ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The viscosities of dilute solutions (0.05, 0.1, and 0.2 g. per 100 ml.) of relatively high nitrogen content nitrocelluloses, weight-average molecular weights ca. 100,000, have been studied using homologous series of methyl ketones, alkyl acetates, and dialkyl phthalates as solvents. The simple form of the Huggins equation, \documentclass{article}\pagestyle{empty}\begin{document}$ \eta _{sp} /c = [\eta] + k'[\eta]^2 c $\end{document} does not appear to hold, plots of ηsp/c against c being generally curved. The results are capable of expression by \documentclass{article}\pagestyle{empty}\begin{document}$ \eta _{sp} /c = A + Bc + Cc^2 $\end{document} where A equals [η] and B the initial slope. Values of B and A appear to be related to solvent power as determined by the volume of hexane required to cause initial phase separation from solution, good solvents giving higher values of B and A than poor. The variation of B with solvent is more marked than that of [η] and may reflect differences in degree of coiling of chains in different solvents. Values of B/[η]2 (Huggins k′) do not generally decrease with solvent power increase. The slopes of Martin plots divided by intrinsic viscosities are not generally related to solvent power in the manner observed by Spurlin with solutions of ethyl cellulose.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1951.120070207
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