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  • 1
    ISSN: 1572-8935
    Keywords: Block copolyetheresters ; Poly(trimethylene 2,6-naphthalenedicarboxylate) ; Segments ; Thermal transitions ; X-ray diffraction ; Thermal stimulated current
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Block copolyetheresters with hard segments of poly(trimethylene 2,6-naphthalenedicarboxylate) and soft segments of poly(tetramethylene oxide) were prepared by melt polycondensation of dimethyl 2,6-naphthalenedicarboxylate, 1,3-propanediol and poly(tetramethylene ether)glycol (PTMEG) of molecular weights of 650, 1000 and 2000. The block copolyetheresters were characterized by FTIR, 1H NMR, DSC, X-ray diffraction, TSC (thermal stimulated current), DMA and TGA. It was found that the thermal transitions were dependent on the composition. As the charge molar ratio of PTMEG to dimethyl 2,6-naphthalenedicarboxylate, x, increased, the Tm and ΔHm of the polyester segments decreased, which has been also confirmed by the X-ray diffraction data. The polyether segments of the block copolyetheresters derived from PTMEG2000 could crystallize after cooling, but those of the block copolyetheresters derived from PTMEG1000 and PTMEG650 could not crystallize. The DSC, TSC and DMA results show consistent Tg data of the polyether segments. Based on the shift in Tg of the polyether segments, the amorphous parts of the polyether segments and the amorphous parts of the polyester segments were immiscible for the block copolyetheresters derived from PTMEG2000, but became partially miscible for the block copolyetheresters derived from PTMEG1000 and PTMEG650. The TGA results indicated that composition had little effect on thermal degradation under nitrogen.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Polymer bulletin 35 (1995), S. 743-749 
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Block copolyetheresters with hard segments of poly (pentamethylene p,p'-bibenzoate) and soft segments of poly (tetramethylene ether) have been prepared by melt polycondensation of dimethyl p,p'-bibenzoate, 1,5-pentanediol and poly(tetramethylene ether) glycol (PTMEG) with molecular weights of 650, 1000 and 2000. The polymer composition is governed by the charge molar ratio (x) of PTMEG to dimethyl p,p'-bibenzoate. The block copolyetheresters with x=0.05, 0.1 and 0.2 display a monotropic smectic phase due to the poly (pentamethylene p,p'-bibenzoate) segments. But the block copolyetheresters with x=0.3 exhibit no liquid crystalline behavior. The molecular weight of the PTMEG used has significant effect on the glass transition temperature and crystallizability of the polyether segments. It can be seen from the glass transition temperature results that the miscibility between amorphous parts of the polyether segments and those of the polyester segments is also dependent on the molecular weight of the PTMEG used.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 59 (1996), S. 1027-1031 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The low-temperature properties of block copolyetheresters with hard segments of poly(alkylene p,p′-bibenzoate) and soft segments of poly(tetramethylene ether) were investigated by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). In the temperature range of -100 to 60°C, two transition temperatures, a glass transition temperature (Tg) and a melting temperature (Tm), were found by DSC and are attributed to the polyether segments. The Tg monitored by DSC of the polyether segments of the block copolyetheresters is around -68°C and independent of the composition and the type of polyester segment. Thus, the amorphous parts of the polyether segments should be immiscible with the amorphous parts of the polyester segments. The polyether segments of the block copolyetheresters exhibit a lower Tm and a lower crystallinity than those of the poly(tetramethylene ether)glycol due to the presence of the polyester segments. The crystallizability of the polyether segments is dependent on the composition to some extent. The DMA data show that the dynamic modulus drops more abruptly around -10 to 15°C, indicating that the mechanical properties may change significantly due to the melting of the polyether segments. © 1996 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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