A grafted polymer (P(MMA-MAh)-PEGME)) was synthesized by reacting poly(ethylene glycol) monomethyl ether (PEGME) with copolymer of poly(methyl methacrylate-maleic anhydride) (P(MMA-MAh) and end-capping the residual carboxylic acid with methanol. Natural rectorite (REC) was made organophilic by modification with the surfactant dodecyl benzyl dimethyl ammonium chloride. The organoclay was termed OREC and was used as a filler additive to modify gel polymer electrolytes (GPEs) which consisted of the grafted polymer (used as a polymer matrix), propylene carbonate (PC) as a plasticizer and LiClO4 as a lithium ion producer.
The temperature dependence of the ionic conductivity of the GPEs agreed well with the VTF (Vogel-Tamman-Fulcher) relation. 5 phr doses of OREC resulted in the highest ionic conductivity. Using OREC also considerably improved the plasticizer retention levels. As a consequence of OREC occupation of the free volume space in the polymer matrix of GPEs, the bulk resistance of the GPEs was reduced and the glass transition temperature (Tg) increased. From the present research, it can be concluded that the incorporation of PEGME into the copolymer of P(MMA-MAh) produced a great improvement in ionic conductivity, plasticizer retention capability and movement of carrier charge of Li+.