Korea Institute of Science and Technology

Korea Advanced Institute of Science and Technology

Hanil Synthetic Fiber Co., Ltd.

Wha Seop Lee

Seong M Jo

Chong S Park

Suk Won Chun

Hyung Sun Kim

Byung Won Cho

Kun You Park

Won Il Cho

Tae W Son

Ho Joong Kang

Chul J Lee

Byung G Min

Kyung Suk Yun

Dong Beom Kim

Seong Joo Lee

Un Seok Kim

Byoung Chul Kim

Young Geun Park

Young Se Oh

Seok Gu Go

Seok Ku Ko

Seung Lak Lee

Seok Gu Ko

Sung Won Choi

Han-Sik Yoon

Yong K Hong

Dong Bok Kim

Hans S Yoon

Jong Su Park

The present invention provides a lithium secondary battery and its fabrication method. More particularly, the present invention provides a lithium secondary battery comprising a super fine fibrous porous polymer separator film and its fabrication method, wherein the porous polymer separator film is fabricated by the following process: a) melting at least one polymer or dissolving at least one polymer with organic solvents to obtain at least one polymeric melt or at least one polymeric solution; b) adding the obtained polymeric melt or polymeric solution to barrels of an electrospinning machine; and c) discharging the polymeric melt or polymeric solution onto a substrate using a nozzle to form a porous separator film. The lithium secondary battery of the present invention has the advantages of better adhesion with electrodes, good mechanical strength, better performance at low and high temperatures, better compatibility with organic electrolyte solution of a lithium secondary battery.

Lithium secondary battery comprising a super fine fibrous polymer separator film and its fabrication method

Disclosed is a process for preparing a homogeneous cellulose solution which is capable of, forming a mixture where a cellulose pulp powder is mixed and swollen with a liquid NMMO hydrate solvent supercooled under a melting point and subjecting the mixture to a dissolution treatment, thereby producing a homogeneous cellulose solution having a substantially low decomposition characteristic. The process produces a cellulose pulp mixing powder that is first swollen in a liquid NMMO solvent supercooled under a melting point by minimizing the dissolution of cellulose by the liquid NMMO solvent and maximizing the swelling thereof by the liquid NMMO solvent, thereby resulting in a maximum homogeneity of the solution and maintains the minimized decomposition states of the cellulose and the NMMO solvent, thereby resulting in the improvement of productivity and the simplicity of the process.

Process for preparing homogeneous cellulose solution by using supercooled liquid N-methylmorpholine-N-oxide hydrate solvent

The present invention relates to an apparatus of polymer web by electrospinning process and manufacturing method thereof, which can manufacture porous polymer web using an electrospinning method. The method for manufacturing porous polymer web by electrospinning process includes the steps of: forming, pressurizing and supplying at least one or more kinds of polymer materials in a liquid state; and discharging and piling the polymer materials to a collector through one or more charged nozzles, the collector being located under the nozzles and charged to have a polarity opposed to the polarity of the charged nozzles, the collector moving in a prescribed speed.

Apparatus of polymer web by electrospinning process

Process for preparing a homogeneous cellulose solution using

There is disclosed a method for purifying a used aqueous N-methylmorpholine N-oxide solution reclaimed from a spinning aqueous solution, which results from a coagulation solution into which a cellulose dope containing N-methylmorpholine N-oxide is extruded through a spinning die and from a washing solution for the coagulated cellulosic articles in manufacture processes for cellulose fibers or films, comprising adding an oxidant to the used aqueous N-methylmorpholine N-oxide solution to remove impurities therefrom through oxidation N-methylmorpholine into N-methylmorpholine N-oxide and break down of the chromophores of the impurities. Utterly distinguished from, conventional methods in the principle, the method is very simple and efficient as well as far superior to the conventional methods using ion exchange resin in the decoloration. In addition, it needs not suffer a loss of amine oxide as usual in the ion exchange resin. Further, the oxidant can achieve the decolorization without influence of concentration of amine oxides. The amine oxide decolorized by the oxidant may be used to prepare the cellulose dope without any more purification. Provided that sequential use of the oxidant and the resin or active carbon, there are brought about much higher efficiency as well as much purer aqueous amine oxide solution.

Method for the purification of reclaimed aqueous N-methylmorpholine

This specification discloses pelletized pre-dope granules of cellulose and a tertiary amine oxide wherein the tertiary amine oxide is homogeneously dispersed throughout the cellulose and a process for making them. According to the invention, the pelletized pre-dope granules can be prepared by a process comprising of the steps of feeding cellulose to a mill with knife-edged blades, together with the tertiary amine oxide powder having a water content of 5 to 17% by weight; and milling and blending the resulting solid mixture in the blender, while heating the solid mixture at a temperature sufficient to agglomerate as a result of instantaneous melting of tertiary amine oxide powder and simultaneous penetration of the molten amine oxide into cellulose without dissolving the cellulose. The pre-dope granules thus obtained can be used in making shaped cellulosic articles such as fibers and films. According to the invention, the shaped cellulosic articles can be produced from the process comprising the steps of heating the pre-dope granules in the barrel of an extruder to give a dope solution, extruding the resulting dope solution to provide an extrudate to be spun, and spinning the extrudate through a spinnerette or die.

Pelletized pre-dope granules of cellulose and tertiary amine oxide,

New wholly aromatic polyamides are provided. This polymers are prepared by a mixture of N,N'-bis(4-aminophenyl)-isophthalamide and p-phenylenediamine in a tertiary amide solvent containing an alkali metal salt such as LiCl and a tertiary amine as an acid acceptor. The polymers are easily dry-jet spun to form a fiber and cast to form a film. The fiber and film so obtained have ultrahigh tenacity, elasticity and elongation.

Wholly aromatic polyamide from N,N'-bis (4-amino phenyl)-isophthalamide

High molecular weight block copolyamides useful in the production of fibers of high strength and modulus, having the following formula: ##STR1## wherein X is --CH.sub.2 --.sub.m, wherein m is 0 to 12, ##STR2## wherein Z is C(CH.sub.3).sub.2, zero, oxygen or SO.sub.2, are prepared from N,N'-bis(4-aminophenyl) terephthalamide having the formula: ##STR3## which is itself prepared by condensing aniline with dimethyl terephthalate or terephthalic acid, nitrating the product produced thereby and finally hydrogenating the resultant compound.

Wholly aromatic or aliphatic aromatic block copolyamides and process

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Seoul, South Korea

Wha Seop Lee