Abstract: A process for improving the permselectivity of asymmetric polyaramide gas separation membranes is disclosed. The process involves contacting the membrane with a dilute solution of a surfactant in a solvent which preferably swells the membrane material. The surfactants are anionic, nonionic or amphoteric with the fluorinated nonionic surfactants being preferred.

Abstract: A permselective polyimide membrane having phenylindane residues incorporated into the polyimide backbone chain exhibiting high selectivity while maintaining good gas permeation rates and a process for using.

Abstract: A process of producing a polyimide gas separation membranes comprising adding an oligomeric or polymeric aromatic epoxy resin to the dope solution, the resin being soluble in the polyimide or polyamic acid precursor, the solvent and the final membrane and the membrane comprising a blend of the polyimide and the resin.

Abstract: Process of reacting polyimide membranes for separation of mixtures of fluids and particularly separation of mixtures of gas with primary or secondary mono-, di-, tri- or polyamines and the resultant products are disclosed. This modification results in improved gas permeation properties and, in some cases, improved environmental resistance.

Abstract: Incorporation into polyacetal molding compositions stabilized with a non-meltable polymer stabilizer of 0.02-1.0 weight percent of at least one amide-containing phenolic antioxidant results in significantly improved long term stability, as evidenced by greater retention of physical properties over time, of such compositions.

Abstract: A process for producing integrally-skinned asymmetric poly(phenylene oxide) gas separation membranes is disclosed. The process involves forming a solution of the poly(phenylene oxide) in an aprotic solvent at an elevated temperature, forming a nascent membrane from the solution, partially drying the nascent membrane, followed by coagulating the partially dried nascent membrane in a coagulation bath formed from a non-solvent for the poly(phenylene oxide) which non-solvent is miscible with the aprotic solvent.

Abstract: Aromatic polyimides of the formula: ##STR1## where --Ar-- is ##STR2## --Ar'-- is ##STR3## --Ar"-- is ##STR4## where --Z, and --Z.sub.1, independently are --Cl, --Br or --I; where --X, --X.sub.1, --X.sub.2 and --X.sub.3 independently are --CH.sub.3 or --C.sub.2 H.sub.5 ; and --Y,--Y.sub.1,--Y.sub.2 and --Y.sub.3 are primary or secondary alkyl groups having 3 to 12 carbon atoms, provided that when m is greater than 0, r is 0 and that when L is greater than 0, r and s are 0, are disclosed. These polyimides are very soluble, even in weak solvents such as toluene.

Abstract: An aromatic copolyimide gas separation membrane and the process of using it to separate one or more gases from a mixture of gases are disclosed. The aromatic copolyimide is the condensation product of a aromatic tetracarboxylic dianhydride with a phenylene diamine and a methylene dianiline both of which diamines are substituted with alkyl groups on all positions ortho to the amino groups.

Abstract: Semiflexible aromatic polyimides for preparing gas separation membranes and the process of using to separate at least one gas from a mixture of gases is disclosed. The aromatic polyimides are prepared by polycondensation of aromatic tetracarboxylic dianhydrides with 20 to 80 mol percent of a methylene dianiline which is alkyl substituted on all positions ortho to the amine functions. The remaining diamine constituent is not so substituted.

Abstract: Highly-soluble, fully-cyclized siloxane polyimides, which contain at least in part, polymerized units derived from 4,4'-[2,2,2-trifluoro-1-(trifluoromethyl) ethylidene]-bis(1,2-benzenedicarboxylic acid anhydride), (6FDA), are disclosed. The polymeric compositions, their preparation and film/coating products are described.

Abstract: Highly soluble, optically transparent to clear aromatic polyimides in the visible range are disclosed. The dianhydrides from which the polyimides are prepared are 4,4'-[2,2,2-trifluoro-1-(trifluoromethyl) ethylidene] bis(1,2-benzenedicarboxylic anhydride) which can be partially replaced with either pyromellitic dianhydride or 3,3',4,4'-benzophenone tetracarboxylic dianhydride. The diamines from which the polyimides are prepared are m- or p- phenylene diamines which are substituted ortho to the amino groups with primary or secondary alkyl groups having 1 to 6 carbon atoms preferably methyl or ethyl.

Abstract: Aromatic polyimide gas separation membranes containing the repeating unit: ##STR1## where --Ar-- =is ##STR2## or mixtures thereof, ##STR3## or mixtures thereof Where --X, X.sub.1, X.sub.2, and X.sub.3 are independently primary or secondary alkyl groups having 1 to 6 carbon atoms preferably methyl or ethyl, --Z is --H, --X, --X.sub.1, --X.sub.2, or --X.sub.

Abstract: A process for applying and polymerizing a monomeric material to a gas separation membrane to improve the permselectivity of the membrane with respect to at least one pair of gases is disclosed.

Abstract: Highly soluble, optically transparent aromatic polyimides of the following formula are disclosed: ##STR1## where --X and --X.sub.1 are independently primary or secondary alkyl groups having 1 to 6 carbon atoms,--X is different than --X.sub.1,--Y is independently --H, or --Z,--Z is independently --Cl, --Br or --I,r=0-100% of r+t, ands=100%t=100% -r of r+t are disclosed.

Abstract: Aromatic polyimide gas separation membranes of the formula: ##STR1## or mixtures thereof, --R'--is ##STR2## linear alkylene groups of the formula (CH.sub.2).sub.1-3 or mixtures thereof, where --R" is ##STR3## are independently primary or secondary alkyl groups having 1 to 6 carbon atoms preferably methyl, ethyl, or isopropyl --Z and --Z.sub.1 are independently hydrogen or halogens such as iodine, bromine or chlorine preferably chlorine, and where n=0-4.

Abstract: Semi-flexible aromatic polyimides, prepared by polycondensation of dianhydrides with diamines having alkyl substituents on all ortho positions to the amine functions, or with mixtures of diamines, some components having substituents on all positions ortho to the amine functions, are disclosed. Membranes formed from this class of polyimides have improved environmental stability and superior gas permeability. The range of gas permeation properties observed allows for the tailoring of membrane material for widely diverse gas separations. The high permeabilities of some gases from multicomponent mixtures is due to the optimization of the molecular free volume in the polymer.

Abstract: Semi-flexible aromatic polyimides, prepared by polycondensation of dianhydrides with phenylene diamines having alkyl substituents on all ortho positions to the amine functions incorporating at least in part 3,3',4,4'-benzophenone tetracarboxylic dianhydride, are auto photochemically crosslinkable. Membranes formed from this class of crosslinked polyimides have improved environmental stability and superior gas selectivity than the corresponding uncrosslinked polyimide. The range of gas permeation properties observed allows for the tailoring of membrane material for widely diverse gas separations. The high permeabilities of some gases from multicomponent mixtures is due to the optimization of the molecular free volume in the polymer.

Abstract: A highly permeable aromatic polyimide gas separation membrane and the process of using it are disclosed. The aromatic polyimide has the formula ##STR1## wherein --Ar-- is ##STR2## or mixtures thereof, --X, --X.sub.1, --X.sub.2 and --X.sub.3 independently are alkyl groups having 1 to 6 carbon atoms or aromatic groups having 6 to 13 carbon atoms, and --Z is --H, --X, --X.sub.1, --X.sub.2, or --X.sub.3 ; and R is ##STR3## or mixtures thereof.

Abstract: Described herein is a method for bonding a skin member such as metal, plastic, perforated acoustic skin, or fiberglass or graphite reinforced plastic, to a honeycomb core support structure such as lightweight hollow hexagonally shaped tubes. Such a method can be used in the construction industry for making panels and walls and similar structures, and in the aerospace industry for making airplane and satellite structures, etc. The adhesive employed is an adhesive-coated fabric material which is partially cured onto the honeycomb and cooled down, following which most of the adhesive material is removed when the coated fabric is peeled away. This leaves an optimum amount of adhesive in the most effective locations on the wall edges of the honeycomb cells where it is needed for bonding the core to the skin. The skin member is then bonded to the honeycomb by bringing the adhesive to its final cure.

Abstract: A conveyor system in which free flowing granules or particles are conveyed through a flexible tube having a helical channel defined on the internal surface of the tube by rotating the tube about its longitudinal axis.