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Thermal Properties and Crystallinity of Thermotropic Liquid Crystalline Copolyesters Prepared from Poly ethylene terephtalate PET and Rigid Aromatic Units    
Yazarlar
Abdullah Tan
Haydar Altınok
Kırıkkale Üniversitesi, Türkiye
Prof. Dr. Zekeriya YERLİKAYA
Gazi Üniversitesi, Türkiye
Serpil Aksoy
Özet
A series of copolyesters were synthesized by melt-polycondensation reaction of poly(ethylene terephtalate) (PET) with various proportions of equimolar compositions of p-acetoxybenzoic acid (p-ABA), hydroquinone diacetate (HQDA) and terephtalic acid (TPA). Viscosity, liquid crystallinity, thermal properties, degree of crystallinity and thermal stabilitiy of these copolyesters were investigated by Ubbelohde viscometer, hot-stage polarized light microscopy (PLM), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and thermogravimetric analysis (TGA), respectively. On the basis of viscosity measurement, it was observed that intrinsic viscosity values of the copolyesters are increased regularly with increasing amounts of aromatic units (p-ABA, HQDA and TPA) in the polymer chain. Thermotropic liquid crystalline behavior was observed in the copolyesters containing over 50mol% of rigid p-ABA/HQDA/TPA aromatic units. DSC analysis of the anisotropic copolyesters revealed broad and weak endotherms associated with the nematic phases, and the melting temperatures were found to be in the processable region. As the mol% of PET in the polymer chain increased, the specific enthalpies of fusion and the degree of crystallinity of the copolyesters were also increased regularly.
Anahtar Kelimeler
poly(ethylene terephthalate),liquid-crystalline copolyester,thermal properties,crystallinity,copolymerization
Makale Türü Özgün Makale
Makale Alt Türü SSCI, AHCI, SCI, SCI-Exp dergilerinde yayımlanan tam makale
Dergi Adı Journal of Macromolecular Science, Part A
Dergi ISSN 1060-1325
Dergi Tarandığı Indeksler SCI
Makale Dili İngilizce
Basım Tarihi 04-2007
Cilt No 44
Sayı 4
Sayfalar 425 / 431
Doi Numarası 10.1080/10601320601188323
Makale Linki http://www.tandfonline.com/doi/abs/10.1080/10601320601188323