The present invention relates to an energy saving method for separating an unreacted monomer, by which an unreacted monomer may be easily recovered from a mixture solution including an unreacted monomer, and a separation system which is capable of performing the method.

Disclosed are porous multi-metal oxide nanotubes and a production method therefor. In one aspect, methods for producing porous multi-metal oxide nanotubes are provided comprising: (a) preparing an admixture comprising metal-acetylacetonate precursors, polyacrylonitrile (PAN) and a solvent component; and (b) producing a nanocomposite from the admixture, wherein metals of the metal-acetylacetonate precursors comprise a non-radioactive alkali metal stable isotope and a non-radioactive alkaline earth metal stable isotope. As such, porous multi-metal oxide nanotubes having a single-phase multivalence may be obtained in high yield without using harmful chemical substances. In addition, the polymer electrolyte membrane including the porous multi-metal oxide nanotubes may have maintained and improved mechanical strength, and thus may have maintained durability even during cell operation and may also have improved proton conductivity even at low humidity. The fuel cell including the polymer electrolyte membrane may have improved performance.

A flame-retardant fiber composite includes an acrylic fiber A containing an acrylic copolymer and an aramid fiber. The acrylic fiber A is substantially free of an antimony compound, and the flame-retardant fiber composite forms a surface-foamed char layer when burned. A flame-retardant work clothing includes the flame-retardant acrylic fiber. A highly flame-retardant fiber composite and highly flame-retardant work clothing include an acrylic fiber, and are capable of exhibiting high flame retardancy while suppressing environmental impacts caused by a flame retardant.

In one or more embodiments, the present invention relates to a resin composition containing at least a polymer (A) and a polymer (B), in which the polymer (A) is a polymer that includes one or more monomers selected from the group consisting of acrylonitrile, vinyl halides, and vinylidene halides, the polymer (B) is a polymer that is soluble in benzyl alcohol, and the resin composition contains the polymer (A) in an amount of 70 parts by mass or more and 92.5 parts by mass or less, and the polymer (B) in an amount of 7.5 parts by mass or more and 30 parts by mass or less, where a total amount of the polymer (A) and the polymer (B) is 100 parts by mass. Provided are synthetic fibers that are easily dyeable with an acidic dye without requiring use of a special facility or heating to high temperatures.

The present invention provides a porous carbon fiber which has an excellent permeation amount and excellent pressure resistance, which is prevented from the occurrence of detachment or cracking at an interface, and which can exhibit excellent properties needed for use as a support for a fluid separation membrane. The present invention is a porous carbon fiber having a bicontinuous porous structure, wherein

the average value R.sub.ave of the R value of the outer surface and the R value of the inside is 1.0 or more and 1.8 or less,

the absolute value ΔR of the difference between the R value of the outer surface and the R value of the inside is 0.05 or less, and

R value is a carbonization progression degree calculated from a Raman spectrum in accordance with the following formula:

R value=(intensity of scattering spectrum at 1360 cm.sup.−1)/(intensity of scattering spectrum at 1600 cm.sup.−1).

The present invention provides a porous carbon fiber which has an excellent permeation amount and excellent pressure resistance, which is prevented from the occurrence of detachment or cracking at an interface, and which can exhibit excellent properties needed for use as a support for a fluid separation membrane. The present invention is a porous carbon fiber having a bicontinuous porous structure, wherein

the average value R.sub.ave of the R value of the outer surface and the R value of the inside is 1.0 or more and 1.8 or less,

the absolute value ΔR of the difference between the R value of the outer surface and the R value of the inside is 0.05 or less, and

R value is a carbonization progression degree calculated from a Raman spectrum in accordance with the following formula:

R value=(intensity of scattering spectrum at 1360 cm.sup.−1)/(intensity of scattering spectrum at 1600 cm.sup.−1).

The present invention relates to a fabric containing a modacrylic fiber A and a cellulosic fiber, wherein the modacrylic fiber A contains an infrared absorber inside the fiber, and the fabric is dyed with at least a yellow cationic dye, a yellow reactive dye, and a yellow disperse dye. The fabric can be produced by dyeing a fabric containing a modacrylic fiber A and a cellulosic fiber with a cationic dye, a reactive dye, and a disperse dye to exhibit a fluorescent yellow color. Accordingly, it is possible to provide a fabric with excellent arc resistance and visibility, a method for producing the same, and a clothing item using the same.

The present invention relates to a fabric containing a modacrylic fiber A and a cellulosic fiber, wherein the modacrylic fiber A contains an infrared absorber inside the fiber, and the fabric is dyed with at least a yellow cationic dye, a yellow reactive dye, and a yellow disperse dye. The fabric can be produced by dyeing a fabric containing a modacrylic fiber A and a cellulosic fiber with a cationic dye, a reactive dye, and a disperse dye to exhibit a fluorescent yellow color. Accordingly, it is possible to provide a fabric with excellent arc resistance and visibility, a method for producing the same, and a clothing item using the same.

A method for producing polyacrylonitrile (PAN) fiber, the method comprising: (i) mixing PAN with an ionic liquid in which the PAN is soluble to produce a PAN composite melt in which the PAN is dissolved in the ionic liquid; (ii) melt spinning the PAN composite melt to produce the PAN fiber; and (iii) washing the PAN fiber with a solvent in which the ionic liquid is soluble to substantially remove the ionic liquid from the PAN fiber. Also described herein is a method for producing carbon fiber from the PAN fiber as produced above, the method comprising oxidatively stabilizing the PAN fiber produced in step (iii), followed by carbonizing the stabilized PAN fiber to produce the carbon fiber. The initially produced PAN fiber, stabilized PAN fiber, resulting carbon fiber, and articles made thereof are also described.

A method for producing polyacrylonitrile (PAN) fiber, the method comprising: (i) mixing PAN with an ionic liquid in which the PAN is soluble to produce a PAN composite melt in which the PAN is dissolved in the ionic liquid; (ii) melt spinning the PAN composite melt to produce the PAN fiber; and (iii) washing the PAN fiber with a solvent in which the ionic liquid is soluble to substantially remove the ionic liquid from the PAN fiber. Also described herein is a method for producing carbon fiber from the PAN fiber as produced above, the method comprising oxidatively stabilizing the PAN fiber produced in step (iii), followed by carbonizing the stabilized PAN fiber to produce the carbon fiber. The initially produced PAN fiber, stabilized PAN fiber, resulting carbon fiber, and articles made thereof are also described.