Haraguchi Kazutoshi, Xu Yingjia, Li Guang
Material Chemistry Laboratory, Kawamura Institute of Chemical Research, 631 Sakado, Sakura, Chiba 285-0078, Japan.
Macromol Rapid Commun. 2010 Apr 20;31(8):718-23. doi: 10.1002/marc.200900819. Epub 2010 Feb 23.
The extraordinary mechanical and swelling/deswelling properties of nanocomposite (NC) gels are attributed to their unique organic (polymer)/inorganic (clay) network structure. In this study, poly(N-isopropylacrylamide) (PNIPA) was successfully separated from an NC gel network by decomposing the clay (hectorite) using hydrofluoric acid (HF). A very low HF concentration (0.2 wt.-%) was adequate for the decomposition of the clay without causing any damage to PNIPA. The separated PNIPA had a high $\overline M _{\rm w}$ (=5.5 × 10(6) g · mol(-1) ). Also, $\overline M _{\rm w}$ was almost constant regardless of the clay concentration (C(clay) = 1-25 × 10(-2) mol · l(-1) ), even though the properties of the NC gel varied widely over this C(clay) range. Comparisons of NC gels, PNIPA, and SiO(2) -NC gels indicated that the clay platelets specifically play an important role in NC gels.
纳米复合（NC）凝胶非凡的机械性能以及溶胀/消溶胀性能归因于其独特的有机（聚合物）/无机（黏土）网络结构。在本研究中，通过使用氢氟酸（HF）分解黏土（锂蒙脱石），成功地从NC凝胶网络中分离出了聚（N-异丙基丙烯酰胺）（PNIPA）。极低浓度的HF（0.2 wt.-%）就足以分解黏土，且不会对PNIPA造成任何损害。分离出的PNIPA具有较高的$\overline M _{\rm w}$（=5.5×10(6) g·mol(-1)）。此外，尽管在此黏土浓度（C(clay) = 1 - 25×10(-2) mol·l(-1)）范围内NC凝胶的性能变化很大，但$\overline M _{\rm w}$几乎不受黏土浓度的影响。对NC凝胶、PNIPA和SiO(2)-NC凝胶的比较表明，黏土片层在NC凝胶中特别起着重要作用。
