Nuclear magnetic relaxation study of poly(propylene oxide)complexed with lithium salt

✍ Scribed by J.P. Donoso; T.J. Bonagamba; P.L. Frare; N.C. Mello; C.J. Magon; H. Panepucci

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 311 KB
• Volume: 40
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(95)00194-j

✦ Synopsis

Measurements

of 'Li, 'H and 19F

nuclear relaxation times and 'Li linewidths are reported for poly(propylene oxide) complexed with lithium salts (LiClO,, LiBF, and LiAsF,). For PPO,LiBF, and PPO.LiClO, the onset of the 'Li motional line narrowing. occurs at aooroximatelv L. The NMR deco;pling methods was used to eliminate heteronuclear contsbution to 'L;iine shape. it ;as found that the Li-H interaction accounts for 80-90% of the linewidth. The remarkably similar temperature dependence of the measured 'H and 'Li spin-lattice relaxation rates, which shows rate maxima at 340.350 K in this PPO-Li salts complexes, gives additional evidences for correlation between the cationic and the polymeric motions. The nuclear spin-lattice relaxation rates of the PPO complexes always peak at higher temperatures than the POE complexes, suggesting a lower ionic mobility for the former complexes. The frequency dependence of the relaxation rates cannot be described in the framework of the BPP theory.