Provided is a method of making a polymeric composition comprising (a) providing a dispersion of initial polyolefin particles in an aqueous medium, wherein the initial polyolefin particles comprise (i) one or more hydrocarbon polyolefin, (ii) one or more non-hydrocarbon polyolefin, and (iii) one or more crosslinking agent; (b) contacting the initial polyolefin particles with a peroxide initiator to form crosslinked polyolefin particles.