Preparation, structure, and properties of melt spun cellulose acetate butyrate fibers

The melt spinning of cellulose acetate butyrate (CAB) without any additives is realized according to the thermal and rheological properties of cellulose acetate butyrate raw material. Thermogravimetric analysis reveals that thermal degradation of cellulose acetate butyrate occurs at 275℃ in oxygen. Rheological tests show that cellulose acetate butyrate is a strong shear thinning pseudoplastic fluid. The melt viscosity of cellulose acetate butyrate is found to be relatively sensitive to temperature change and cellulose acetate butyrate melt is difficult to flow until the temperature reaches 230℃. However, thermal degradation of cellulose acetate butyrate during spinning cannot be completely avoided even when the spinning temperature is 230℃. The orientation of cellulose acetate butyrate fibers can be improved by increasing the spinning draw ratio during the spinning process or by hot drawing during the drawing process. Crystallization of cellulose acetate butyrate fibers is facilitated by improving molecular orientation. Owing to the improved orientation and crystallinity, the tensile strength and initial modulus of cellulose acetate butyrate fibers are enhanced. The cellulose acetate butyrate fiber achieves the highest degree of orientation and crystallinity by drawing at 135℃, showing the highest tensile strength at 1.42 cN/dtex. Moreover, dyeing experiments show that the cellulose acetate butyrate fiber can be dyed with a disperse dye and the suitable dyeing temperature is in the range of 80∼90℃.