On the Viscoelastic Segment Size of Cellulose

抄録

Dynamic birefringence and viscoelasticity of cellulose acetate propionate were measured at various temperatures covering a wide frequency region from the rubbery plateau to the glassy zone in order to determine the viscoelastic segment size of cellulose. The complex Young's modulus was separated into two components, R and G components. From the limiting modulus at high frequencies of the R component, molecular weight of viscoelastic segment was determined as 3100. This value is the largest one among amorphous polymers previously determined. Larger dynamic segment size reflects the rigid chain structure of β linked D-glucose units (about 10 glucose units per segment). Number of segments per entanglement strand was also estimated to be 4. Reflecting the small segment number per entanglement strand, most of reorientation of segment (relaxation of stress) was found to be delayed until the terminal flow zone.