ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
High resolution electron microscopy of sodium lignin sulfonates revealed a granular microstructure of spherical particles of diameters ranging from 30 to 90 A. The weight average particle weight, Pw was computed from the dimensions measured on the electron micrographs and the density of lignin. For a fraction of intermediate molecular weight, the particle diameter derived from Pw was 64 A., in fair agreement with a value of 49 A. computed from the sedimentation equilibrium molecular weight. A high molecular weight fraction contained, in addition to the granular moiety, larger structures which appeared to be aggregates of the granules. The particle weight distribution for the high molecular weight fraction was similar to the distribution of sedimentation constants previously found for alkali lignins. The spherical shapes for both the granules and the aggregates was in accord with the compact spherical configuration previously proposed for lignin sulfonates in aqueous solution.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1964.070080429
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