The grafting reaction of epoxycyclohexyl polyhedral oligomeric silsesquioxanes with carboxylic methoxypolyethylene glycols and the properties of composite solid polymer electrolytes with the graftomer

A novel organic–inorganic hybrid of epoxycyclohexyl polyhedral oligomeric silsesquioxane (e-POSS)–grafted carboxylic methoxypolyethylene glycols (mPEG-COOH), that is, a POSS-mPEG graftomer, was synthesized. The grafting reaction of e-POSS and mPEG-COOH was characterized by Fourier transform infrared (FTIR) and 1H-NMR spectroscopy. Then the graftomer was used to develop new composite solid polymer electrolyte (SPE) films with a carboxylated nitrile rubber–epoxidized natural rubber (XNBR-ENR) self-crosslinked blend system as a dual-phase polymer matrix. The self-crosslinked reaction of the XNBR-ENR matrix was investigated using ATR-FTIR. The morphology of the SPE films and the distribution of lithium salt were investigated using field emission scanning electron microscopy and X-ray diffraction, and the result illustrated that the addition of POSS-mPEG could promote and accelerate the dissociation of LiClO4. The best effect within the range of this study was achieved when 25 phr POSS-mPEG was involved. The differential scanning calorimetry analysis proved that the glass-transition temperature of the composite SPE films was reduced with the increase of POSS-mPEG. The ionic conductivity of the composite SPE films was investigated by electrochemical impedance spectroscopy. The highest ionic conductivity in this study of 2.57 × 10−5 S cm−1 was obtained with 25 phr POSS-mPEG loading. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44460.