Preparation and characterization of poly(butylene terephthalate)/poly(ethylene terephthalate) copolymers via solid‐state and melt polymerization |
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| Authors: | M A G Jansen L H Wu J G P Goossens G DE Wit C Bailly C E Koning |
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| Institution: | 1. Laboratory of Polymer Technology, Faculty of Chemical Engineering and Chemistry, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands;2. Dutch Polymer Institute, PO Box 902, 5600 AX Eindhoven, The Netherlands;3. Department of Chemical Engineering and Chemistry, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China;4. Dutch Polymer Institute, PO Box 902, 5600 AX Eindhoven, The NetherlandsLaboratory of Polymer Technology, Faculty of Chemical Engineering and Chemistry, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands;5. Laboratory of Polymer Chemistry, Faculty of Chemical Engineering and Chemistry, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands;6. Laboratoire de Chimie et de Physique des Hauts Polymères, Université Catholique de Louvain, Place Croix du Sud, 1 B‐1348 Louvain‐la‐Neuve, Belgium |
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| Abstract: | To increase the Tg in combination with a retained crystallization rate, bis(2‐hydroxyethyl)terephthalate (BHET) was incorporated into poly(butylene terephthalate) (PBT) via solid‐state copolymerization (SSP). The incorporated BHET fraction depends on the miscibility of BHET in the amorphous phase of PBT prior to SSP. DSC measurements showed that BHET is only partially miscible. During SSP, the miscible BHET fraction reacts via transesterification reactions with the mobile amorphous PBT segments. The immiscible BHET fraction reacts by self‐condensation, resulting in the formation of poly(ethylene terephthalate) (PET) homopolymer. 1H‐NMR sequence distribution analysis showed that self‐condensation of BHET proceeded faster than the transesterification with PBT. SAXS measurements showed an increase in the long period with increasing fraction BHET present in the mixtures used for SSP followed by a decrease due to the formation of small PET crystals. DSC confirmed the presence of separate PET crystals. Furthermore, the incorporation of BHET via SSP resulted in PBT‐PET copolymers with an increased Tg compared to PBT. However, these copolymers showed a poorer crystallization behavior. The modified copolymer chain segments are apparently fully miscible with the unmodified PBT chains in the molten state. Consequently, the crystal growth process is retarded resulting in a decreased crystallization rate and crystallinity. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 882–899, 2007. |
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| Keywords: | modification morphology polycondensation polyesters |
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