Described herein are polyphenylene fibers. The polyphenylene fibers have one or more polyphenylene polymers. The polyphenylene fibers can further include one or more poly(aryl ether sulfone) polymers. In some embodiments, the polyphenylene fibers can have an average diameter that is less than about 1 micron. The polyphenylene fibers can have desirable mechanical properties. Also described herein are methods for forming polyphenylene fibers. In some embodiments, the fibers can be fabricated using specifically engineered polymer solutions in conjunctions with adapted force spinning techniques.

[Problem] To provide: a carbon fiber precursor fiber that can efficiently produce a carbon fiber at a low cost which is excellent in mechanical strengths even without an infusibilization treatment; a carbon fiber; and a method for producing the carbon fiber.

[Solution] A carbon fiber precursor fiber of the present invention includes a polymer containing a constituent unit represented by General Formula (1) below:

##STR00001## where in the General Formula (1), X and Y each independently represent a divalent substituent, a single bond, or a structure forming a fused ring by sharing one side of two adjacent rings, and the divalent substituent is selected from the group consisting of —O—, —S—, —OSO—, —NH—, —CO—, —CH.sub.2—, and —CH(CH.sub.3).sub.2—.

In order to provide a copolymerized polyphenylene sulfide fiber that is thin, has a low heat shrinkage rate, and is suitable for a use as a paper-making binder having excellent weldability, a copolymerized polyphenylene sulfide fiber is characterized by containing a copolymerized polyphenylene sulfide that has a p-phenylene sulfide unit as a main component and contains 3 mol % or more and 40 mol % or less of a m-phenylene sulfide unit in a repeating unit, and having a degree of crystallization of 10.0% or more and 30.0% or less, an average fiber diameter of 5 μm or more and 25 μm or less, and further a shrinkage rate in 98° C. hot water of 25.0% or less.

A material for medical use, which contains nanofibers that are formed from a resin containing a silicone-modified polyurethane resin, and which is characterized in that: the silicone-modified polyurethane resin is a reaction product of (A) a long-chain polyol that has a number average molecular weight of 500 or more, (B) a short-chain polyol that has a number average molecular weight of less than 500, (C) an active hydrogen group-containing organopolysiloxane and (D) a polyisocyanate; and the average fiber diameter thereof is less than 2,000 nm. This material for medical use exhibits excellent performance in a biological test.

The invention relates to a method for the combined processing of at least two polymer melts selected from the group consisting of (M1), (M2) and (M3), wherein (M1) is a polymer melt comprising a terephthalate polyester (A1), (M2) is a polymer melt comprising a copolyester (A2) on the basis of terephthalic acid, at least one aliphatic, ω-dicarboxylic acid and at least one aliphatic 1,ω-diol, and (M3) is a polymer melt 0 comprising a copolyester (A3) on the basis of terephthalic acid, at least one polytetramethylene glycol and at least one aliphatic 1,ω-diol. The method comprises the alternating processing of the at least two polymer melts into at least one product selected from the group consisting of pellets (P1), fibers (P2), expanded particles (P3), preforms (P4) and articles (P5).

The invention relates to a method for the combined processing of at least two polymer melts selected from the group consisting of (M1), (M2) and (M3), wherein (M1) is a polymer melt comprising a terephthalate polyester (A1), (M2) is a polymer melt comprising a copolyester (A2) on the basis of terephthalic acid, at least one aliphatic, ω-dicarboxylic acid and at least one aliphatic 1,ω-diol, and (M3) is a polymer melt 0 comprising a copolyester (A3) on the basis of terephthalic acid, at least one polytetramethylene glycol and at least one aliphatic 1,ω-diol. The method comprises the alternating processing of the at least two polymer melts into at least one product selected from the group consisting of pellets (P1), fibers (P2), expanded particles (P3), preforms (P4) and articles (P5).

The present invention is directed to a reactive dye-dyeable polyurethane-urea elastic yarn including a reaction product of at least two polyols, a diisocyanate compound, a diamine chain extender, an amine chain terminator, and a diethylenetriamine compound, wherein one of the polyols is polyethylene glycol, which is included in an amount of 20 to 30.0 mol % based on the total amount of the polyols, a polyurethane-urea polymer includes 10 meq/kg to 45 meq/kg of primary amine ends, and the capping ratio (CR) of the diisocyanate to the polyols is 1.8 to 2.0.

The present invention is directed to a reactive dye-dyeable polyurethane-urea elastic yarn including a reaction product of at least two polyols, a diisocyanate compound, a diamine chain extender, an amine chain terminator, and a diethylenetriamine compound, wherein one of the polyols is polyethylene glycol, which is included in an amount of 20 to 30.0 mol % based on the total amount of the polyols, a polyurethane-urea polymer includes 10 meq/kg to 45 meq/kg of primary amine ends, and the capping ratio (CR) of the diisocyanate to the polyols is 1.8 to 2.0.

The invention provides an antimicrobial fiber which exhibits excellent antimicrobial properties even without the addition of antimicrobial agents and can remain antimicrobial even after repeated washing. The antimicrobial fiber comprises a fiber having on a surface thereof a polyacetal copolymer (X) containing oxyalkylene groups, the molar amount of oxyalkylene groups in the polyacetal copolymer (X) being 0.2 to 5 mol % relative to the total of the molar amount of oxymethylene groups and the molar amount of oxyalkylene groups.

The invention provides an antimicrobial fiber which exhibits excellent antimicrobial properties even without the addition of antimicrobial agents and can remain antimicrobial even after repeated washing. The antimicrobial fiber comprises a fiber having on a surface thereof a polyacetal copolymer (X) containing oxyalkylene groups, the molar amount of oxyalkylene groups in the polyacetal copolymer (X) being 0.2 to 5 mol % relative to the total of the molar amount of oxymethylene groups and the molar amount of oxyalkylene groups.