Linear poly(ethylenimine) (LPEI) is an NH-containing analog of poly(ethylene oxide) (PEO). Various groups (e.g. CH3) can be attached to the nitrogen atoms in order to decrease the crystallinity and eliminate hydrogen bonding of the host polymer. This paper focuses on linear poly(N-methylethylenimine), LPMEI, with dissolved lithium triflate (LiTf) and sodium triflate (NaTf). These electrolytes were investigated using infrared spectroscopy, differential scanning calorimetry (DSC), and impedance measurements of the conductivity. A spectroscopic comparison of LPMEI containing LiTf and NaTf over a composition range of 5:1 to 20:1 (nitrogen:cation) shows that contact ion pairs are the predominant species in both systems except for the 5:1 NaTf sample, where the “free” triflate ions are the predominant species. Furthermore, there is an increase in the degree of ionic association with increasing salt concentration in the LiTf systems. The effect of salt concentration on the glass transition temperature (Tg) of the polymer host was examined using DSC. In LPMEI, Tg occurs at −91°C and increases to 3°C at a 5:1 (N:Li) composition. Conductivity measurements of the LPMEI:LiTf system over a composition range of 5:1 to 20:1 are compared with the LPEI:LiTf systems for temperatures between 25 and 60°C. In addition, X-ray powder diffraction (XRD) show a significant presence of crystalline domains in the LPMEI:NaTf samples.

Linear poly(ethylenimine) (LPEI) has been modified by reductive alkylation to form linear poly(N-(2-(2-methoxyethoxy)ethyl)ethylenimine) (LPEI-G2) as verified by nuclear magnetic resonance spectroscopy (NMR). The resulting LPEI-G2 has short methyl-capped oligo(ethylene oxide) side-chains attached to the LPEI backbone. Characterization of pure LPEI-G2 and LPEI-G2 complexed with lithium triflate (LiTf) was carried out over a variety of concentrations using infrared (IR), differential scanning calorimetry (DSC), and impedance techniques. Initial spectroscopic studies indicated that at a 20:1 oxygen atom to lithium ion ratio, “free” ions are the dominant triflate species present. At the same composition, the electrolyte has a Tg of −60°C and a conductivity 7×10−5 S cm−1 at 60°C. The vibrational spectra and conductivity values of samples at O:Li compositions of 20:1 and 5:1 will be discussed.

The age-old turpentine industry is being modernized by a three-fold research attack involving advances in extraction techniques through chemical stimulation procedures; the selection, breeding and propagation of high-yielding turpentine pines; and engineering research on equipment used in woods operations.

American Journal of BotanyVolume 28, Issue 2 p. 175-177 Article POLLEN LONGEVITY OF PINUS STROBUS AND PINUS RESINOSA AS CONTROLLED BY HUMIDITY AND TEMPERATURE John W. Duffield, John W. Duffield Northeastern Forest Experiment Station, Forest Service, U. S. Department of Agriculture, New Haven, ConnecticutMaintained in cooperation with Yale University.Search for more papers by this authorAlbert G. Snow Jr, Albert G. Snow Jr Northeastern Forest Experiment Station, Forest Service, U. S. Department of Agriculture, New Haven, ConnecticutMaintained in cooperation with Yale University.Search for more papers by this author John W. Duffield, John W. Duffield Northeastern Forest Experiment Station, Forest Service, U. S. Department of Agriculture, New Haven, ConnecticutMaintained in cooperation with Yale University.Search for more papers by this authorAlbert G. Snow Jr, Albert G. Snow Jr Northeastern Forest Experiment Station, Forest Service, U. S. Department of Agriculture, New Haven, ConnecticutMaintained in cooperation with Yale University.Search for more papers by this author First published: 01 February 1941 https://doi.org/10.1002/j.1537-2197.1941.tb07957.xCitations: 2 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume28, Issue2February 1941Pages 175-177 RelatedInformation