Abstract
Differential scanning calorimetry was used to study relaxations occurring above the glass transition, T g for a number of characterized and fabricated polystyrenes. Part 1 of this study examines the liquid-liquid relaxation temperature, T LL; Part 2 the effects of injection moulding and biaxial orientation of polystyrene; and Part 3 deals with the effects of injection blow moulding.
The rubbery plateau region was found to be bounded by the glass transition, T g, and a weak transition or relaxation, T LL, found above T g as an endothermic slope change in the base line. In some cases, this transition could be enhanced as a step change when molten samples were quenched in liquid nitrogen.
The effect of molecular weight on T g and T LL was similar, and had the relationships T LL/T g=1.07+0.03 forM inw/M n ≃1, and T LL/T g=1.15 ± 0.01 for ¯M w/¯M n > 1.
Similar content being viewed by others
References
R. F. Boyer, J. Polym. Sci. B14 (1966) 267.
S. J. Stadnicki, J. K. Gillham and R. F. Boyer, J. Appl. Polym. Sci. B20 (1976) 1245.
J. B. Enns, R. F. Boyer and J. K. Gillham, Polym. Prepr., Amer. Chem. Soc. B18 (1977) 475.
C. A. Glandt, H. K. Toh, J. K. Gillham and R. F. Boyer, J. Appl. Polym. Sci. B20 (1976) 1277.
J. K. Gillham, J. A. Benci and R. F. Boyer, Polym. Engng Sci B16 (1976) 357.
Idem, ibid. B16 (1976) 357.
R. F. Boyer, J. Appl. Polym. Sci. B33 (1987) 955.
J. K. Gillham and R. F. Boyer in “Thermal Methods in Polymer Analysis” edited by S. W. Shalaby (Franklin Inst. Press, Philadelphia, Pennsylvania, 1978) p. 5.
E. A. Sidorovich, A. I. Marci and N. S. Gashtoe'd, Rubber Chem. Tech. B44 (1971) 166.
J. K. Gillham, AICHE J. B20 (1974) 1066.
C. A. Glandt, H. K. Toh, J. K. Gillham and R. F. Boyer, J. Appl. Polym. Sci B20 (1976) 1277, 2009.
J. K. Gillham, Polym Engng Sci. B19 (1979) 749.
L. E. Nielsen, ibid. B17 (1977) 413.
J. Chen, C. Kow, L. J. Fetters and D. J. Plasek, J. Polym. Sci. Polym. Phys. Edn B20 (1982) 1565.
R. F. Boyer, ibid. B23 (1985) 1.
S. W. Shalaby in “Thermal Characterization of Polymer Materials” edited by E. A. Turi (Academic Press, London, 1981) p. 337.
R. F. Boyer in “Polymer Yearbook 2” edited by R. A. Pethrick (Harwood Academic, 1985) p. 233.
T. G. Fox and P. J. Flury, J. Polym. J. B14 (1954) 315.
L. R. Denny, R. F. Boyer and H. G. Elias, J. Macromolec. Sci Phys. B25 (1986) 277.
S. S. Chang, Polym. Commun. 29 (1988) 33.
E. Janckel and V. Ueberreiter, Z. Physik. Chemie BA182 (1938) 361.
T. G. Fox and P. J. Flury, J. Appl. Phys. B21 (1950) 581.
J. M. G. Cowie, Engng Polym. J. B11 (1975) 297.
R. V. Kokta, J. L. Valade, V. Hornof and K. N. Law, in Proceedings of the fifth meeting of the North N. Americal Thermal Analysis Society, Canada, June 1975.
M. G. Rogers, J. Mater. Sci. 26 (1991) 335–340.
Idem, ibid. 26 (1991) 4285.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Rogers, M.G. Characterization of molecular orientation by differential scanning calorimetry. J Mater Sci 26, 4281–4284 (1991). https://doi.org/10.1007/BF00543637
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF00543637