Compositions of flame retardants and methods of enhancing char formation in a flame retardant-treated substrate. A base material is combined with a flame retardant to form the flame retardant-treated substrate. The flame retardant contains a sulfur copolymer prepared by the polymerization of sulfur monomers with organic monomers. The flame retardant can be deposited on a surface of the base material, coated on the base material, or mixed into the base material. When the flame resistant substrate is on fire, the flame retardant forms a charring layer on the flame retardant-treated substrate. The charring layer can extinguish and prevent the fire from spreading.

An iterative approach to dynamic covalent polymerizations of elemental sulfur with functional comonomers to prepare sulfur prepolymers that can further reacted with other conventional, commercially available comonomers to prepare a wider class of functional sulfur polymers. This iterative method improves handling, miscibility and solubility of the elemental sulfur, and further enables tuning of the sulfur polymer composition. The sulfur polymers may be a thermoplastic or a thermoset for use in elastomers, resins, lubricants, coatings, antioxidants, cathode materials for electrochemical cells, and polymeric articles such as polymeric films and free-standing substrates.

An iterative approach to dynamic covalent polymerizations of elemental sulfur with functional comonomers to prepare sulfur prepolymers that can further reacted with other conventional, commercially available comonomers to prepare a wider class of functional sulfur polymers. This iterative method improves handling, miscibility and solubility of the elemental sulfur, and further enables tuning of the sulfur polymer composition. The sulfur polymers may be a thermoplastic or a thermoset for use in elastomers, resins, lubricants, coatings, antioxidants, cathode materials for electrochemical cells, and polymeric articles such as polymeric films and free-standing substrates.

Sulfur copolymers having high sulfur content for use as raw materials in 3D printing. The sulfur copolymers are prepared by melting and copolymerizing one or more comonomers with cyclic selenium sulfide, elemental sulfur, elemental selenium, or a combination thereof. Optical substrates, such as films and lenses, are constructed from the sulfur copolymer via 3D printing and are substantially transparent in the visible and infrared spectrum. The optical substrates can have refractive indices of about 1.75-2.6 at a wavelength in a range of about 500 nm to about 8 m.

Sulfur copolymers having high sulfur content for use as raw materials in 3D printing. The sulfur copolymers are prepared by melting and copolymerizing one or more comonomers with cyclic selenium sulfide, elemental sulfur, elemental selenium, or a combination thereof. Optical substrates, such as films and lenses, are constructed from the sulfur copolymer via 3D printing and are substantially transparent in the visible and infrared spectrum. The optical substrates can have refractive indices of about 1.75-2.6 at a wavelength in a range of about 500 nm to about 8 m.

The present invention provides a tread rubber composition that is excellent in wet grip performance during the initial phase of running and tensile properties, and a pneumatic tire including the tread rubber composition. The present invention relates to a tread rubber composition containing: a diene rubber; silica; and sulfur and/or a sulfur-containing compound, the tread rubber composition satisfying the following relationships (1) to (3):

EB/M30050 (1);

M1001.7 MPa (2); and

EB500% (3).

Compositions and methods of producing composite materials for use as a cathode in electrochemical cells. Elemental sulfur is mixed with tungsten sulfide (WS.sub.2) to form a composite mixture. Organic comonomers may be added to the composite mixture. The composite mixture is reacted to form the composite material. Electrochemical cells with cathodes containing the composite material demonstrated improved battery performance.

Compositions and methods of producing composite materials for use as a cathode in electrochemical cells. Elemental sulfur is mixed with tungsten sulfide (WS.sub.2) to form a composite mixture. Organic comonomers may be added to the composite mixture. The composite mixture is reacted to form the composite material. Electrochemical cells with cathodes containing the composite material demonstrated improved battery performance.

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 solubilising/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, H.sub.2S donors and antimicrobial materials.

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 solubilising/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, H.sub.2S donors and antimicrobial materials.