Methods of forming a polyarylene sulfide and systems as may be utilized in carrying out the methods are described. Included in the formation method is a filtration process for treatment of a mixture, the mixture including a polyarylene sulfide, a salt byproduct of the polyarylene sulfide formation reaction, and a solvent. The filtration process includes maintaining the downstream side of the filter medium at an increased pressure. The downstream pressure can such that the boiling temperature of the mixture at the downstream pressure can be higher than the temperature at which the polyarylene sulfide is insoluble in the solvent.

Methods of forming a polyarylene sulfide and systems as may be utilized in carrying out the methods are described. Included in the formation method is a filtration process for treatment of a mixture, the mixture including a polyarylene sulfide, a salt byproduct of the polyarylene sulfide formation reaction, and a solvent. The filtration process includes maintaining the downstream side of the filter medium at an increased pressure. The downstream pressure can such that the boiling temperature of the mixture at the downstream pressure can be higher than the temperature at which the polyarylene sulfide is insoluble in the solvent.

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 method for formation of a semi-crystalline polyarylene sulfide is described. The method can include reaction of sulfur-containing monomer with a dihaloaromatic monomer in an organic amide solvent to form a polymer following by combination of the polymer with a crystallization solution. The crystallization solution is pre-heated and the mixture formed is slowly cooled to crystallize the polymer.

A method for formation of a semi-crystalline polyarylene sulfide is described. The method can include reaction of sulfur-containing monomer with a dihaloaromatic monomer in an organic amide solvent to form a polymer following by combination of the polymer with a crystallization solution. The crystallization solution is pre-heated and the mixture formed is slowly cooled to crystallize the polymer.

Process for the preparation of a mercapto-terminated liquid polymer comprising the steps of: a) reacting (para)formaldehyde with a halo-alcohol to form a reaction mixture comprising bis(2-dihaloalkyl)formal and b) reacting the reaction mixture of step a) with either (i) sodium polysulfide or (ii) a combination of sodium hydrosulfide and sulfur, wherein the process is performed in the presence of a branching agent selected from the group consisting of di-aldehydes and their corresponding actetals and hemi-acetals.

Process for the preparation of a mercapto-terminated liquid polymer comprising the steps of: a) reacting (para)formaldehyde with a halo-alcohol to form a reaction mixture comprising bis(2-dihaloalkyl)formal and b) reacting the reaction mixture of step a) with either (i) sodium polysulfide or (ii) a combination of sodium hydrosulfide and sulfur, wherein the process is performed in the presence of a branching agent selected from the group consisting of di-aldehydes and their corresponding actetals and hemi-acetals.

A problem is to provide a method for producing a polyarylene sulfide resin having excellent reactivity to other compounds and resins, such as an impact resistance improver such as an epoxysilane coupling agent, a functional group-containing thermoplastic elastomer, or the like, and also provide a polyarylene sulfide resin composition produced by the production method, not containing chlorine atoms, and having the excellent reactivity. A method for producing a polyarylene sulfide resin includes performing polymerization reaction of a mixture containing a diiodo aromatic compound, a sulfur compound, and a polymerization inhibitor having a specified functional group. The problem can be solved by using a polyarylene sulfide resin composition containing a polyarylene sulfide resin having a specified terminal functional group and iodine atoms within a range of 0.01 to 10,000 ppm relative to the polyarylene sulfide resin.

A problem is to provide a method for producing a polyarylene sulfide resin having excellent reactivity to other compounds and resins, such as an impact resistance improver such as an epoxysilane coupling agent, a functional group-containing thermoplastic elastomer, or the like, and also provide a polyarylene sulfide resin composition produced by the production method, not containing chlorine atoms, and having the excellent reactivity. A method for producing a polyarylene sulfide resin includes performing polymerization reaction of a mixture containing a diiodo aromatic compound, a sulfur compound, and a polymerization inhibitor having a specified functional group. The problem can be solved by using a polyarylene sulfide resin composition containing a polyarylene sulfide resin having a specified terminal functional group and iodine atoms within a range of 0.01 to 10,000 ppm relative to the polyarylene sulfide resin.