The surface modification by carboxyl ionic liquid for mesoporous silica and the preparation of composite polymer electrolyte with the modified mesoporous silica

A modified mesoporous silica was prepared by esterification reaction of the hydroxyl group on the surface of mesoporous silica with 1-carboxymethyl-3-methyl imidazolium bis(trifluoromethylsulfonate)imine ([(HOOC)C1C1Im][NTf2]). The esterification reaction and structure of the modified mesoporous silica were investigated using the X-ray photoelectron spectroscopy, Nitrogen adsorption–desorption analysis, Transmission electronic microscopy, Field emission scanning electronic microscopy, Energy dispersive X-ray spectroscopy, and Thermogravimetric analysis.The analysis results indicated that the carboxyl group of [(HOOC) C1C1Im] [NTf2] can occur the catalytic esterification reaction with the hydroxyl group on the surface of mesoporous silica and the introduction of ILs did not affect the long range ordered pore structure of mesoporous silica, and the modified mesoporous silica contains 8.14% (wt.) of [(HOOC)C1C1Im][NTf2]. In addition, a composite polymer electrolyte (CPE) was prepared through introducing the modified mesoporous silica and bis (trifluoromethanesulfon) imide lithium salt (LiTFSI) into the carboxylate butadiene-acrylonitrile rubber (XNBR) matrix and the ionic conductivity and mechanical properties of the CPE were studied. The results showed that the mechanical properties and ionic conductivity of the CPE were obviously improved by filling the modified mesoporous silica. When loading 20 phr modified mesoporous silica, the tensile strength was increased to 6.2 MPa from 2.4 MPa, and that the ionic conductivity at room temperature was increased to 1.5 × 10−5 S/cm from 2.0 × 10−6 S/cm. POLYM. COMPOS., 2017. © 2017 Society of Plastics Engineers