Flowlines for use in oil and gas applications are described. The flowlines include a barrier layer that includes polyarylene sulfide composition that exhibits high strength and flexibility characteristics. Methods for forming the flowlines are also described. Formation methods include dynamic vulcanization of a polyarylene sulfide composition that includes an impact modifier dispersed throughout the polyarylene sulfide. A crosslinking agent is combined with the other components of the composition following dispersal of the impact modifier throughout the composition. The flowlines can include production fluid flowlines, supporting fluid flowlines, bundled flowlines, etc. and can be utilized as risers, pipelines, jumpers, and the like.