Studies on synthesis of 3-(2-cyano ethoxy) methyl- and 3-[(methoxy-triethylenoxy)] methyl-3'-methyloxetane and their copolymers

The two monomers 3-(2-cyano ethoxy) methyl- and 3-[(methoxy-triethyleneoxy)]-methyl-3'-methyloxetane were prepared from the reaction of 3-methyl-3'-hydroxylmethyl oxetane (HMO) with acrylonitrile and triethylene glycol monomethyl ether, respectively. A novel series of copolymers were synthesized by starting from these two monomers along with BF₃·ether as the catalyst and BDO as the initiator via a cationic ring-opening copolymerization. The GPC analysis presents the number average molecular weight of the copolymers ranging from 2756 to 5342, and polydispersity from 1.26 to 1.83. Regarding the glass transition temperature (T_g), the DSC results imply that these copolymers would have a higher ion inductivity than pure PEG. And the TGA measurements reveal that the copolymers possess a very high heat decomposition temperature. The conductivity of the AN20 at room temperature is about 1.07 × 10^-5 S/cm, while at 353 K is 2.79 × 10^-4 S/cm, approaching the practical requirement of polymer electrolytes for lithium ion batteries.