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Molecular Characteristics of Poly( N ‐isopropylacrylamide) Separated from Nanocomposite Gels by Removal of Clay from the Polymer/Clay Network
Author(s) -
Haraguchi Kazutoshi,
Xu Yingjia,
Li Guang
Publication year - 2010
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.200900819
Subject(s) - hectorite , polymer clay , nanocomposite , poly(n isopropylacrylamide) , swelling , polymer , hydrofluoric acid , materials science , polymer chemistry , clay minerals , chemical engineering , montmorillonite , chemistry , copolymer , composite material , mineralogy , engineering , metallurgy
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.