Abstract
Crystalline poly(3-phenyl-4-hydroxybenzoic acid) was prepared by polycondensation of 4-acetoxy-3-phenylbenzoic acid in solution at 320°C. Differential scanning calorimetry (d.s.c.) and wide angle X-ray scattering (WAXS) measurements indicate that this homopolyester forms a nematic melt between 345°C and 465°C. Five copolyesters of 4-hydroxybenzoic acid (HBA) and 4-hydroxy-3-phenylbenzoic acid (3-PhHBA) with varying molar composition were prepared by polycondensation in solution. One additional copolyester was prepared by polycondensation in bulk. 1H n.m.r. spectroscopy revealed a significantly lower reactivity of the phenyl-substituted acetoxybenzoic acid. The influence of the molar composition on crystallinity, phase transitions and stability of the nematic mesophase was studied by d.s.c. and WAXS measurements and by optical microscopy. Heat distortion temperatures were determined by the penetration method. It was found that the copolyesters prepared in bulk and in solution possess quite different properties. Only the copolyester prepared in bulk forms a nematic melt above its melting point at 205 ± 3°C.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
