Cellulose degradation in xanthate process

Changes in degree of polymerization (DP) of cellulose during the viscose process were investigated by determining the number average molecular weight (M?_n), weight average molecular weight (M?_ω), and polydispersity (M?_ω/M?_n) giving molecular weight distribution (MWD). In general, a reduction in DP from the pulp stage to the final filament stage was noticed. Maximum degradation was observed to take place during xanthation and not during aging as sometimes claimed. Among the four methods used for gel permeation chromatography (GPC), Universal calibration HDV method, not involving viscosity measurement, gave the best and most reproducible values.