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Membrane Technology and Applications

Correlation of separation factor versus permeability for polymeric membranes

Elastic substantially linear olefin polymers are disclosed which have processability similar to highly branched low density polyethylene (LDPE), but the strength and toughness of linear low density polyethylene (LLDPE). The polymers have processing indices (PI's) less than or equal to 70 percent of those of a comparative linear olefin polymer and a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a traditional linear olefin polymer at about the same I2 and Mw?Mn. The novel polymers can also have from 0.01 to 3 long chain branches/1000 carbons along the polymer backbone and have higher low/zero shear viscosity and lower high shear viscosity than comparative linear olefin polymers. The novel polymers can also be characterized as having a melt flow ratio, I10/I2, » 5.63, a molecular weight distribution, Mw/Mn, defined by the equation: Mw/Mn « (I10/I2) - 4.63, and a critical shear stress at onset of gross melt fracture greater than 4 x 10?6? dyne/cm2.

Elastic substantially linear olefin polymers

Amphiphilic poly(phenylquinoline)-block-polystyrene rod-coil diblock copolymers were observed to self-organize into robust, micrometer-scale, spherical, vesicular, cylindrical, and lamellar aggregates from solution. These diverse aggregate morphologies were seen at each composition, but their size scale decreased with a decreasing fraction of the rigid-rod block. Compared to coil-coil block copolymer micelles, the present aggregates are larger by about two orders of magnitude and have aggregation numbers of over 10(8). The spherical and cylindrical aggregates have large hollow cavities. Only spherical aggregates with aggregation numbers in excess of 10(9) were formed in the presence of fullerenes (C60, C70) in solution, resulting in the solubilization and encapsulation of over 10(10) fullerene molecules per aggregate.

https://science.sciencemag.org/content/sci/279/5358/1903.full.pdf

Self-Assembled Aggregates of Rod-Coil Block Copolymers and Their Solubilization and Encapsulation of Fullerenes

Tailoring mixed matrix composite membranes for gas separations

Block Copolymers: Overview and Critical Survey

Ethylene copolymers having a density of about 0.91 to 0.94 and a melt flow ratio of about ≧26 to ≦40 are readily produced in a low pressure gas phase process at a productivity of ≧500,000 pounds of polymer per pound of Ti with a catalyst formed from selected organo aluminum compounds and a composition prepared by copulverizing magnesium dihalide with a complex obtained by contacting a titanium compound of the structure Ti(OR) a X b with an ether, ester, ketone or amine, wherein R is a C 1 to C 14 aliphatic or aromatic hydrocarbon radical, or COR' where R' is a C 1 to C 14 aliphatic or aromatic hydrocarbon radical, X is Cl, Br, I or mixtures thereof, a is 0 or 1, b is 2 to 4 inclusive and a+b=3 or 4.

Preparation of low-density ethylene copolymers in fluid bed reactor

Solid polyolefin catalysts are adapted for use in low pressure gas phase fluid bed polymerization processes by being mixed with selected particulate organic support materials in a high speed bladed finishing device so as to cause the catalysts materials to become embedded in, and/or adhered to, softened particles of the support material.

Olefin polymerization catalysts adapted for gas phase processes

Stereoregular polymers having a molecular weight distribution of less than 5.0 and an isotactic index in excess of 96 percent are produced by polymerizing an alpha-olefin having 3 to 8 carbon atoms in a low pressure gas phase fluid bed process at a temperature in excess of 80° C. employing a heat stable catalyst system comprising (a) a solid catalyst component containing magnesium, titanium, halide and a polycarboxylic acid ester containing two coplanar ester groups attached to adjacent carbon atoms, as inside electron donor, (b) an organoaluminum cocatalyst, and (c) a silicon compound containing a silicon-oxygen-carbon linkage, as outside electron donor.

Process for producing stereoregular polymers having a narrow molecular weight distribution

A series of polysulfone/poly(dimethylsiloxane) (AB)n block copolymers have been synthesized over a wide composition range by varying the molecular weights of the polysulfone and poly(dimethylsiloxane) blocks. The properties vary from a rigid material at high polysulfone content (>65% polysulfone) to an elastomeric material at high poly(dimethylsiloxane) content (>65% poly(dimethylsiloxane)).



A simple extension of MAXWELL's analysis of heterogeneous systems is shown to be applicable to the prediction of permeability data and a similar treatment of KERNER's analysis can be used for predicting modulus data. Analysis of both the permeability data and modulus data predict a similar phase inversion composition for this two-phase block copolymer.



Different properties can be obtained with a given block copolymer composition by casting films from different solvents or by swelling the films in a non-solvent which preferentially swells one phase only. The tendency of poly(dimethylsiloxane) to crystallize at low temperature is dependent upon the flexibility of the block copolymer, which can be influenced by the method of film preparation.



Eine Reihe von Polysulfon-Polydimethylsiloxan-(AB)n-Blockcopolymeren wurde uber eine breite Zusammensetzungsweite durch Variation des Molekulargewichtes der Polysulfon- und Polydimethylsiloxan-Blocke dargestellt. Die Eigenschaften dieser Polymeren reichen von einem harten Stoff bei hohem Polysulfongehalt (>65% Polysulfon) bis zu einem elastischen Stoff bei hohem Gehalt an Polydimethylsiloxan (>65% Polydimethylsiloxan).



Es wird gezeigt, das eine einfache Erweiterung der MAXWELL-Analyse von heterogenen Systemen genugt, um Permeabilitatsdaten vorherzusagen. Eine ahnliche Handhabung der KERNER-Analyse kann angewandt werden, um die Moduli vorherzusagen. Die Analyse der Permeabilitats-Ergebnisse und der Moduli-Ergebnisse zeigt das Auftreten der Phasenumkehrung bei ahnlicher Zusammensetzung dieser Zweiphasen-Blockcopolymeren an.



Von einem gegebenen Blockcopolymeren konnen verschiedene physikalische Eigenschaften erhalten werden, wenn Polymerfilme aus verschiedenen Losungsmitteln hergestellt werden, oder wenn der Polymerfilm mit einem Losungsmittel fur nur eine Phase des Polymeren angequollen wird. Die Neigung der Polydime-thylsiloxan-Komponente zu kristallisieren, hiingt von der Flexibilitiit des Copoly-meren ab. Die Flexibilitiit kann bei der Herstellung des Filmes eingestellt werden.

Allen Noshay

Papers

Block Copolymers: Overview and Critical Survey

Preparation of low-density ethylene copolymers in fluid bed reactor

Olefin polymerization catalysts adapted for gas phase processes

Process for producing stereoregular polymers having a narrow molecular weight distribution

Physical property characteristics of polysulfone/poly‐(dimethylsiloxane) block copolymers