纤维素/NMMO·H_2O溶液的熔融和固化行为

采用体积膨胀法测定了纤维素/N-甲基吗啉-N-氧化物-水合物（NMMO·H_2O）溶液的比容与温度的关系。根据比容与温度的关系曲线和和差热扫描量热（DSC）曲线研究了NMMO·H_2O和纤维素/NMMO·H_2O溶液体系的熔融和固化行为,并根据比容和DSC曲线分别得到了不同纤维素含量溶液的熔点。结果表明,NMMO·H_2O和纤维素/NMHO·H_2O溶液的比容在固态和液态时均随着温度的升高而增大。NMMO·H_2O和纤维素/NMMO·H_2O溶液的比容升温曲线上在NMMO·H_2O的熔点附近有一个台阶,说明室温下固化的溶液中有NMMO·H_2O结晶态存在。在降温过程中,由于溶液中纤维素分子链的影响,使溶液中的NMMO·H_2O结晶受到影响,并且随着溶液中纤维素质量分数的增加,NMMO·H_2O的结晶过程逐渐减慢,溶液的熔点下降。

Melting and Solidifying Behaviors of Cellulose/N - Methylmorpholine -N-oxide Monohydrate (NMMO.H_2O) Solutions

Dilatometer is used to measure the specific volume of N - methylmorpholine - N - oxide monohydrate ( NMMO .H2O) and cellulose NMMO.H2O solution at different temperature. With specific volume curves and DSC curves of the solutions, the melting and solidifying behaviors are studied and the melting points of NMMO . H2 0 and cellulose NMMO . H2O solutions are measured. It is found that the specific volume increases with temperature increasing in both solid and liquid phase. The steps in the curves of specific volume indicated that there is crystal phase in the solid phase of the solutions . In the cooling process, the crystallizing process of NMMO ?H2 0 molecules is disturbed by the cellulose chains in the solutions. With the cellulose concentration in the solutions increasing, the crystallizing process is delayed and the melting point of the solutions is decreasing.