کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5178156 | 1502490 | 2017 | 8 صفحه PDF | دانلود رایگان |
- Changes in birefringence (ÎnNC) of nanocomposite (NC) gels upon stretching were investigated.
- The variations of ÎnNCs indicate unidirectional and plane-orientations of clay platelets in NC gels.
- The percentage plane-orientation was evaluated for NC gels with different clay content.
- The effects of water content and recovery process on the ÎnNC-strain curves were also clarified.
Changes in the birefringence (ÎnNC) of nanocomposite (NC) gels upon stretching and recovery were investigated for gels comprising a poly(N-isopropylacrylamide)âclay network structure. Irrespective of the composition of the NC gels, a change in the birefringence appeared upon stretching; ÎnNC varied greatly depending on the clay and water contents (Cclay and Cw, respectively) of the gels and the stretching ratio. The NC gels with low Cclay gave rise to unique ÎnNC vs. strain curves with a maximum ÎnNC. For samples with higher Cclay, the variation of ÎnNCs observed in the edge- and through-directions, which is attributed to plane-orientation of the clay platelets, increased with increasing Cclay. This was confirmed by scanning electron microscopy observation, and the percentage plane-orientation was evaluated from the ÎnNC data. On recovery of the strain, the plane-oriented clay platelets underwent minimal reversion to the original state, although most of the PNIPA chains reverted to the random conformation. The effects of Cw on the ÎnNC-strain curves were also clarified.
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Journal: Polymer - Volume 116, 5 May 2017, Pages 439-446