Halogen-free, microporous polyolefin membranes are disclosed herein. The halogen-free, microporous polyolefin membranes can be manufactured using an environmentally friendly manufacturing process that includes extrusion of polymer-plasticizer mixtures followed by sheet formation and extraction of the plasticizer with a halogen-free solvent. The halogen-free solvent has a flashpoint greater than about 23? C. and an initial boiling point at least about 50? C. lower than the flashpoint of the plasticizer. The process can further be a closed loop process in which the halogen-free solvent can be reused.

An asymmetric hollow fiber (CMS) carbon molecular sieve is made by providing a dope solution comprised of a polvimide and a solvent, at a temperature greater than 250 C. that is less than the storage modulus at a temperature of 250 C., but no more than ten times less as measured using dynamic mechanical thermal analysis from 250 C. to a temperature where the polyimide carbonizes. The polvimide is shaped into a hollow polvimide fiber, the solvent removed and the polyimide hollow fiber is heated to pyroiyze the polvimide and form the asymmetric hollow carbon molecular sieve. The asymmetric hollow fiber carbon molecular sieve has a wall that is defined by an inner surface and outer surface of said fiber and the wall has an inner porous support region extending from the inner surface to an outer raicroporous separation region that extends from the inner porous support region to the outer surface. Surprisingly, when the polyimide has the particular storage modulus characteristics, the method allows for the hollow fiber CMS to be made without any pre-treatmenis or additives to inhibit stractural collapse of the inner microporous region.

Methods are provided for producing a biaxially oriented nanoporous UHMWPE membrane. The method can include combining a petroleum jelly, an ultra-high-molecular-weight polyethylene (UHMWPE), and an antioxidant, forming a suspension, feeding the suspension into an extruder to produce a gel filament, pressing the gel filament to form a gel film, subjecting the gel film to an annealing temperature, and extracting the petroleum jelly from the gel film.

There is presented a battery comprising at least one densified expanded polymer membrane covering an opening of a housing. The at least one densified expanded polymer membrane may have a crystallinity of 75% to 100%. In some embodiments, the at least one densified expanded polymer membrane has a CO.sub.2 permeability to water vapour permeability ratio of more than 0.5.

A separation membrane has high strength and low leakage property while maintaining high gas permeability using poly(4-methyl-1-pentene) excellent in chemical resistance and gas permeability. The separation membrane contains poly(4-methyl-1-pentene) as a main component, in which a ratio RA of a rigid amorphous of poly(4-methyl-1-pentene) in the separation membrane is 43% or more and 60% or less, a porosity is 30% or more and 70% or less, and a dense layer is provided on at least one surface.

Novel carbon molecular sieve (CMS) compositions comprising carbonized vinylidene chloride copolymer having micropores with an average micropore size ranging from 3.0 to 5.0. These materials offer capability in separations of gas mixtures including, for example, propane/propylene; nitrogen/methane; and ethane/ethylene. Such may be prepared by a process wherein vinylidene chloride copolymer beads, melt extruded film or fiber are pretreated to form a precursor that is finally carbonized at high temperature. Preselection or knowledge of precursor crystallinity and attained maximum pyrolysis temperature enables preselection or knowledge of a average micropore size, according to the equation ?=6.09+(0.0275?C)?(0.00233?T), wherein ? is the average micropore size in Angstroms, C is the crystallinity percentage and T is the attained maximum pyrolysis temperature in degrees Celsius, provided that crystallinity percentage ranges from 25 to 75 and temperature in degrees Celsius ranges from 800 to 1700. The beads, fibers or film may be ground, post-pyrolysis, and combined with a non-coating binder to form extruded pellets, or alternatively the fibers may be woven, either before or after pre-treatment, to form a woven fiber sheet which is thereafter pyrolyzed to form a woven fiber adsorbent.

Metal organic framework membranes can be used in gas separation applications.

Metal organic framework membranes can be used in gas separation applications.

The present invention relates to a method of preparing a perm-selective porous membrane and a method of separating gases using the prepared porous membrane. According to the present invention, a membrane is synthesized using a hierarchically structured alumina porous support by a counter diffusion method. During this synthesis, the diffusion rate of metal ions loaded on the porous support is controlled by controlling the pore size of the porous support, and the position at which the membrane is synthesized is controlled by synthesizing the membrane inside the support. This can increase the physical stability of the membrane and make the membrane thicker so as to ensure higher H.sub.2/CO.sub.2 separation factors.

The present disclosure provides methods of controlling the size of cellulose crystals by mixing a first composition comprising cellulose and coagulating this mixture with varying concentrations of hydrogen peroxide.