A
modulated dsc study on the in situ polymerization of cyclic butylene terephthalate
oligomers |
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Authors: | Z A Mohd Ishak P P Shang J Karger-Kocsis |
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Institution: | (1) School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, Nibong Tebal Penang, Malaysia, 14300;(2) Eastman Chemical Co., Research Laboratories, Kingsport, USA, 1972, 37662-5150, Tennessee;(3) Institut für Verbundwerkstoffe GmbH, Kaiserslautern University of Technology, Kaiserslautern, Germany, 67663 |
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Abstract: | The polymerization of a cyclic butylene terephthalate
(CBT) oligomer was studied as a function of temperature (T=200
and 260°C, respectively) by modulated DSC (MDSC). The first heating was
followed by cooling after various holding times (5, 15 and 30 min) prior to
the second heating which ended always at T=260°C.
This allowed us to study the crystallization and melting behavior of the resulting
polybutylene terephthalate (PBT), as well. In contrary to the usual belief,
the CBT polymerization is exothermic and the related process is superimposed
to that of the CBT melting. The melting behavior of the PBT was affected by
the polymerization mode (performed below or above the melting temperature
of the PBT product) of the CBT. Annealing above the melting temperature of
PBT yielded a product featuring double melting. This was attributed to the
presence of crystallites with different degrees of perfection. The crystals
perfection which occurred via recrystallization/remelting was manifested by
a pronounced exothermic peak in the non-reversing trace. |
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Keywords: | crystallization cyclic butylene terephthalate (CBT) melting modulated DSC polybutylene terephthalate (PBT) ring-opening polymerization |
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