ISSN:
0032-3888
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
The results of dynamic mechanical and broad-line proton magnetic resonance studies carried out over a broad, temperature range on a series of aromatic polyamides are presented. At temperatures lower than 300 K, the NMR data show no relaxation for the all-meta linked benzene rings polyamide, whereas processes for the other polyamides are found, the magnitude of which is dependent on the polymer structure. Between 400 and 500 K further decreases in the second moment take place for all materials. Two secondary mechanical loss peaks are evident in these polymers, one in the 200-380 K region (β) and one in the 380-500 K region (β*), at about 104 cps. In particular, the relaxation strength of the β* peak depends on the conditions of isolation of the polymers from solution. The results are discussed in terms of possible motional processes of these polymers characterized by a long range intramolecular uniaxial order. An attempt is made to correlate the relaxational properties of aromatic polyamides to the existence of a phase of low regularity such as the nematic or smectic mesophases.
Additional Material:
14 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pen.760190110
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