Synthesis and thermal transition behavior of model thermoplastic polyurethanes containing MDI/butanediol‐based monodisperse hard segments |
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Authors: | Li Ren Nam‐Goo Kang Priyank N Shah Rudolf Faust |
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Institution: | Polymer Science Program, Department of Chemistry, University of Massachusetts Lowell, Lowell, Massachusetts |
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Abstract: | Amine‐terminated monodisperse hard segments (MDHSs) containing two to four 4,4′‐methylenebis (phenyl isocyanate) extended by 1,4‐butanediol have been synthesized using carboxybenzyl protecting‐deprotecting strategy. Pure MDHSs in large scale were obtained in good yield and their structures were confirmed by 1H‐, 13C‐NMR spectroscopy and GPC‐MALLS. Differential scanning calorimetry (DSC) showed that as the hard segment (HS) size increased, the melting and glass transition temperature and the change of heat capacity at glass transition of ethyl capped MDHSs increased. Model thermoplastic polyurethanes (TPUs) were synthesized using the reaction of bischloroformate of poly (tetramethylene oxide) (PTMO) diol or polyisobutylene (PIB) diol with amine‐terminated MDHSs. X‐ray diffraction results indicated the amorphous structure of model TPUs. DSC revealed HS related endotherms, regardless of SS, which were attributed to the local ordering of the HSs. Additional endotherms in PTMO based model TPUs might arise from the dissociation of hydrogen bonding between PTMO and HSs. The lower Tg in model TPUs compared to the polydisperse analogues observed by dynamic mechanical analysis (DMA) indicated higher microphase separation of monodisperse HSs. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3171–3181 |
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Keywords: | carboxybenzyl microphase separation monodisperse hard segments polyisobutylene protecting‐deprotecting thermoplastic polyurethanes |
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