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:
Kinetic studies of swelling of cotton cellulose with 75% (w/w) EDA solution have been carried out. Three rates of the reaction were observed in the temperature range 10-35°C: first, the very fast rate (k1) lasting for about 10 s; second, the extremely slow rate (k2) lasting for 30-50 s; and third, once again a fast rate (k3), k1 being faster than k3. k1 was attributed to the swelling action of EDA-monohydrate in amorphous regions of cellulose; k2 was assigned to the penetration of swelling species into crystallities accompanied by breakage of H bonds in these regions; and k3 was assigned to the opening up of the crystallites. Activation energy values confirmed this trend. At higher temperatures (35-55°C), the middle rate k2 merged with k3, giving only two rates, k1 and k2+3, as the higher temperatures brought about simultaneous diffusion of swelling agent into, and decrystallization of, the crystalline portions of cellulose. EDA solution of 65% (w/w) concentration gave only two rates: the initial fast rate assigned to the swelling of the amorphous portion, followed by a slow one, operating in mesomorphous regions of cellulose, without any appreciable decrystallization. This was atributed to the important fact, viz., the absence of EDA-monohydrates in the solution.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1983.070280710
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