Abstract: A method of preparing a carbon fiber including: preparing a precursor fiber for preparing a carbon fiber; and stabilizing the precursor fiber. The stabilization of the precursor fiber includes a first stabilization phase, a second stabilization phase, a third stabilization phase, and a fourth stabilization phase, which are set at four different temperatures between a temperature at which heat starts to be generated from the stabilization reaction of the precursor fiber and a temperature at which the generation of heat is maximized. Ozone gas is input while at least one phase of the third stabilization phase and the fourth stabilization phase is carried out.

Abstract: A storage device includes a printed circuit board (PCB) with attached semiconductor chips, each including a memory, and with at least one wire coupling the semiconductor chips. The storage device includes a case including a first case surrounding a top portion of the printed circuit board and a second case surrounding a bottom portion of the printed circuit board. A sidewall of the first case and a protrusion of the second case form a concavo-convex structure. The sidewall of the first case and the protrusion of the second case cover a side of the printed circuit board.

Abstract: Provided is a method of preparing an acrylonitrile-based copolymer for a carbon fiber, which comprises: preparing a reaction solution including a monomer mixture comprising a sulfonate-based monomer represented by Chemical Formula 1, a carboxylic acid-based monomer, and an acrylonitrile-based monomer and an organic solvent; and subjecting the reaction solution to polymerization, wherein the monomer mixture comprises the sulfonate-based monomer represented by Chemical Formula 1 at 0.55 to 1.6 mol %.

Abstract: The present disclosure relates to an organic-inorganic hybrid polyolefin composite and a preparation method of the same.

Abstract: The present invention relates to a dispersion device and a defoamation device comprising the same, which provides a dispersion device comprising a dispersion plate equipped with an inclined surface extended downwards obliquely and raw material inflow nozzles formed on the inclined surface to introduce a raw material into the inclined surface; and a band spaced apart from the inclined surface of the dispersion plate to form a gap from the inclined surface, thereby being configured so that the raw material flows through the gap.

Abstract: The present invention relates to a method for producing a polyacrylonitrile-based fiber, wherein the method polymerizes a monomer mixture including an acrylonitrile-based monomer, a carboxylic acid-based comonomer, and an acrylate-based comonomer, wherein the acrylate-based comonomer includes the steps of producing a polyacrylonitrile-based copolymer so as to be included in an amount of 4 to 20 parts by weight based on 100 parts by weight of the monomer mixture, fiberizing the polyacrylonitrile-based copolymer, oxidizing and stabilizing the fiberized polyacrylonitrile-based copolymer, which may control the oxidation stabilization reaction, particularly the cyclization reaction. Accordingly, the energy consumption of the oxidation stabilization reaction may be reduced, economical efficiency of the production of polyacrylonitrile-based fiber may be obtained, and the physical and mechanical properties of the carbon fiber may be improved.

Abstract: A method of preparing an acrylonitrile-based copolymer for a carbon fiber. The method includes: preparing a reaction solution including a (meth)acrylonitrile-based monomer and a first reaction solvent; adding a first portion of a radical polymerization initiator to the reaction solution to initiate polymerization; and adding a second portion of the radical polymerization initiator to the reaction solution when a polymerization conversion ratio is between 70 to 80%.

Abstract: The present invention relates to a method for producing an acrylonitrile-based fiber, the method including: providing a polymer solution including an acrylonitrile-based copolymer containing a carboxylic acid group; mixing 100 parts by weight of the polymer solution with 1 to 6 parts by weight of a hydrophilization solution containing an organic solvent and ammonia water in a weight ratio of 95:5 to 60:40 to prepare a spinning stock solution; and spinning the spinning stock solution. The method controls the viscosity of the spinning stock solution to improve the stretchability and strength of the acrylonitrile-based fiber, and suppresses the occurrence of gelation.

Abstract: Provided is a method of preparing an acrylonitrile-based copolymer for a carbon fiber, which comprises: preparing a reaction solution including a monomer mixture comprising a sulfonate-based monomer represented by Chemical Formula 1, a carboxylic acid-based monomer, and an acrylonitrile-based monomer and an organic solvent; and subjecting the reaction solution to polymerization, wherein the monomer mixture comprises the sulfonate-based monomer represented by Chemical Formula 1 at 0.55 to 1.6 mol %.

Abstract: Provided is an acrylonitrile-based copolymer for a carbon fiber which includes a sulfonate-based monomer unit, a carboxylic acid-based monomer unit, and an acrylonitrile-based monomer unit, and the acrylonitrile-based copolymer for a carbon fiber includes the sulfonate-based monomer unit at 0.55 to 1.55 mol %, and the carboxylic acid-based monomer unit at 0.60 to 1.40 mol %.

Abstract: The present invention relates to a method of preparing a (meth)acrylonitrile-based polymer for preparing a carbon fiber, which comprises adding a reaction solution comprising a (meth)acrylonitrile-based monomer and a reaction solvent to a reactor to perform solution polymerization, performing solution polymerization under a condition in which a power consumption of the reactor is 1 to 5 kW/m3 when the reaction solution in the reactor has a viscosity of 0.1 poise or more and 250 poise or less, and performing solution polymerization under a condition in which a power consumption of the reactor is 8 to 13 kW/m3 when the reaction solution in the reactor has a viscosity of more than 250 poise and 450 poise or less.

Abstract: A method of preparing a carbon fiber including: preparing a precursor fiber for preparing a carbon fiber; and stabilizing the precursor fiber. The stabilization of the precursor fiber includes a first stabilization phase, a second stabilization phase, a third stabilization phase, and a fourth stabilization phase, which are set at four different temperatures between a temperature at which heat starts to be generated from the stabilization reaction of the precursor fiber and a temperature at which the generation of heat is maximized. Ozone gas is input while at least one phase of the third stabilization phase and the fourth stabilization phase is carried out.

Abstract: The present invention relates to a dispersion device and a defoamation device comprising the same, which provides a dispersion device comprising a dispersion plate equipped with an inclined surface extended downwards obliquely and raw material inflow nozzles formed on the inclined surface to introduce a raw material into the inclined surface; and a band spaced apart from the inclined surface of the dispersion plate to form a gap from the inclined surface, thereby being configured so that the raw material flows through the gap.

Abstract: The present invention relates to a method for producing an acrylonitrile-based fiber, the method including: providing a polymer solution including an acrylonitrile-based copolymer containing a carboxylic acid group; mixing 100 parts by weight of the polymer solution with 1 to 6 parts by weight of a hydrophilization solution containing an organic solvent and ammonia water in a weight ratio of 95:5 to 60:40 to prepare a spinning stock solution; and spinning the spinning stock solution. The method controls the viscosity of the spinning stock solution to improve the stretchability and strength of the acrylonitrile-based fiber, and suppresses the occurrence of gelation.

Abstract: The present invention relates to a method for producing a polyacrylonitrile-based fiber, wherein the method polymerizes a monomer mixture including an acrylonitrile-based monomer, a carboxylic acid-based comonomer, and an acrylate-based comonomer, wherein the acrylate-based comonomer includes the steps of producing a polyacrylonitrile-based copolymer so as to be included in an amount of 4 to 20 parts by weight based on 100 parts by weight of the monomer mixture, fiberizing the polyacrylonitrile-based copolymer, oxidizing and stabilizing the fiberized polyacrylonitrile-based copolymer, which may control the oxidation stabilization reaction, particularly the cyclization reaction. Accordingly, the energy consumption of the oxidation stabilization reaction may be reduced, economical efficiency of the production of polyacrylonitrile-based fiber may be obtained, and the physical and mechanical properties of the carbon fiber may be improved.

Abstract: The present invention relates to an apparatus for manufacturing carbon fiber by using microwaves, and more particularly, to an apparatus for manufacturing carbon fiber by using microwaves, which directly or indirectly heats and carbonizes a carbon fiber precursor by using microwaves, so that energy efficiency is improved because an entire carbonization furnace is not heated, and a property of the precursor is adjusted by a simpler method by using microwaves.

Abstract: A method of preparing an acrylonitrile-based copolymer for a carbon fiber. The method includes: preparing a reaction solution including a (meth)acrylonitrile-based monomer and a first reaction solvent; adding a first portion of a radical polymerization initiator to the reaction solution to initiate polymerization; and adding a second portion of the radical polymerization initiator to the reaction solution when a polymerization conversion ratio is between 70 to 80%.

Abstract: The present invention relates to a method of preparing a (meth)acrylonitrile-based polymer for preparing a carbon fiber, which comprises adding a reaction solution comprising a (meth)acrylonitrile-based monomer and a reaction solvent to a reactor to perform solution polymerization, performing solution polymerization under a condition in which a power consumption of the reactor is 1 to 5 kW/m3 when the reaction solution in the reactor has a viscosity of 0.1 poise or more and 250 poise or less, and performing solution polymerization under a condition in which a power consumption of the reactor is 8 to 13 kW/m3 when the reaction solution in the reactor has a viscosity of more than 250 poise and 450 poise or less.

Abstract: A polyolefin has 1) a density in the range of 0.93 to 0.97 g/cm3, 2) a BOCD (Broad Orthogonal Co-monomer Distribution) index defined by a given equation in the range of 1 to 5, and 3) a molecular weight distribution (weight average molecular weight/number average molecular weight) in the range of 4 to 10. A supported hybrid metallocene catalyst comprises a first metallocene compound represented by a first given formulae, a second metallocene compound represented by one of three given formulae, and a support.

Abstract: The present invention relates to a novel metallocene compound, a catalyst composition comprising the same, and to olefinic polymers produced using the same. The metallocene compound according to the present invention and the catalyst composition comprising the same can be used when producing olefinic polymers, have outstanding copolymerization properties, and can produce olefinic polymers of high molecular weight. In particular, when the metallocene compound according to the present invention is employed, highly heat resistant block copolymers can be produced, and olefinic polymers can be produced which have a high melting point (Tm) even if the comonomer content is increased when producing the olefinic polymer.