Disclosed is a variable vapor barrier comprising or produced from a composition wherein the composition comprises an ethylene copolymer, a fatty acid, and an additional polymer; the ethylene copolymer comprises repeat units derived from ethylene, a C.sub.3-8 .alpha.,.beta.-ethylenically unsaturated carboxylic acid, and optionally a comonomer; the fatty acid is one or more carboxylic acids having fewer than 36 carbon atoms, or salts thereof; and the additional polymer is present in the from about 30 to about 85%, based on the weight of the composition.