ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Two samples of a statistical siloxane copolymer 1 having two different pendant side-chains have been investigated in the liquid-crystalline state using dielectric relaxation spectroscopy. Samples 1a and 1b differed only in the number of precipitations (3 and 12, respectively) used in the purification procedure. Sample 1a, contained side-chain precursor, whereas this contaminant was not detectable in sample 1b. It was found that the dielectric absorption curves for homeotropically-aligned and unaligned specimens of sample 1a, were far broader than those observed for corresponding specimens of sample 1b, and there was evidence of an extra highfrequency shoulder. In addition, the frequency-temperature locations of the overall loss peak differed between the two samples, being consistent with a plasticization effect caused by residual side-chain precursor in sample 1a. It is shown that dielectric relaxation spectroscopy provides a convenient method for monitoring local phase separation and overall plasticization in liquid-crystalline polymers caused by side-chain precursor contamination.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1987.021881127
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