Crystallization behavior of cellulose in cellulose/NMMO solutions

Abstract

Crystallization of cellulose/NMMO (N-methylmorpholin N-oxide) solutions has been investigated to understand the effects of molecular weight, dope concentration, water content in NMMO and anti-oxidant on the crystallization kinetic of cellulose. From the dynamic crystallization kinetic results, it was verified that crystallization of cellulose in the cellulose/NMMO solution was mainly due to the transcrystallization from the crystallization of NMMO solvent. Consequently, the crystallization rate in the dopes with a higher molecular weight and a higher solution concentration was slower than the dope with a lower molecular weight and lower concentration due to the less formation of NMMO crystallite. The water in NMMO causes the difficulty in the crystallization of NMMO. As a result, the dopes with a higher water content show slow crystallization. It was also found that anti-oxidants for cellulose/NMMO dope acted as the crystallization retarder for cellulose.