Brightness Reversion of Mechanical Pulps VII: Photostabilization Studies of Thiol Additives for Ligniocellulosic Materials

ABTRACT

The chemical mechanisms contributing to the photostabilization properties of 1-thioglycerol and 2-mercaptoethyl ether for lignocellulosic materials was studied. The thio-additives were impregnated onto woodbased fibers, photolyzed, extracted, and characterized spectroscopically. Both thio-additives were shown to yield the corresponding disulfide when the photolysis experiments were performed on bleached chemithermomechanical pulp (BCTMP). Irradiation of BCTMP fibers impregnated with 2-mercaptoethyl ether under an argon atmosphere yielded only starting material indicating that the thio-additive scavenges radicals generated after the initial photochemical reactions that contribute to the photo-discoloration of wood-based materials.