NMMO/纤维素溶液及其再生纤维素聚集态结构的表征

NMMO/cellulose solution and the characterization of its regenerated cellulose aggregation structure

通过偏光显微镜、红外光谱仪和X-射线衍射仪对棉浆粕在4-甲基吗啉-N-氧化物单水化合物(NMMO·H_2O)中的溶解过程及棉浆粕再生纤维素的聚集态结构进行了表征.结果表明:NMMO·H_2O溶解棉浆粕从纤维素无定形区的溶胀开始,结晶区的溶胀、溶解速度较慢,90℃时,1h能完全溶解;再生前后纤维素的一级结构基本不变,溶解过程以物理过程为主,棉浆粕在NMMO·H_2O中溶解再生后发生了晶型的转变,由纤维素Ⅰ转变为纤维素Ⅱ;棉浆粕再生纤维素无定形区纤维素分子链的有序度远低于棉浆粕纤维素分子链的有序度,再生纤维素分子链排列更乱.即使在结晶区,再生纤维素的分子链取向度也低于棉浆粕纤维素结晶区分子链的取向度,棉浆粕纤维素的结晶度为82.71%,棉浆粕再生纤维素的结晶度为27.86%,结晶度显著下降.

The cellulose solution in NMMO·H2O and the aggregation structure of the regenerated cellulose were characterized using polarized optical microscope（POM）,FTIR and XRD.The results showed that dissolving of cotton pulp in NMMO·H2O is starting from swelling of the cellulose amorphous area;the swelling and dissolving of crystallization is slower and can be completely dissolved after 1hat 90℃.The primary structure of cellulose remained after regeneration,which means that the dissolution process is physical process,and the crystal structure of regenerated cellulose changes from celluloseⅠinto cellulose Ⅱ.Orientation degree of regenerated cellulose chain in amorphous area is far lower than that of the cotton pulp,and the arrangement of regenerated cellulose molecular chain is more disorder.Even in the crystalline region,the orientation degree of regenerated cellulose molecule chain in crystalline region is lower than that of cotton pulp fiber.The crystallinity of cotton cellulose and its regenerated cellulose was 82.71% and 27.86%,respectively,so the degree of crystallinity is significantly decreased after regeneration.