No abstract

A broad outline is given of a comprehensive investigation dealing with solid polymeric electrolytes containing ionic species. These materials are based on various types of polyethers (homopolymers, block and graft copolymers) crosslinked via urethane chemistry and either filled with a salt or transformed into ionomers with the anions attached to the chains. The properties studied were specific volume, swelling, glass transition temperature, viscoelasticity, ionic conductivity, transport numbers, magnetic relaxation of nuclei from both the polymer chains and the ions, and redox stability. Mechanisms and models are proposed to explain chain partitioning by cations and the mode of ionic transport. An all‐solid‐state battery was prepared with one of these materials to prove its good performance.

No abstract

Foram preparadas amostras de hidroxietil celulose (HEC) enxertada com poliéteres para aplicação como eletrólitos sólidos poliméricos. Amostras comerciais de HEC foram caracterizadas por ¹H e 13C RMN, FTIR e viscosimetria, visando a determinação dos respectivos graus de substituição molar (MS), grau de substituição (DS) e grau de polimerização (DP). Amostras comerciais de diaminas de poli(óxido de etileno) (POE) e poli(óxido de propileno) (POP) foram também caracterizadas antes de serem convertidas nos correspondentes diisocianatos. As redes foram obtidas através de reações de condensação das HEC com os diisocianatos e caracterizadas por FTIR, UV-Vis, difração de raios-X e análises térmicas, a fim de definir suas Tg.

The viscoelastic behaviour of polyether-based polyurethane networks containing sodium tetraphenylborate was investigated by means of dynamic mechanical measurements. A quantitative analysis of the storage modulus dependence on temperature, frequency, and salt concentration gives rise to three superposition correlations, viz. frequency-temperature, frequencyconcentration, and concentration-temperature. The frequency-temperature superposition follows a WLF behaviour, while the other two are approximately linear expressions particularly well verified in the zone of the transition state, a) Part 1: cf. 14).The present work, based on measurements taken at several frequencies, is an attempt to correlate quantitatively the effect of the main parameters on the storage modulus variation. Experimental PartThe samples examined were the same used previously14) and consisted of poly(ethy1ene oxide) (PEO; M = 400) and poly(propy1ene oxide) (PPO; M = 425) both crosslinked with 4,4',4"methylidynetris(l,4-phenylene) triisocyanate and containing various amounts of sodium tetraphenylborate. Their preparation has already been described14) and their main characteristics are again summarized in Tab. I . Dynamic measurements were carried out on a direct dynamic viscoelastometer (Rheovibron model DDV 11) in the temperature range -50 to 100°C at four frequencies: 3 3 , 1 1 , 35, and 110 Hz.