ISSN:
0887-6266
Keywords:
blends, miscible, local order in
;
light scattering, depolarized, by miscible blends of dissimilar polymers
;
ordering and specific interaction in miscible blends of dissimilar polymers
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Depolarized light scattering measurements on single-phase mixtures of dissimilar polymers, poly(methyl methacrylate) (PMMA)/poly (acrylonitrile-co-styrene) (SAN, AN content = 15 wt %) and PMMA/poly (vinylidene fluoride) (PVDF) were carried out. The effective mean-square optical anisotropy γ2 of the mixtures was found to be much higher than that estimated by the simple additivity of γ2 of component polymers. From the deviation, the order parameter (1 + J12) was estimated to be in a range of 2-13, depending on the blend composition. This suggests local ordering in the single-phase mixtures, i.e., nematic alignment of the locally stretched dissimilar chains. In contrast, the deviation was slight in the polymer/solvent systems, SAN/MMA (monomer) and PVDF/butanone. The degree of ordering decreased with increasing temperature. T. The Specific interaction evidenced by FTIR spectroscopy exhibited a similar temperature dependence. Thus, local ordering seems to be induced by specific interactions and chain connectivity. The temperature dependence of J12 was successfully described by the Landau-de Gennes theory; J-112 ∞ (T + T0)/ T, T0 being the isotropic-nematic transition temperature, as in the case of liquid crystals.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/polb.1991.090291211
