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Authors
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Khonakdar, H. A. ; Golriz, M. ; Jafari, S.H. ; Wagenknecht, U.
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Title
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Correlation of sequence block lengths and degree of randomness with melt rheological properties in PET/PEN blends
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Date
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12.05.2009
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Number
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19189
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Abstract
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PET/PEN blends were prepared over the full composition range via a melt mixing process under various processing conditions. This resulted in transesterification reactions and formation of copolymer structures with various average sequence block lengths and degree of randomness (RD) determined by 1H NMR. It was seen that with an increase in time and temperature of mixing copolymer content (TEN%) and RD increased, whereas the , values were decreased. The differences in the extent of transreactions arising from different processing histories showed their systematic influence on rheological characteristics. Moreover due to progress of transreactions during the rheological measurements, convergence was seen in all the rheological characteristics at terminal zones in the high frequency regions. Similar convergence in the copolymer structural parameters was also obtained by NMR analysis. An increase in TEN% led to a systematic increase in viscosity of the blends. A decrease in the , values results in an increase in elasticity and relaxation time due to improvement of blend interface with increase in extent of copolymer formation.
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Publisher
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Macromolecular Materials and Engineering
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Wikidata
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Citation
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Macromolecular Materials and Engineering 294 (2009) 272-280
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DOI
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https://doi.org/10.1002/mame.200800298
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Tags
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