【摘要】 利用溴代—接枝两步法将N-异丙基丙烯酰胺(NIPAAm)接枝聚合到纤维素纳米微晶(CNCs)表面，制备得到PNIPAAm改性的CNCs(P-CNCs),并将该P-CNCs分散于海藻酸钠(SA)基体中，得到复合水凝胶薄膜。对改性P-CNCs进行了结构和性能的表征，并研究了P-CNCs的温度响应特性对复合水凝胶薄膜分子透过性能影响。结果表明，改性P-CNCs保持了棒状结构但相比于CNCs直径变大，晶型保持不变但是结晶度降低。当环境温度高于低临界转变温度(LCST)时，P-CNCs悬浮液的透光率增大。添加P-CNCs制备的复合水凝胶薄膜，其热稳定性相比与其他水凝胶薄膜有所提高。当环境温度≥LCST时，添加P-CNCs的复合水凝胶薄膜的水蒸气透过性相比环境温度25℃时明显提高，300 min后水蒸气透过量相比提高了17%;而相比于添加CNCs的水凝胶薄膜，其相同时间下的水蒸气透过量提高了28.6%。亚甲基蓝分子透过性实验表明，在环境温度≥LCST的条件下，添加P-CNCs的复合水凝胶薄膜其分子透过速度要显著大于添加未改性CNCs的水凝胶薄膜，且分子透过速度随着P-CNCs添加量的增大而增大。更多还原

【Abstract】 N-isopropylacrylamide(NIPAAm) was grafted onto cellulose nanocrystalline(CNCs) surface by bromo-grafting two steps methods, and PNIPAAm-modified CNCs(P-CNCs) were prepared. The P-CNCs were dispersed in sodium alginate(SA) as matrix to obtain composite hydrogel films. The structure and properties of the modified P-CNCs were characterized, and the effect of the temperature-response of P-CNCs on the molecular permeability of the composite hydrogel films was studied. The results showed that the modified P-CNCs maintained a rod-like structure, but the diameter of the modified P-CNCs was larger, and the crystallinity of the modified P-CNCs was reduced. When the ambient temperature was higher than the low critical transition temperature(LCST), the light transmittance of P-CNCs suspension increased. Compared with other hydrogel films, the thermal stability of composite hydrogel films prepared by adding P-CNCs was improved. When the ambient temperature was higher than LCST, the water vapor permeability of the composite hydrogel film with P-CNCs was significantly increased compared with that at 25 ℃, and the water vapor permeability increased by 17% after 300 min. Compared with the hydrogel film with CNCs, the water vapor transmittal increased by 28.6% in the same time. Methylene blue molecular permeability experiments showed that the molecular permeability of the composite hydrogel films with P-CNCs added was significantly higher than that with unmodified CNCs added at ambient temperature ≥LCST, and the molecular permeability increased with the increase of P-CNCs added.更多还原