温敏性纤维素/聚N-异丙基丙烯酰胺复合水凝胶的固体核磁共振表征及动力学研究

Solid-state NMR Study on the Dynamics of Thermo-sensitive Cellulose /Poly( N-isopropylacrylamide) Composite Hydrogel

利用半互穿网络方法将具有温度响应的高分子聚N-异丙基丙烯酰胺(PNIPAM)与天然纤维素复合得到温敏性水凝胶.通过固体核磁共振的1H,13C CP/MAS(交叉极化/魔角旋转)和QCP(定量交叉极化)等实验手段对复合凝胶的结构进行了定性及定量研究,并利用固体静态变温核磁共振实验和偶极滤波-自旋扩散实验研究了复合凝胶中PNIPAM分子链段的动力学行为.

The cellulose/poly （N-isopropylacrylamide） （PNIPAM） composite thermo-sensitive hydrogel was prepared by interpenetrating polymer network （IPN） approach. Various solid-state nuclear magnetic resonance （NMR） methods including 13C cross polarization/magic angle spinning nuclear magnetic resonance（ CP/MAS NMR）, 13C quantitative cross polarization（QCP） NMR, static 1H NMR and IH filtering-spin diffusion NMR experiments were performed to analyze the structure, content, property and dynamics of the composite thermosensitive hydrogel. The results show that the cellulose/PNIPAM composite hydrogels have obvious temperature sensitivity. Cellulose molecules are relatively rigid while PNIPAM molecules are flexible. The space between cellulose and PNIPAM chains are very close.