Abstract:
The present systems and methods utilize a polyamic acid solution as a precursor to form a polyimide bead having desired properties. The polyamic acid solution may be formed into a polyamic acid droplet. The polyamic acid droplet is then processed to form a polyamic acid bead, such as by extraction of solvent to concentrate the polyamic acid or by partial chemical imidization of the polyamic acid. The polyamic acid bead is then better able to retain its shape during subsequent processing steps, such as drying and pressurizing, before final thermal imidization.
Abstract:
The present invention relates to a multi-layered microporous polyolefin film for a battery separator and a method for preparing the same. The microporous multi-layered film of the present invention has a characteristics to have both the low shutdown temperature conferred by the polyethylene and the high melt fracture temperature conferred by the polypropylene and heat-resistant filler. In addition, it has the high strength and stability conferred by the micropores prepared under wet process and the high permeability and high strength conferred by the macropores prepared under dry process. Therefore, this multi-layered film can be used effectively to manufacture a secondary battery with high capacity and high power.
Abstract:
Porous spherical particles of polyamide 11 or polyamide 12 can be produced by an industrially advantageous process which comprises the steps of mixing a polyamide solution of polyamide 11 or polyamide 12 dissolved in a phenol compound and a low molecular weight aliphatic alcohol which is a poor solvent for the polyamides but is well compatible with the phenol compound in the presence of a high molecular weight alkylene glycol to prepare a mixture solution having an initial viscosity of 10 mPa·s or more, and allowing the mixture solution to stand, to precipitate polyamide particles.
Abstract:
A method for preparation of porous polyimide microparticles comprising, forming polyamide acid microparticles by pouring polymer solution prepared by dissolving polyamide acid containing 0.5 to 80 weight % of alkali metal salt to polyamide acid by 0.1 to 15 weight % concentration into a poor solvent selected from the group consisting of aliphatic solvents, alicyclic solvents, aromatic solvents, CS2 and mixture of two or more these solvents and the temperature of which is adjusted to the range from −20° C. to 60° C., wherein particle size of said polyamide acid microparticles is adjusted to 50 nm to 10000 nm by controlling the temperature of said poor solvent, pore size of said polyamide acid microparticles is adjusted to the range from 20 nm to 500 nm and porosity of said polyamide acid microparticles is adjusted to the range from 0.1% to 30% by controlling a content or a kind of said alkali metal salt, then treating said polyamide acid microparticles by chemical imidation or thermal imidation, or by thermal imidation after chemical imidation so that the particle size distribution, pore size and porosity of said polyamide acid microparticles can be maintained.
Abstract:
The present invention relates to a porous gelatin material in the form of spherical particles with a continuous pore structure and cast, three-dimensional, porous gelatin structures. The invention also comprises methods for preparation of the porous gelatin materials and structures. The method for preparing the porous gelatin material in the form of spheres with a continuous pore structure comprises the steps of preparing a homogenous water-based gelatin solution, adding an emulsifier with an HLD value >9, adding a first composition comprising an organic solvent and an emulsifier with an HLB value >9, adding a second composition comprising an organic solvent and an emulsifier with an HLB value
Abstract:
A .gamma.-ray-sterilizable hydrophilic porous material has been found which includes a continuous layer made of a synthetic polymer compound forming a porous substrate and a hydrophilic and .gamma.-ray-resistant polymer supported on at least part of the surface of the porous substrate in an amount not less than 5% by weight, based on the porous substrate. The hydrophilic porous material has an average pore diameter in the range of 0.02 to 20 .mu.m, a porosity in the range of 10 to 90% and a wall thickness in the range of 10 .mu.m to 5.0 mm.
Abstract:
An active agent delivery device comprises (a) microporous material comprising a matrix consisting essentially of linear ultrahigh molecular weight polyolefin, a large proportion of finely divided water-insoluble filler of which at least about 50 percent by weight is siliceous, and interconnecting pores; and (b) a releasable active agent or precursor thereof associated with at least a portion of the filler.
Abstract:
A flat permeable membrane of polyolefin 10 to 500 .mu.m in thickness, which membrane has compact layers of intimately bound fine particles of polyolefin formed one each in the opposite surface regions of the membrane and a layer of an aggregate of fine discrete particles of an average diameter of 0.01 to 5 .mu.m formed between the compact layers and, consequently, has fine through pores labyrinthically extended in the direction of thickness of the membrane to establish communication between the opposite surfaces of the membrane and a method for the manufacture of the permeable membrane.
Abstract:
An artificial flower comprises at least one petal of microporous material which comprises a matrix consisting essentially of linear ultrahigh molecular weight polyolefin, a large proportion of finely divided water-insoluble siliceous filler, and interconnecting pores, and which microporous material has regions of stretch-induced molecularly oriented polymer in the matrix.
Abstract:
A porous membrane for use in the separation of blood components, made of a polyolefin, having a wall thickness in the range of 10 to 500 .mu.m, and possessing through holes having an average diameter of 0.01 to 5 .mu.m at a porosity in the range of 10 to 85%, which porous membrane is characterized by exhibiting a shrinkage of not more than 6.0% in a heat treatment carried out at 121.degree. C. for 120 minutes. A method for the manufacture of the porous membrane is also disclosed.