ISSN:
0098-1273
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The transitions of poly(oxy-2,2′-dimethylazoxybenzene-4,4′-diyloxydodecanedioyl) (PDAD) have been analyzed by differential scanning calorimetry, optical microscopy, and light scattering. The mesophase glass devitrifies at 288 K [ΔCp = 220 J/K mol]. Crystallization from the liquid mesophase can be described between 322 and 362 K by an Avrami expression with an exponent between 3 and 4. Results of light scattering and optical microscopy are in accord with a spherulitic morphology grown after athermal nucleation. Melting of the semicrystalline samples (crystallinity up to 58%) occurs at about 391 K. The heat of fusion of the completely crystalline sample is calculated to be only 13.55 kJ/mol. The mesophase to isotropic phase transition occurs at 418 K with a heat of transition of 4.1 kJ/mol. A general discussion of these transitions is given.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1983.180210110
