ISSN:
0360-6376
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Two copolymers composed of p-hydroxybenzoate (PHB) and biphenylene terephthalate (BPT) with PHB/BPT ratios of 1/2 and 2/1 were characterized with respect to their tendency to exhibit liquid-crystalline behavior in the melt phase. The BPT -rich copolyester, PHB/BPT = 1/2, displayed a birefringent melt phase of very high viscosity and no tendency to crystallize on cooling. The resulting fused material exhibited what apeared to be a second-order transition at 170°C. The PHB-rich composition, PHB/BPT = 2/1, also exhibited a highly birefringent melt phase of high viscosity which was quite shear sensitive. This polymer melt had little tendency to crystallize on cooling; however, on reheating no apparent second-order transition could be detected. The observed phase changes were characterized by differential scanning calorimetry, hot-stage microscopy, and wide-angle x-ray diffraction techniques. Additional data, pertaining to the compositional nature and apparent sequence distribution, were obtained by 13C-NMR spectroscopy of the solid materials through magic-angle spinning, dipolar decoupling, and cross-polarization techniques.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1983.170210810
