Provided are a resin including a unit of Chemical Formula 1 and a unit of Chemical Formula 2, a method for preparing the same, a resin composition including the same, and a molded article including the resin composition,

##STR00001## wherein all the variables are described herein.

New block polymers are described, as well as processes for preparing them using ring-opening polymerisation and ring-opening copolymerisation techniques. Also described are electrolytes, cathodes and batteries comprising the polymers.