A composition comprising an ethylene/CO interpolymer, formed from a high pressure, free-radical polymerization, and wherein the ethylene/CO interpolymer has the following properties: a) a CO content from “greater than 0” weight percent to less than, or equal to, 10 weight percent CO (carbon monoxide), based on the weight of the interpolymer; and b) a melting point, Tm, in ° C. that meets the following relationship: Tm (° C.)≤601.4*(Density in g/cc)−452.5(° C.).