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 water absorbency of a bleached softwood kraft pulp, as measured by its water retention value (WRV), was increased up to 30 times by graft polymerizing polyacrylonitrile (PAN) and subsequently hydrolyzing it to sodium polyacrylate-polyacrylamide copolymer. WRV was found to be related to the initial PAN graft level rather than to the final sodium polyacrylate content, and was independent of the grafting process used. However, the ceric ion process was found superior to both the cellulose xanthate-H2O2 and ferrous ion-H2O2 redox systems in that it occasioned only a minor loss during the hydrolysis stage and the WRV was less affected by drying. The WRV remained constant as pH was lowered from 9 to 5 but dropped to the level of unmodified pulp at pH 3.5 where the sodium salt is fully converted to poly(acrylic acid). Retention of 1% aqueous NaCl was about 60% of the WRV. The swelling properties of the grafted fibers under various conditions appear to be explained by considering the grafting to act in two ways: (a) the introduction of a potentially hydrophilic component capable of generating swelling pressures and (b) the reduction in the cohesion of the fiber by the interposition of graft polymer chains in the fiber structure.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1973.070171017
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