Melting and Crystallization of Poly(butylene terephthalate) by Temperature-Modulated and Superfast Calorimetry M. PYDA, 1,2,3 E. NOWAK-PYDA, 1 J. HEEG, 4 H. HUTH, 4 A. A. MINAKOV, 4 * M. L. DI LORENZO, 5 C. SCHICK, 4 B. WUNDERLICH 1,2 1 Department of Chemistry, The University of Tennessee, Knoxville, Tennessee 37996-1600 2 Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 3 Department of Chemistry, The University of Technology, Rzeszow, 35959 Rzeszow, Poland 4 Universita ¨t Rostock, Inst. f. Physik, Universita ¨tsplatz 3, 18051 Rostock, Germany 5 Istituto di Chimica e Tecnologia dei Polimeri-CNR, Via Campi Flegrei, 34, 80078 Pozzuoli (NA), Italy Received 20 October 2005; revised 9 January 2006; accepted 13 February 2006 DOI: 10.1002/polb.20789 Published online in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: Quantitative temperature-modulated differential scanning calorimetry (TMDSC) and superfast thin-film chip calorimetry (SFCC) are applied to poly(butylene terephthalate)s (PBT) of different thermal histories. The data are compared with those of earlier measured heat capacities of semicrystalline PBT by adiabatic calorimetry and standard DSC. The solid and liquid heat capacities, which were linked to the vibra- tional and conformational molecular motion, serve as references for the quantitative analyses. Using TMDSC, the thermodynamic and kinetic responses are separated between glass and melting temperature. The changes in crystallinity are evaluated, along with the mobile–amorphous and rigid–amorphous fractions with glass transitions cen- tered at 314 and 375 K. The SFCC showed a surprising bimodal change in crystallization rates with temperature, which stretches down to 300 K. The earlier reported thermal activity at about 248 K was followed by SFCC and TMDSC and could be shown to be an irreversible endotherm and is not caused by a glass transition and rigid–amorphous fraction, as assumed earlier. V V C 2006 Wiley Periodicals, Inc.* J Polym Sci Part B: Polym Phys 44: 1364–1377, 2006 Keywords: calorimetry; crystallinity; heat capacity; poly(butylene terephthalate); reversing heat capacity; rigid-amorphous fraction; superfast calorimetry; TMDSC INTRODUCTION The first detailed thermal analysis of semicrystal- line poly(butylene terephthalate) (PBT) based on standard differential scanning calorimetry (DSC) 1 was recently updated with results from adiabatic calorimetry. 2 In the present article, additional temperature-modulated differential scanning calo- rimetry (TMDSC) is presented for a series of PBTs of different thermal histories, supplementing some earlier work on TMDSC of PBT. 3–6 General infor- The submitted manuscript has been authored by a contrac- tor of the U.S. Government under the contract No. DE-AC05- 96OR22464. Accordingly, the U.S. Government retains a nonex- clusive, royalty-free license to publish, or reproduce the pub- lished form of this contribution, or allow others to do so, for U.S. Government purposes. *On leave from the Natural Science Research Centre of A.M. Prokhorov General Physics, Institute of the Russian Academy of Science, Vavilov st. 38, 119991 Moscow, Russia. Correspondence to: B. Wunderlich (E-mail: Wunderlich@ CharterTN.net) Journal of Polymer Science: Part B: Polymer Physics, Vol. 44, 1364–1377 (2006) V V C 2006 Wiley Periodicals, Inc. *This article is a U.S. Government work and, as such, is in the public domain in the United States of America. 1364