PNIPAM was grafted onto cellulose nanofibers and the temperature response rate was improved by increas-ing the gel surface area and decreased the volume size. The optimum reaction conditions for PNIPAM grafting were as follows: the reaction temperature was 40 ℃, the cellulose nanofiber membrane and N- isopropyl acrylamide had mass ratios of m(N)∶m(C)=15.5∶1, initiator concentration 10.5 mmol/L, and reaction time 3 h. Scanning electron micros-copy showed that after the surface of the fiber grafted by NIPAM,there is bonding phenomenon and the surface is rough between the fibers. Infrared spectrum and X ray photoelectron spectroscopy show that NIPAM was grafted successfully of cellulose. DSC showed that when grafting ratio of PNIPAM-g-Cell is 30%, LCST hydrogel increased significantly. Deswelling kinetics showed that the higher grafting rate is, the more sensitive PNIPAM-g-Cell hydrogel is. The greater PNIPAM-g-Cel diffusion signal intensity ratio is.%将聚N-异丙基丙烯酰胺(PNIPAM)接枝到纤维素纳米纤维上,通过增大凝胶比表面积、缩小体积尺寸提高温度响应速度.PNIPAM接枝的最佳反应条件为:反应温度40 ℃、纤维素纳米纤维膜和N-异丙基丙烯酰胺质量比m(N)∶m(C)=15.5∶1、引发剂浓度10.5 mmol/L、反应时间3 h.扫描电子显微镜表明,纤维表面经NIPAM接枝处理后,纤维间出现粘结现象且表面粗糙.红外光谱和X射线光电子能谱表明,PNIPAM成功接枝在纤维素纤维上.差热扫描表明,PNIPAM-g-Cell接枝率为30%时,水凝胶的LCST显著提高.去溶胀动力学表明,接枝率越高,PNIPAM-g-Cell水凝胶越敏感;PNIPAM-g-Cel扩散信号强度比值越大,扩散程度越大.
展开▼
