This article discusses the enhancement of structure and morphology of PPS fibers by annealing and two zone draw-annealing. Also investigated is the comparison between fiber morphology and properties achieved by single zone draw-annealing vis-a-vis extended annealing and two zone draw-annealing. Annealing of undrawn as-spun fibers yields tenacities around 4.5 gpd (grams/denier). It is shown that when compared with one zone drawing, two zone drawing improves PPS fibers' drawability and enhances the tensile properties significantly. Fibers spun from high molecular weight PPS resins, when drawn and annealed under optimum processing conditions during two zone draw-annealing, possess tenacities around 6 gpd. A model for the fiber structure is proposed based on the morphological studies. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012