The ball‐milling of cellulose fibers and recrystallization effects

Abstract

Abstract A study has been made of the effect of fine structure on the decrystallization process which results from the ball‐milling of cellulose. The rate of decrystallization is sensitive to the type of fine structure and is accelerated by the presence of moisture. The extent of chain degradation was greater in air atmosphere than in carbon dioxide, suggesting that mechanically induced free radical degradation occurs along with other chain‐breaking processes. A study of the density and moisture regain of the samples after various times of milling showed that a linear relation between regain and density held over the entire range studied. The relation was the same for native and regenerated cellulose. The process of recrystallization of the ball‐milled samples was studied under various conditions and compared to the hydrolytically induced recrystallization of rayons. The type of lattice which develops on recrystallization was found to depend on the original lattice, the extent of ball‐milling and the conditions of recrystallization. A highly ball‐milled sample could be made to recrystallize as cellulose I, II, or IV depending on the conditions.