Wood fiber cellulose portion

In a wood fiber, the cellulose portion of the microfibrils is the only major component found in a crystalline state. A cellulose microfibril is a long thread-like aggregate of cellulose chains of about 200 A wide and a few microns long. 

Two types of wood pulp provided the fibrils used for patching. The first was a moderately beaten wood pulp obtained from the Department of Pulp and Paper Science, North Carolina State University. The second was Cellunier P, a cellulose provided by the ITT Rayonier Company. Portions of the pulp and Cellunier P were dyed with 0.5% Cuprophenyl Navy Blue RL (from the Ciba-Geigy Corporation) and 0.5% tetrasodium phosphate for 30 min at 82°C to provide greater visual contrast between the fibers and the substrates. The wood pulp was diluted with distilled water to form 0.5 and 0.1% slurries. The Cellunier P was diluted to a 0.05% slurry. Both were treated in a blender to separate lumps formed during dyeing. 

Definition Isolated, colloidal crystalline portion of cellulose fibers partially depolymerized acid hydrolysis prod, of purified wood cellulose... 

Synonyms Cellulose gel MCC Dehnition Isolated, colloidal crystalline portion of cellulose fibers partially depolymerized acid hydrolysis prod, of purified wood cellulose Properties Wh. fine cryst. powd., odorless partly sol. with swelling in dil. alkali insol. in water, dil. acids, and most org. soivs. bulk dens. 18-19 Ib/ft ref. index 1.55 pH 5-7 Toxicology LD50 (oral, rat) > 5 g/kg, no significant hazard irritant by inhalation (dust) may be damaging to lungs TSCA listed... 

The raw material for CTA is wood pulp oreotton lintersof high -eellulose content. The term -cellulose refers to the portion of the cellulosic raw material which is insoluble after treatment with an aqueous solution of sodium hydroxide of 17-18%. The acetylation, at least initially, is heterogeneous and topochemical wherein successive layers of cellulose fibers react and are solubilized in the reaetion medium, thus exposing new surfece for reactions. The cellulose fibers are mixed with sulfuric acid as catalyst and suspended in a mixture of aeetic anhydride and acetic acid. The anhydride is used in slight excess compared to the acetic acid. The sulfuric acid reacts with acetic anhydride to form acetylsulfiiric acid. 

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