Reacting thraustochytrid-derived triglycerides with sulfur provides novel polymer materials and enriched saturated triglycerides. The strategy features sustainable, cultured triglyceride biosynthesis, and a novel divergent processing method to provide saturated triglycerides and functional sulfur polymers. The saturated triglycerides are established precursors to biodiesel. Copolymers made from the reaction of sulfur and unsaturated triglycerides have a number of established uses in energy storage, metal binding, insulation, fertilizers, and more.