Abstract:
The invention relates to a method for removing a process solvent (P-sol) from a polymer extrudate, especially in connection with a process for producing a microporous membrane. The method involves contacting the extrudate with chlorinated hydrocarbon (CHC) and hydrofluoroether (HFE) in a first stage; contacting the extrudate from the first stage with HFE in a second stage; combining the first and second waste streams and then separating the P-sol from the combined streams to make an HFE-CHC stream; cooling the HFE-CHC stream to make an HFE-rich phase and a CHC-rich phase; and conducting the CHC-rich phase and/or the HFE-rich phase to step (A).
Abstract:
Provided is a microporous material, e.g., a microporous sheet material, having a matrix of polyolefin, finely-divided, substantially water insoluble particulate filler, a network of interconnecting pores communicating throughout the microporous material, and at least one retrospectively identifiable taggant material embedded within the matrix, wherein the polyolefin is present in the microporous material in an amount of 20 to 60 weight percent, based on the weight of the microporous material. The taggant material provides a marker, signature or code that is capable of retrospective identification by machine, instrument or by the naked eye. Articles including the microporous material and processes for preparing the microporous material also are provided.
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 HLB 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:
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:
Monolithic organic copolymer prepared by copolymerisation of an alkylstyrene and a divinylbenzene or a derivative thereof in the presence of a porogen, wherein said porogen comprises decanol and at least one of the group consisting of tetrahydrofuran and toluene.
Abstract:
Porous membranes having a micro phase separation structure and showing a light transmittance at the wavelength of 400 nm of not less than 30% are obtained by the dry phase conversion method comprising drying a coating layer of a dope containing a polymer, a good solvent for the polymer and a poor solvent for the polymer which solvent has a higher boiling point than the good solvent. The polymer includes cellulose derivatives, vinyl-series polymers such as acrylonitrile-series polymers and (meth)acrylic acid ester-series polymers, polysulfone-series polymers, and the like. The porous polymer membranes have a porosity of 10 to 60%, a mean pore size of about 0.002 to 0.35 &mgr;m and a maximum pore size of not greater than 0.4 &mgr;m. These porous membranes shows not only excellent transparency but also high productivity.
Abstract:
The present invention provides a microporous material or a membrane in which the membrane includes an azlactone moiety which is blended with or grafted to a thermoplastic polymer to provide a porous material having an internal structure characterized by a multiplicity of spaced, randomly disposed, non-uniform shaped, equiaxed particles of the polyazlactone polymer/thermoplastic polymer blends or the azlactone-graft copolymer. Each of the adjacent particles throughout the material are separated from one another to provide said material with a network of interconnected micropores and each of the particles are connected to each other by a plurality of fibrils. In addition to unmodified azlactone membranes, membranes which have been modified by subsequent reaction of the azlactone moiety with a suitable nucleophile are also included within the scope of the present invention. Preferred nucleophiles capable of reacting with an azlactone membrane of this invention include biologically significant nucleophiles such as amines, thiols and alcohols as well as amino acids, nucleic acids and proteins.
Abstract:
This invention relates to highly porous, crosslinked bodies derived from nitrogen-containing polymers, and a process of producing the porous bodies which comprises dissolving a nitrogen-containing polymer to form a gel, ionically crosslinking the gel, and covalently further crosslinking the ionically crosslinked gel body.
Abstract:
The invention concerns porous fibers and membranes, methods for their preparation and for their use. The fibers are characterized by a smooth porous surface and an apparent density of between about 10 to 90% of the true density of the polymeric starting material employed. The process involves the formation of a homogeneous mixture of at least two components, one of which is a meltable polymer and another liquid inert with respect to the polymer. The mixture formed must be of a binary type, in which there is a temperature range of complete miscibility and a range in which there is a miscibility gap. The mixture is extruded at a temperature above the separation temperature into a bath containing at least some of the inert liquid which is at a temperature below the separation temperature. Upon introduction of the mixture into the bath, the fiber structure of the product is fixed.
Abstract:
A micro-porous membrane of ultra-high-molecular-weight alpha-olefin polymer having a weight-average molecular weight greater than 5.times.10.sup.5, the micro-porous membrane having through holes 0.01 to 1 micrometer in average pore size, with a void ratio from 30 to 90% and being oriented such that the linear draw ratio in one axis is greater than two and the areal draw ratio is greater than ten. The micro-porous membrane is obtained by forming a gel-like object from a solution of an alpha-olefin polymer having a weight-average molecular weight greater than 5.times.10.sup.5, removing at least 10 wt % of the solvent contained in the gel-like object so that the gel-like object contains 10 to 90 wt % of alpa-olefin polymer, orientating the gel-like object at a temperature lower than that which is 10.degree. C. above the melting point of the alpa-olefin polymer, and removing the residual solvent from the orientated product. A film is produced from the orientated product by pressing the orientated product at a temperature lower than that of the melting point of the alpha-olefin polymer.