Abstract:
A porous polymer blend, and a method of producing a porous polymer blend from at least two immiscible polymers. The at least two immiscible polymer being blended together and exhibiting the absence of complete phase separation. The method of producing a porous polymer blend comprising: forming a liquid composition comprising at least two immiscible polymers dissolved in a common solvent; subjecting the liquid composition to a reduction in temperature to cause at least two immiscible polymers to phase separate into a common polymer rich phase and a common polymer poor phase; solidifying the at least two immiscible polymers in the common polymer rich phase so as to avoid complete phase separation of the at least two immiscible polymers; and removing the common polymer pore phase to provide a blend of the at least two immiscible polymers having a porous morphology.
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:
Multi-layer, microporous polyolefin sheet materials are provided. The sheet materials comprise at least two microporous polyolefin layers, the layers being autogenously bonded and having substantially the same porosity as prior to bonding.
Abstract:
A pseudo-gel comprising a suitable solvent in an amount of 99 to 90 percent by weight and an ultra-high-molecular-weight polyethylene in an amount of 1 to 10 percent by weight, said polyethylene being a semicrystalline network with adjustable crystalline morphology comprising randomly dispersed and oriented chain-folded single crystals, stacks of single crystals, spherulite crystals, and extended-chain shish-kebab-type of fibrils with lengths up to a few millimeters and widths up to 20 .mu.m. Also, the semicrystalline ultra-high molecular-weight polyethylene obtained by removal of said solvent from the pseudo-gel. Further, a method for making the pseudo-gel and the ultra-high-molecular-weight polyethylene product.
Abstract:
There is disclosed a substantially skinless microporous polypropylene membrane characterized by having(a) a bubble point of about 25 to about 50 psi;(b) a thickness of about 3 to about 7 mils;(c) a nitrogen flow rate of at least 0.5 liters per square centimeter-minute;(d) a burst strength of at least 10 psi; and(e) an S value of about 15, or less.There is also disclosed a method of preparing a microporous polypropylene membrane comprising heating a mixture of about 30 percent polypropylene and about 70 percent, N,N-bis(2-hydroxyethyl)tallowamine, by weight, to a temperature and for a time sufficient to form a homogeneous solution, casting or extruding said solution at a thickness of about 3 to about 7 mils, onto a chill roll maintained at a temperature of from about 50.degree. to about 80.degree. C., allowing said solution to solidify on said chill roll to form a solid sheet, removing said solid sheet from said chill roll and removing at least a substantial portion of the liquid from said sheet to form the microporous polypropylene membrane.
Abstract:
Novel microporous polymers in forms ranging from films to blocks and intricate shapes from synthetic thermoplastic polymers, such as, olefinic, condensation, and oxidation polymers, are disclosed. In one embodiment the microporous polymers are characterized by a relatively homogeneous, three-dimensional cellular structure having cells connected by pores of smaller dimension. Also disclosed is a process for making microporous polymers from such thermoplastic polymers by heating a mixture of the polymer and a compatible liquid to form a homogeneous solution, cooling said solution under non-equilibrium thermodynamic conditions to initiate liquid-liquid phase separation, and continuing said cooling until the mixture achieves substantial handling strength. Also disclosed are microporous polymer products which contain relatively large amounts of functionally useful liquids and behave as solids.
Abstract:
A PROCESS FOR THE MANUFACTURE OF A POROUS SHEET MATERIAL WHICH COMPRISES THE STEPS OF APPLYING A LIQUID HOMOGENEOUS MIXTURE OF A POLYMER, E.G., A POLYURETHANE, AND AN AUXILIARY SUBSTANCE, E.G., CAPROLACTAM, TO A SUBSTRATE, COOLING THE MIXTURE TO A TEMPERATURE AT WHICH THERE IS FORMED A SOLID PHASE SUBSTANTIALLY COMPRISING THE POLYMER, THE AUXILIARY SUBSTANCE COMPRISING A SOLVENT FOR THE POLYMER WHICH UPON COOLING OF THE MIXTURE PRECIPITATES FROM THE MIXTURE INTO A SEPARATE SOLID PHASE BEFORE THE FORMATION OF THE SOLID POLYMER PHASE IS COMPLETED, AND THEREAFTER REMOVING THE AUXILIARY SUBSTANCE TO FORM A HOMOGENEOUS UNIFORM POROUS SHEET MATERIAL.
Abstract:
The composition, advantageously an emulsion or a foam, includes an internal phase dispersed in a hydrophilic continuous phase, the percentage of the internal phase being higher than 50%. The emulsion composition contains nanocrystals of a polysaccharide other than cellulose, advantageously chitin, that are located at the interface between the internal phase and the hydrophilic continuous phase.
Abstract:
The present invention relates to a method for producing a resin composition foam comprising dissolving a supercritical fluid in a resin composition containing polytetrafluoroethylene and another resin other than polytetrafluoroethylene at a temperature equal to or higher than a glass transition point of the other resin, then foaming the resin composition by removing the supercritical fluid at a temperature lower than a temperature obtained by adding 15° C. to a thermal deformation starting temperature of the other resin, and subsequently cooling. In addition, the present invention relates to a resin composition foam, wherein the resin composition foam has a pore size of less than 50 μm, and the resin composition foam is any one of an open cell, a closed cell and a monolith type.
Abstract:
A process for producing a porous body with different physical properties in desired regions is provided by pore forming treatment, not by bonding two or more materials made porous beforehand, with, for example, an adhesive. Raw materials are prepared, each of which contains a polymer and a raw material preparation solvent. At least two types of the raw materials having different compositions are prepared. Thereafter, the respective raw materials are frozen into desired shapes to form frozen bodies thereof. The frozen bodies thus formed are brought into contact with each other to form an assembly thereof, the assembly is exposed to a condition under which the frozen bodies begin to melt, and the assembly is then freeze-dried. Thus, a porous body having regions different in physical properties can be obtained. Such a porous body can be used as, for example, an adhesion inhibitory material or a scaffold for a cell culture.