ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Copolymeric systems of the general formula: P1 = {((—OCH2CH2)a—O—R—)m ((—OCH2CH2)b—O—R—)n}x or P2 = {((—OCH2CH2)a—O—R—)m (—O(CH2)b—O—R—)n}x with R = —OC—C6H4—CH=HC—C6H4—CO— were prepared and their mesophasic properties studied by polarizing microscopy, differential scanning calorimetry and X-ray diffraction analysis. Enantiotropic smectic mesomorphism was directly observed in most cases. For all systems but P2(a = 2, b = 12) a single smectic phase was observed for all compositions, with a continuous variation of the smectic structural periodicity, isotropization temperatures and molar entropic changes close to the weighted average. This indicates a complete compatibility of the different monomer units in the formation of the smectic layers. On the contrary, system P2 (a = 2, b = 12) exhibits two smectic phases each within a definite range of composition. The two phases are sharply distinct as far as the structural periodicity is concerned. Both phases are present in the mesophasic state of copolymer with m = 75.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1986.021870909
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