Hemicelluloses were extracted from birch or fir woods (holocelluloses) and their various bleached pulps, and the relation between the crystallinity and the adhesive property was investigated.
The hemicellulose isolated from sulfite pulp, which is inferior in adhesive property, is higher in crystallinity than that from wood or sulfate pulp (Fig. 1 and 2), probably owing to the lower degree of polymerization (Table 1 and 2).
The hemicellulose isolated from sulfate pulp increases in erstallinity as the degree of polymerization clecreases by cooking with sulfite liquor (Fig. 3 and Table 3) and then decreases greatly in the adhesive property (Fig. 4).
The hemicellulose of neutral sulfite semichemical pulp, which is superior in adhesive property, is as lower in crystallinity as that of sulfate pulp (Fig. 5).
It is well-known that the adhesives considerably higher in crystallinity is inferior in adhesive property.These results suggest also the relation between the strength of fiber-to-fiber bond in pulp sheet and the crystallinity of the hemicellulose.