The Dow Chemical Company

Lu H Tung

Grace Y Lo

Douglas E Beyer

Jerald A Griggs

Ronald R Pelletier

Joseph W Rakshys, Jr

William A Gros

John F Vitkuske

Charles E Lyons

Ronald E Snyder

Jerry E White

Chieh-Chun Chau

Mary K Dehnke

Edward J Kramer

Larry L Kirkby

James E McGrath

David Y Chung

Charles E Reineke

Jerry L Hahnfeld

William C Pike

Jang-hi Im

Timothy E Long

Donald E Kirkpatrick

Kathleen M McCreedy

Otto C Raspor

C C Chau

Joseph J Randazzo

Allan D Broske

Timothy G Bee

Billy E Burgert

Grace Y-s Lo

Raymond W Tang

Photolytically crosslinkable thermally stable compositions comprising at least one crosslinkable polymer and a crosslinkable quantity of a multifunctional 3,4-disubstituted maleimide. The compositions may be employed to prepare adhesives and photo printing mats.

Photolytically crosslinkable thermally stable composition

A process for producing a branched polymer from a vinyl aromatic monomer comprising:

Preparation of branched polymers from vinyl aromatic monomer

Disclosed are bituminous blends having improved toughness and elasticity. The blends contain a bituminous binder and a tapered block copolymer formed from a monovinyl aromatic compound and a conjugated diene. Suitable tapered block copolymers include a tapered A-B-A type block copolymer of the A-t-B-t-A configuration, particularly those having an isolated monovinyl aromatic compound content of about 20 to about 90 weight percent, and tapered A-B-A type block copolymers of the A-B-t-A configuration having an isolated monovinyl aromatic compound content of about 20 to about 90 weight percent of the total monovinyl aromatic compound in the tapered block copolymer. Further disclosed is a method of making the blends. Further disclosed is a tapered A-B-A type block copolymer having an isolated monovinyl aromatic compound content of about 29 to about 75 weight percent.

Tapered block copolymers

Novel diene/methacrylate ester block polymers, especially tertiary butyl methacrylate ester block polymers are uniquely prepared at near ambient temperatures and capable of being hydrolyzed and neutralized to yield the corresponding methacrylic acid and methacrylic acid salt (ionomer) derivatives. The compositions are usefully employed in the preparation of thermoplastic elastomers, adhesives and laminating films.

Block polymers containing methacrylic acid and derivatives thereof

Bituminous compositions and method of making

Disclosed are bituminous blends having improved toughness and elasticity. The blends contain an emulsion of a bituminous binder and an emulsion of a tapered block copolymer formed from a monovinyl aromatic compound and a conjugated diene. Suitable tapered block copolymers include a tapered A-B-A type block copolymer of the A-t-B-t-A configuration, particularly those having an isolated monovinyl aromatic compound content of about 20 to about 90 weight percent, and tapered A-B-A type block copolymers of the A-B-t-A configuration having an isolated styrene content of about 20 to about 90 weight percent of the total monovinyl aromatic compound in the tapered block copolymer. Also disclosed is a method of applying the blends to various surfaces.

Bituminous compositions and methods of application to surfaces

Tapered block copolymers of monovinylidene aromatic monomers and conjugated diene monomers having an isolated polymerized monovinylidene aromatic content of from 30 to 75 percent, hydrogenated derivatives thereof and a process for their preparation.

Narrow molecular weight telechelic and/or block copolymers are prepared by anionic polymerization using multifunctional lithium initiator in combination with a C.sub.2-16 lithium alkoxide.

Polymerization process and initiator system therefor

Tapered block copolymers of monovinylidene aromatic monomers and conjugated diene monomers having an isolated polymerized monovinylidene atomatic content of from 30 to 75 percent, hydrogenated derivatives thereof and a process for their preparation.

A thermoplastic blend useful for the preparation of molded articles comprising a thermoplastic polymer and a tapered triblock elastomer of a monovinylidene aromatic monomer and butadiene having a melt index (condition 200/5.0 ASTM method D1238-82) of 0.5 to 60 and an average molecular weight from 50,000 to 135,000.

Polymer blends of tapered styrene-butadiene triblock thermoplastic

A method for preparing an asymmetric, semi-permeable membrane containing a uniform microporous structure for gas and liquid separation, including forming a dense separation on one major surface of a microporous support structure. The microporous support structure is initially formed as a solid unitary film, fiber or sheet by the simultaneous extrusion of at least two streams of heat-plastified polymeric materials including at least two differentially soluble polymeric materials. The separation layer can be formed on the support structure prior to or after the soluble polymeric material has been dissolved out of, as by leaching from the solid support structure to form the microporous support for the separation layer. Preparation in this manner greatly reduces the tendency to form undesiralbe pinholes in the membrane.

Method for preparing an asymmetric semi-permeable membrane

Asymmetric membranes are prepared by treating a major surface of a glassy polymer composition to render the surface resistant to solvent crazing and then contacting the glassy polymer composition with a crazing solvent. The crazing solvent permanently deforms the glassy polymer composition by forming a microporous structure on the untreated surface. The treated surface becomes the dense, discriminating layer of the membrane which achieves desirable permeation selectivity. The methods of treatment are (1) crosslinking, (2) providing an agent which renders the surface resistant to crazing, and (3) providing an agent which reacts with the surface. Additionally, the glassy polymer composition can be crosslinked before or after it is crazed to increase the mechanical strength of the membrane.

Membranes containing microporous structure

Semipermeable membranes with improved permeation flux are prepared by contacting a glassy polymer in the form of a hollow fiber or film with a solvent in which the polymer swells at conditions which permit the swelling solvent to diffuse into the glassy polymer and then stretching the swollen polymer in an amount sufficient to cause visible stress whitening.

Method for preparing semipermeable membrane compositions

A pressure sensitive adhesive composition is provided. The adhesive comprises an ABA block polymer wherein A represents a copolymer of styrene and alpha-methylstyrene and B represents blocks of diene polymer. The diene polymer can be butadiene, isoprene or a mixture thereof. The composition also contains a tackifying resin.

Growing community of inventors

Midland, MI, United States of America

Lu H Tung