Cellulose amorphous, alkaline degradation

In the present study, the role of cellulose physical structure in alkaline reactions was investigated by comparing the alkaline degradation of highly crystalline (cellulose I) fibrous hydrocellulose with that of amorphous (noncrystalline) hydrocellulose. The amorphous substrate was taken as a cellulose model the reactivity of which would most closely approximate that of alkali-soluble cellulose. The availablity of such an approximation to the inherent reactivity of cellulose allowed evaluation of the effects of the more highly ordered structure of the fibrous hydrocellulose. 

Experimental Approach. The experimental study was a comparison of the alkaline degradations of fibrous and amorphous hydrocelluloses in oxygen-free 1.0 NaOH, at 60 and 80 C. The fibrous hydrocellulose was predominantly crystalline (cellulose I) and therefore served as a substrate which would undergo alkaline reactions with significant physical structure effects. In contrast, the amorphous hydrocellulose was noncrystalline (9,10). Thus, it was a substrate which would experience substantially less structural constraint during its alkaline reactions. 

Effect of Fiber Degradation on the Corrosion Solution. Hydrolysis and oxidation of protein and cellulose have been described in the literature primarily with the focus on degradation in industrial processing conditions. In alkaline conditions, amino acids are released from silk in a chain unzipping mechanism in acidic conditions, the scissions are random (8,9). As the polymer deteriorates, free carboxyl and amine end groups are formed. Tyrosine oxidizes to a quinone this reaction gives aged silk its yellow coloration. Amorphous areas of the fiber are attacked first. 

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