ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Viscosities of dilute solutions of six fractions of a 12.2% N cellulose nitrate, covering a molecular weight range of 68,000 to 224,000, in representative solvents have been determined at temperatures between 18 and 60°C. Values of Q in the expression η =AeQ/RT vary with concentration c and molecular weight M in a manner similar to that previously observed with solutions of ethyl cellulose, but the variation of A with c and M appears to be rather more complex in most cases. Intrinsic viscosities can be related to Q, A, the absolute temperature T, and M. With good solvents negative temperature coefficients of [η] are similar in magnitude to those obtained with cellulose trinitrate, but with poorer solvents the temperature coefficients are smaller. Negative temperature coefficients appear to be primarily due to decreases in the value of (ro2/M) where ro2 is the mean square unperturbed end-to-end distance of the chains. The contribution of the swelling factor α appears to be greater with acetone as solvent, and in all cases values of α3 are greater than those obtained with the trinitrate, suggesting that the chains are less stiff. Values of the exponent a in the expression [η] = KMa decrease with increasing temperature suggesting decreasing chain extension, except in the case of nitrobenzene in which association is probable. The values of a also suggest that the chains are less extended than those of the trinitrate.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1960.1204714942
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