°C, occurs in two well-defined steps. The first is thermolysis of a head-to-head bond present in the mainchain as a consequence of polymerization termination by radical coupling. This generates macroradicals which smoothly depolymerize to expel styrene monomer. The nature of the degradation is readily apparent from kinetic analysis of the isothermal thermogravimetry (TG) data and the identity of the single volatile product may be readily established by gas chromatography/mass spectrometry (GC/MS) analysis of the effluent from the TG analysis.
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References
H. Staudinger and A. Steinhofer, Ann., 571 (1935) 35.
N. Grassie and G. Scott, ’Polymer Degradation and Stabilization’, Cambridge University Press, Cambridge, UK 1985.
H. H. F. Jellinek, J. Polym. Sci., 3 (1948) 850.
H. H. F. Jellinek, J. Polym. Sci., 4 (1948) 13.
G. G. Cameron, W. A. J. Bryce and I. T. McWalter, Eur. Polym. J., 6 (1984) 563.
B. A. Howell, Y. Cui, K. Chaiwong and H. Zhao, J. Vinyl Add. Tech., 12 (2006) 198.
N. Grassie and W. W. Kerr, Trans. Faraday Soc., 53 (1957) 249.
N. Grassie and W. W. Kerr, Trans. Faraday Soc., 55 (1959) 1050.
S. L. Madorsky, J. Polym. Sci., 9 (1952) 133.
S. L. Madorsky, D. McIntyre, J. H. O’Mara and S. Straus, J. Res. Natl. Bur. Std., 66A (1962) 307.
S. L. Madorsky and S. Straus, J. Res. Natl. Bur. Std., 40 (1948) 417.
O. Chiantore and M. Guaita, Polym. Degrad. Stab., 12 (1985) 141.
M. Guaita, Britsh Polym. J., 18 (1985) 226.
H. Inoue, M. Helbig and O. Vogl, Macromolecules, 10 (1977) 1331.
I. Luederwald and O. Vogl, Macromol. Chem., 180 (1979) 2295.
B. A. Howell, Y. Cui and D. B. Priddy, Thermochim. Acta, 396 (2003) 167.
B. A. Howell and K. Chaiwong, ’Thermal Stability of Poly(styrene) Containing no Head-to-Head Units’, Proceedings, 33rd Annual Meeting of the North American Thermal Analysis Society, 2005.
D. R. Hensley, S. D. Goodrich, A. Y. Huckstep, H. J. Harwood and P. L. Rinaldi, Macromolecules, 28 (1995) 1586 and references cited therein.
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Howell, B.A. The utilization of TG/GC/MS in the establishment of the mechanism of poly(styrene) degradation. J Therm Anal Calorim 89, 393–398 (2007). https://doi.org/10.1007/s10973-006-8152-7
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DOI: https://doi.org/10.1007/s10973-006-8152-7