How might the object-oriented paradigm change the way we teach introductory programming?

There is herein provided a urethane-containing material having one or more moieties of the structure: wherein R is hydrogen, an alkyl, alkenyl or aryl group; wherein X is hydrogen, an alkyl, alkenyl or aryl group, or wherein X is a moiety of the structure: of which R1 and R2 are, each independently, hydrogen, an alkyl, alkenyl or aryl group, or members of a cyclic or heterocyclic group. The urethane-containing material is particularly useful as a low temperature curing agent for active hydrogen-containing compositions.