POLYMER-GRAFTED CELLULOSE FIBERS .2. POLYMER LOCALIZATION AND INDUCED ALTERATIONS IN FIBER MORPHOLOGY

摘要

In methyl acrylate- or acrylonitrile-grafted northern softwood Kraft or southern softwood Kraft pulp fibers, polymer grafts are present almost homogeneously throughout the fiber wall, although some surface enhancement is observed. On unhydrolyzed fiber surfaces, acrylonitrile grafts protrude in clumps of tangled polymer tufts whereas methyl acrylate grafts form a more uniform; sometimes knobby surface coating. Grafting followed by hydrolysis causes extensive lengthwise splits in the S1 layer, which pulls away from the S2 layer. In the hydrolyzed solvent-dried fiber, the internal grafted polymer/cellulose domains create a unique filamentous and lamellar periodic substructure in the S2 wall. Coexisting with this substructure are numerous microvoids and occasional large pores. WE! believe that the enhanced absorbency of these fibers can be attributed to the S1 layer disruption, the presence of osmotically active polymer (sodium polyacrylate) incorporated extensively within the S2 wall, and the presence of a drastically altered, more accessible S2 wall substructure. Analytical electron microscopy is shown to be a useful technique for investigating polymer grafts in cellulose fibers. (C) 1997 John Wiley & Sons, Inc. [References: 32]