Disclosed is a composition comprising at least one interpolymer dispersed within an aqueous medium, the interpolymer comprising at least one unsaturated monomer and at least one selected from the group consisting of at least one conjugated acid, at least one mono-ester of a conjugated acid, and mixtures thereof, and, optionally, at least one surfactant configured to stabilize the interpolymer within the aqueous medium. The conjugated acid may be derived from a naturally-occurring oil, such as tung oil. There is also provided a method for preparing a composition, comprising forming an interpolymer comprising the at least one unsaturated monomer and the at least one selected from the group consisting of at least one conjugated acid, at least one mono-ester of a conjugated acid, and mixtures thereof. There is still further provided a pressure sensitive adhesive comprising the composition prepared according to the disclosed method.