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:
The fine structure of cotton cellulosic fibers carbamoylethylated and carboxyethylated at 30 and 20°C in the presence of 3% and 20% sodium hydroxide was investigated by measuring moisture regain, water imbibition, x-ray photograph, degree of crystallinity, spacing, and crystallite size under dry and wet conditions. As carbamoylethyl and carboxyethyl substituents are introduced in amorphous regions of the samples reacted with acrylamide in 3% sodium hydroxide, the fine structure of the crystalline regions is not affected by the reaction. On the other hand, in the samples reacted in 20% sodium hydroxide, the substituents are introduced not only in amorphous regions but also in crystalline regions to make them disordered. Although spacing between (101) planes does not change, spacing between (101) planes increases by the reaction in 20% sodium hydroxide. Comparing crystallite sizes normal to (hkl) planes under dry conditions with those under wet conditions, it is supposed that cohesive forces between (101) planes are different from those between (101) planes, and the former is hydrogen bonds and the latter resemble Van Der Waals forces. As a result, carbamoylethyl and carboxyethyl groups are introduced selectively between (101) planes.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1979.070240415
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