Cotton linters were partially hydrolyzed in dilute acid and the morphology of remaining macrofibrils was studied with scanning electron
microscopy (SEM) under various magnifications. The crystalline region in cellulose is composed of microfibril bundles instead of
separated microfibrils. These microfibril bundles in the macrofibrils were exposed by removing amorphous cellulose on and near the surface
of the macrofibers. XRD suggests that the microfibril bundles have diameters of 20–30 nm. Cellulose apparent crystallinity was not
altered by hydrolysis, as indicated by XRD and NMR results. These facts suggest that amorphous cellulose in the bulk (not on the surface)
is not accessible to hydrolysis and that microfibril bundles are hydrolyzed through a surface reaction process. The observed agglomerization
of macrofibers could be the result of the high surface potential from the remaining microfibrils or acid catalyzed
intermolecular surface dehydration between macrofibrils.