Abstract
Specific heat capacities of a homogeneous ethylene-1-octene copolymer were measured by adiabatic calorimetry in the temperature range from 5 to 400 K (stepwise heating at averaged rates of approximately 1 to 34 K h–1, after cooling at rates in the range from 8 K h–1 to 4 K min–1). The glass transition takes place from roughly 205 to225 K and is centred around approximately 215 K. At the latter temperature, also the temperature drifts during the stabilisation periods are at maximum. Clearly, with devitrification above 215 K also melting sets in. Using two sets of reference data (one for branched and linear polyethylenes, BPE, and the other for strictly linear polyethylene, LPE)for completely crystalline and for completely amorphous material, the crystallinity of the polymer was calculated as a function of temperature, within the two-phase model. In heating, the crystallinity decreased from 0.254 to zero in the temperature range from 220 to 360 K, confirming earlier DSC heat capacity measurements. During the stabilisation periods, below325 K, negative drifts were observed, related to endothermic effects caused by melting. However, in the temperature range from 325 K up to the end melting temperature, 360 K, positive drifts were measured, reflecting exothermic effects. These are attributed to recrystallisation phenomena. The occurrence and amount of recrystallisation depend on the thermal history of the sample: slower cooling and a longer time spent at a temperature of annealing clearly diminish recrystallisation.
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V. B. F. Mathot (Ed.), Calorimetry and Thermal Analysis of Polymers, Hanser Publishers, Munich, Vienna, New York 1994.
J. C. van Miltenburg, V. B. F. Mathot, P. J. van Ekeren and L. D. Ionescu, J. Therm. Anal. Cal., 56 (1999) 1017.
S. Hosoda, A. Uemura, Y. Shigematsu, I. Yamaamoto and K. Kojima, Stud. Surf. Sci. Catal., 89 (1994) 365.
Y.-C. Hwang, S. Chum, R. Guerra and K. Sehanobish, Antec '94 SPE Conf. Proc., Vol. III (1994) 3414.
J. C. van Miltenburg, A. C. G. van Genderen and G. J. K. van den Berg, Thermochim. Acta, 319 (1998) 151.
J. C. van Miltenburg, G. J. K. van den Berg and M. J. van Bommel, J. Chem. Thermodyn., 19 (1987) 1129.
H. Preston-Thomas, Metrologia, 27 (1990) 3 and Metrologia, 27 (1990) 107.
B. Wunderlich and G. Czornyj, Macromolecules, 10 (1977) 906.
V. B. F. Mathot, Polymer, 25 (1984) 579.
ATHAS data bank. For a recent description see: B. Wunderlich, Pure and Appl. Chem., 67 (1995) 1019. Detailed information may also be found on the internet: http://web.utk.edu/~athas
V. B. F. Mathot, R. L. Scherrenberg, M. F. J. Pijpers and W. Bras, J. Thermal Anal., 46 (1996) 681.
V. B. F. Mathot, R. L. Scherrenberg, M. F. J. Pijpers and Y.M.T. Engelen, Structure, Crystallisation and Morphology of Homogeneous Ethylene-Propylene, Ethylene-1-Butene and Ethylene-1-Octene Copolymers with High Comonomer Contents, in: S. Hosoda (Ed.), The New Trends In Polyolefin Science and Applications, Research Signpost, Trivandrum (India) (1996) 71.
V. B. F. Mathot, Chapter 5: Thermal Characterization of States of Matter, in: V. B. F. Mathot (Ed.), Calorimetry and Thermal Analysis of Polymers, Hanser Publishers, Munich, Vienna, New York 1994, p. 105.
P. J. van Ekeren, Chapter 2: Thermodynamic Background to Thermal Analysis and Calorimetry, in: M. E. Brown (Ed.), Handbook of Thermal Analysis and Calorimetry. Volume I: Principles and Practice, Elsevier, Amsterdam 1998, p. 75.
V. B. F. Mathot, R. L. Scherrenberg and M. F. J. Pijpers, Polymer, 39 (1998) 4541.
R. Scherrenberg, V. Mathot and A. van Hemelrijck, Thermochim. Acta, 330 (1999) 3.
R. Androsch, Polymer, 40 (1999) 2805.
A. Wurm, M. Merzlyakov and C. Schick, Thermochim. Acta, 330 (1999) 121.
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van Ekeren, P.J., Ionescu, L.D., Mathot, V.B.F. et al. Heat Capacities and Thermal Properties of a Homogeneous Ethylene-1-octene Copolymer by Adiabatic Calorimetry. Journal of Thermal Analysis and Calorimetry 59, 683–697 (2000). https://doi.org/10.1023/A:1010185200313
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DOI: https://doi.org/10.1023/A:1010185200313