Brightness Reversion of Mechanical Pulps. X. Photoreversion Fiber Topochemistry

The topochemistry of thiol-photostabilization of hardwood BCTMP (bleached chemithermomechanical pulp) was investigated by scanning electron microscopy (SEM). Employing advanced SEM methods, the location of unextractable sulfur across the fiber wall was determined for post-photolyzed BCTMP fibers. These studies illustrate that thio additives remove chromophores across the fiber wall.