超声波处理对纤维素碱脲体系溶解性能的影响

采用碱／尿素／水体系、碱／尿素／硫脲／水体系分别制备纤维素溶液，在溶解的不同阶段用超声波进行处理，并利用光学显微镜、偏光显微镜和X射线衍射对溶解效果进行表征。研究结果表明：溶解之前对纤维素原料的超声波处理主要是对纤维形态结构和超分子结构的破坏，略微增大溶解度；溶解过程中对纤维素溶液超声波处理则可以强化润胀，促进分散，显著增大纤维素的溶解度；在碱／尿素／水体系中超声波对溶解的促进作用强于在碱／尿素／硫脲，水体系中。

Solubility Properties of Cellulose Treated by Ultrasonic in NaOH/Urea Solvent System

The cellulose solutions were prepared in NaOH/Urea/H2O and NaOH/Urea/Thiourea/H2O solvent system and treated by ultrasonic in different dissolving stage. The effect of the dissolution of cellulose was characterized by optical microscope, polarization microscope and X-ray diffraction. When the cellulose material was treated by ultrasonic before the dissolving process, the molecular structure and morphology of cellulose fiber changed a lot while the solubility of cellulose increased slightly. However, the solubility of cellulose increased significantly when the ultrasonic treatment was conducted during the dissolving process. The reason may be that ultrasonic had a synergistic promoting effect which including strengthening the swelling cellulose and promoting the dispersion on dissolving process. The improvement of cellulose solubility in NaOH/Urea/H2Owas greater than that in NaOH/Urea/Thiourea/H2O with the same ultrasonic treatment.