Sulfur composites and polymeric materials having a high sulfur content and prepared from elemental sulfur as the primary chemical feedstock. The sulfur copolymers are prepared by the polymerization of elemental sulfur with one or more monomers of amines, thiols, sulfides, alkynylly unsaturated monomers, nitrones, aldehydes, ketones, thiiranes, ethylenically unsaturated monomers, or epoxides. The sulfur copolymers may be further dispersed with metal or ceramic composites or copolymerized with elemental carbon, photoactive organic chromophores, or reactive and solubilizing/biocompatible moieties. The sulfur composites and polymeric materials feature the ability self-healing through thermal reformation. Applications utilizing the sulfur composites and polymeric materials may include electrochemical cells, optics, H2S donors and antimicrobial materials.