ISSN:
1436-2449
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Summary A novel approach is proposed to derive the temperature dependent unperturbed dimensions of macromolecules as well as the influence of solvent action on these dimensions: The populations of conformers are analyzed by NMR using low molecular weight analogs in the respective milieu. The microconformers are summed up to yield the macro-conformation, applying Monte-Carlo calculation. Because long distance interactions are nonexisting in the conformational balance of those models, the macrodimensions derived in this way are the unperturbed ones, with and without specific solvent influence, depending on the choosen solvent and temperature. Studies have been carried out using ditactic unpolar head-to-head poly(propylene)s as well as polar head-to-head poly(vinylchloride)s and chlorinated poly(octenamer)s, respectively. Comparison with viscosity and light scattering data prove that for head-to-head poly(vinylchloride)s the dependence of the solvent modified unperturbed dimensions on configuration has identical tendency for calculated and measured data. As an unique consequence of the solvent action it has been derived from the NMR studies on the low molecular weight models for erythrodiisotactic poly(vinylchloride) that the short range interaction of polar solvents decreases the solvent modified unperturbed macrodimensions when compared with those in a virtually non-interacting milieu. Separation of short from long range influences on the expansion factor appears to be realizable by the discussed approach. Solvent modified unperturbed dimensions are discussed in connection with dimensions of macromolecules in the θ-state, in semidilute and in plasticized systems and in compatible polymer blends.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00262126
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