Crystallinity and Miscibility of Poly(vinyl isobutyl ether)/Poly(e -Llysine) Blends by Solid State 13C NMR Study by Atsushi ASANO*, Yoshifumi MURATA, and Takuzo KUROTSU
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The relation between crystallinity and miscibility of semicrystalline
polymer blends of poly(vinyl isobutyl ether) (PVIBE) and poly(e -L-lysine) (e -PL) is investigated by 13C cross-polarization with magic-angle-spinning (CPMAS) NMR (nuclear magnetic resonance) and DSC measurements. Analysis of the 1H spin-lattice relaxation curves observed from both PVIBE and e -PL signals, which are indirectly obtained from well-resolved 13C CPMAS NMR spectra, suggested that the domains of e -PL in the blends are in the range of 50–100 nm scale. Two-spin or three-spin models were used to simulate the 1H relaxation curves taking into account the contribution of a 1H spin-diffusion rate between PVIBE and e -PL. Furthermore, it was found that blending e -PL largely influences the crystallinity of PVIBE but that of e -PL is little affected by blending PVIBE except for 10/1 composition. The observed melting point of e -PL shifted towards lower temperature accompanied by PVIBE content. This shift was explained by the Gibbs-Thomson effect that the decrease of thickness of crystalline phase causes the depression of the melting point.
A thermoplastic or an elastic polymer is used widely for
engineering purposes. To improve physical or chemical properties of
polymers for some purposes, we often made use of mixing another polymer to these kinds of engineering polymers. Therefore, instead of synthesize a brand-new polymer with all the properties we want, we try to mix two polymers together to form a blend that we hopefully have some properties of both. Recently, with a raise of public awareness to ecology, engineering polymers tend to be required to have properties of eco-friendliness, especially when out of use.
e-Journal of Soft Materials, Vol. 3, pp. 1–8 (2007)
http://www.jstage.jst.go.jp/article/ejsm/3/0/3_1/_article
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