ISSN:
1022-1352
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Five fractions of a polyimide synthesized from 2,2′-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and 2,2′-(trifluoromethyl)-4,4′-biphenyldiamine (PFMB) (6FDA/PFMB) in tetrahydrofuran (THF) at 30°C were investigated by a combination of static and dynamic laser light scattering (LLS). The relations of 〈Rh〉 (nm) = 2.38 x 10-2 Mw0.560 and A2 (mol · cm-3 · g-2) = 2.1 × 10-1 Mw-0.43 were established, where Mw, 〈Rh〉 and A2 are weight-average molecular weight, average hydrodynamic radius and second virial coefficient, respectively. A combination of Mw and the translational diffusion coefficient distribution G(D) leads to a relation of D(cm2/s) = 2.41 × 10-4 M0.564. With this relation, we successfully convert each G(D) into a corresponding molecular weight distribution (MWD). On the basis of the Benoit-Doty theory, we found that the persistence length and the Flory characteristic ratio C∞ of the 6FDA-PFMB chain are ∼3.3 nm and ∼40, respectively, indicating that the 6FDA-PFMB chain is more extended than typical random-coil chains. On the other hand, the ratio of the radius of gyration to the hydrodynamic radius, i.e., 〈Rg〉/〈Rh〉 ∼ 1.8, together with the values of the exponents (∼0.56) indicate that the 6FDA-PFMB chain has a coil chain conformation. Therefore, the 6FDA-PFMB chain has an extended coil conformation in THF at 30°C.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1997.021981123
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