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.

A composition of matter having the following chemical structure:

[00001]$.Math.H_x.Math.O_{\frac{\left(x-1\right)}{2}}.Math..Math.Z_y$ wherein x is and odd integer 3; y is an integer between 1 and 20; and Z is one of a monoatomic ion from Groups 14 through 17 having a charge value between 1 and 3 or a polyatomic ion having a charge between 1 and 3.

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.

A method for removing sulfides from an aqueous liquid, wherein the aqueous liquid is contacted with an oxidizer in the presence of fibrous material dyed with at least one sulfur dye or sulfurized vat dye, to convert the sulfides in the aqueous liquid to a non-toxic product.

A method for removing sulfides from an aqueous liquid, wherein the aqueous liquid is contacted with an oxidizer in the presence of fibrous material dyed with at least one sulfur dye or sulfurized vat dye, to convert the sulfides in the aqueous liquid to a non-toxic product.

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.

A composition of matter having the following chemical structure: $\left[\frac{H_x{O}_{\left(x-1\right)}}{2}\right]Z_y$
wherein x is and odd integer 3;
y is an integer between 1 and 20; and
Z is one of a monoatomic ion from Groups 14 through 17 having a charge value between 1 and 3 or a polyatomic ion having a charge between 1 and 3.

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.