| Autor: |
Tuan Ismail, Tuan N. M., Ibrahim, Nor A., Palam, Kosheela D. P., Sendijarevic, Aisa, Sendijarevic, Ibrahim, M. Schiffman, Christi, Hoong, Seng S., Noor, Mohd A. M., Yeong, Shoot K., Idris, Zainab, Malek, Emilia A., Zainuddin, Norhazlin, Sendijarevic, Vahid |
| Předmět: |
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| Zdroj: |
Journal of the American Oil Chemists' Society (JAOCS); Jul2020, Vol. 97 Issue 7, p737-749, 13p |
| Abstrakt: |
Polyester polyols of 2000 g mol−1 M mass were synthesized via polyesterification reaction of butane‐1,4‐diol (1,4‐BDO) with linear dicarboxylic acids (DCAs) of odd and even carbon numbers, ranging from C4 to C10. Melt transition temperatures and crystallization enthalpies of polyester polyols demonstrated differing trends between odd and even chain lengths of their DCA monomeric units, with the latter possessing higher melt transition temperatures and melting enthalpies. The underlying cause of this difference may be attributable to the formation of a crystalline phase between the polyols' alkyl groups, which leads to proper alignment of ester bonds to allow for formation of dipoles that effectively cancel the local polarization. Thermoplastic urethanes (TPUs) were prepared by reacting the polyester polyols with 4,4′‐methylene bis(phenyl isocyanate) (4,4′‐MDI) and 1,4‐BDO chain extender at mole ratio of 1:2:1, respectively. Morphology, thermal and mechanical properties of TPUs were measured. Mechanical properties of TPUs also differ according to even vs. odd chain length of DCA monomeric units: higher hardness, tensile strength, hysteresis and tensile set for the former. The difference in properties is likely related to differences in phase segregation between hard and soft segments as a result of formation of hydrogen bonds as well as dipole–dipole interactions. Therefore, these findings have practical significance in the selection of polyester polyols to design TPUs for their specific applications. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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