Strong Separation Membranes

U.S. Patent 9,381,449 (July 5, 2016), “Carbon Nanotube Composite Membrane,” Carl W. Sims and Quan Liu (Idex Health & Science LLC, Rohnert Park, Calif., USA).

Polymers can form useful separation membranes. However, the fragility of thin membranes required for reasonable flow poses a serious problem. Sims and Liu developed strong composite separation membranes based on coated nonwoven fabrics of intermingled closed carbon nanotubes. The fabric is dip coated with a sulfonated tetrafluoroethylene and ionomer solution resulting in a non-porous, permeable, strong composite membrane. The fabric is single or multiple layers and the carbon nanotubes are randomly intermingled.

Lighter Antiballistic Protection

U.S. Patent 9,381,728 (July 5, 2016), “Composite Material: A Ballistic-Resistant Article Made from Same and Method of Making the Article,” Jeffrey Alan Hanks, Brian Charles West and John Henry McMinn (E.I. Du Pont De Nemours & Co., Wilmington, Del., USA).

Anti-ballistic armor based on high-tenacity polymeric yarns have been in use for some time. However, there is a continuing need for lighter hard body armor with increased resistance to bullets and fragments. Hanks, West and McMinn developed a fiber-reinforced resin composite for ballistic protection consisting of multiple plies of a woven fabric and resin. The impregnating resin is 5 to 30 wt % of the total composite and the fabric deformed. The composite may have a third ply with a surface area no greater than 50% of the surface area of the first and second ply. The ratio of the number of first and second plies to the number of third plies is from 2:1 to 12:1.

Repairing Large Composite Structures

U.S. Patent 9,381,707 (July 5, 2016), “Repair of Composite Materials,” Daniel Thomas Jones, Andrew James Passey and Iain James Cranwell (Gurit Ltd., Newport, Isle of Wight,UK).

Fiber-reinforced resin structures periodically require repair. Some, such as wind turbine blades, are so large they have to be repaired on-site in the field. Jones, Passey and Cranwell developed prepreg repair patches consisting of fibrous reinforcement layers partially impregnated with a mixture of matrix resins with different viscosities and coated with a wet resin curable by ultraviolet radiation. The patch is covered with a removable flexible polyethylene or polyethylene terephthalate film preventing premature curing. The fibers can be woven or nonwoven glass, carbon or aramid fibers.

Transparent PVC Materials

U.S. Patent 9,382,406 (July 5, 2016), “Vinyl Chloride Resin Composition for Transparent Products,” Ryusuke Mitamura, Tadashi Sengoku and Kazumasa Tanaka (Adeka Corp., Tokyo, Japan).

Vinyl chloride (PVC) materials have many different uses because properties can be adjusted with soluble plasticizers. However, many building materials are hard PVC materials with little or no plasticizer. PVC materials degrade the environment and are not color stable or transparent. Heat stability and weather resistance also are needed in many applications. Mitamura, Sengoku and Tanaka developed a stable, transparent PVC material consisting of 100 parts by weight PVC, 0.01 to 10 parts zinc salts, 0.01 to 10 parts zinc-modified hydrotalcite compounds, and 0.01 to 3 parts phosphite ester compounds. These materials can show glass-like transparency and are used in industrial boards, decorative boards, trays, film, shrink film, sheets, building materials, water pipes, plates, joints, hoses, bottles and automotive materials.

Composite Bone Anchors

U.S. Patent 9,386,977 (July 12, 2016), “Composite Anchor,” Richard M. Lunn and David A. Paulk (Smith & Nephew Inc., Memphis, Tenn., USA).

Arthroscopic procedures often require soft tissue to be reattached to bone using bone anchors. These require holes drilled in the bone, further complicating the surgery. Lunn and Paulk developed a composite anchor based on an absorbable polymer and non-absorbable metal. This anchor consists of a top absorbable layer and a bottom conical, threaded metal and can have a hole for an attached suture. The structure is anchored to the bone by rotating and pressing the metal part into the bone. The resin is a nonabsorbable polyetheretherketone filled with absorbable fillers such as calcium compounds. The metallic base is stainless steel or titanium.

Oil Spill Sorbents

U.S. Patent 9,388,289 (July 12, 2016), “Open-Cell Foam for the Selective Absorption of Oil from Water,” Shahab Shojaei-Zadeh and Michael Fechtmann (Rutgers University, New Brunswick, N.J., USA). 

Oil spills have tremendous negative environmental and economic impact and are extremely costly and time consuming to clean up. Absorbent materials can be used in clean-up. Though oil and water are immiscible, most porous, spongy materials readily absorb both oil and water, making non-selective absorbent materials uneconomical for oil cleanups. Shojaei-Zadeh and Fechtmann fabricated microporous, open-cell foam of a hierarchical structure from a mixture of a foamable liquid polymer such as silicone rubber, a curing agent, a blowing agent and a filler. Blowing agents include aliphatic alcohols, and porogen fillers consist of water-soluble powdered carbohydrate, sodium chloride and sodium bicarbonate. The components are mixed, heated to cure the mixture, and porogens are removed by extraction. The result is a microporous, hydrophobic, open-cell polymer foam that absorbs hydrocarbon oils and rejects water. The pores have pore diameters 10 microns and greater. Mixing the liquid blowing agent with the porogen before adding to the liquid rubber is critical to pore formation.

Rotational Molding Crosslinked Polyethylene

U.S. Patent 9,388,296 (July 12, 2016), “Crosslinked Polyethylene Composition having Improved Processability,” Xuelian Chen, Wenbin Liang, Yanhua Niu and Shih-yaw Lai (National Institute of Clean and Low-Carbon Energy, Beijing, China, and Shenhua Group Corp. Ltd., Beijing, China).

Large and hollow polyethylene articles are usually produced by rotational molding. Crosslinked polyethylene materials are especially difficult to mold by any method, including rotational molding. Chen et al developed a processable crosslinked polyethylene consisting of 100 parts by weight of polyethylene, 0.03 to 5 parts of crosslinking agent, 0.03 to 5 parts crosslinking promoter and 0.01 to 1.5 parts free radical inhibitor. The polyethylene contains at least 90 wt % vinyl and C₃-C₈ alpha-alkenyl groups with a density of 0.920-0.970 g/cm³ and a melt index of 2.5-17.5 g/10 min. The crosslinking agent is a peroxide and the crosslinking promoter contains maleimido, (meth)acrylate or allyl groups. The free radical inhibitor is an organic antioxidant such as a quinhydrone. The crosslinked polyethylene material shows adequate crosslinking retardation time for rotational molding.

Microporous Materials

U.S. Patent 9,393,548 (July 19, 2016), “Rapid and Enhanced Activation of Microporous Coordination Polymers by Flowing Supercritical CO₂,” Adam J.Matzger, Baojian Liu and Antek G. Wong-Foy (University of Michigan, Ann Arbor, Mich., USA).

Microporous coordination polymers (MCPs) can be high-performance sorbents. A number of synthetic issues make activation difficult and costly. These porous materials tend to be unstable and collapse during activation. Matzger, Liu and Wong-Foy used flowing supercritical CO₂ to activate metal organic framework materials (MOF). These porous materials are formed by combining a metal salt and an organic linker in a solvent such as N,N dimethylformamide, reacting to form a porous metal-organic framework and extracting solvent by flowing supercritical carbon dioxide through the material to remove occluded solvent from the crystals and activate the structure.  

Solid State Drawing

U.S. Patent 9,393,735 (July 19, 2016), “Solid State Drawing Laminated Polymer Billets,” Hoang T. Pham, Mark A. Barger, Kevin L. Nichols, Brett M. Birchmeier and Andrew T. Graham (Eovations LLC, Grand Rapids, Mich., USA).

Properties of polymeric materials can be improved by stretching or drawing the solid state. Drawing large cross-sectional dimensions is difficult and cumbersome. Drawing temperatures require cooling or heating which can be time consuming and expensive. Pham et al solid-state-stretched a laminated polymer billet containing two or more polymer compositions laminated to one another by extrusion. The first polymer is extruded and cooled. The second polymer is extruded onto the first polymer forming the billet. The two-step extrusion greatly simplifies conditioning for drawing. Candidate polymers include polypropylene, polyethylene, polyester and polyvinyl chloride. This process can be used to produce items such as railroad ties, large planks, telephone poles, siding, decking materials, fencing materials, decorative trim materials and wood replacements.

Toughened Vinyl Thermosets

U.S. Patent 9,394,427 (July 19, 2016), “Toughening Crosslinked Thermosets,” Giuseppe R. Palmese, John J. LaScala, James M. Sands and Xing Geng (U.S. Army, Washington, D.C., and Drexel University, Philadelphia, Pa., USA).

Vinyl ester resins are the most popular resin systems used in polymer matrix composite fabrication for military and commercial applications due to their good properties, low weight and low cost. However, like other thermoset resins, unmodified vinyl esters suffer from brittleness and low resistance to fracture limiting their application. In addition, vinyl ester and unsaturated polyester resins contain styrene, a hazardous air pollutant and carcinogen. Palmese et al developed grafted triglycerides comprising an acrylated triglyceride grafted with a fatty acid residue containing 4 to 28 carbon atoms. A grafted triglyceride is mixed with vinyl ester resins and cured. This method also includes use of the grafted triglycerides to make toughened resin and composite systems with reduced hazardous air pollutants without reducing the glass transition temperature or increasing the viscosity.

Stretchable Transistors

U.S. Patent 9,401,487 (July 26, 2016), “Channel Layer for Stretchable Transistors,” Jung-kyun Im, Jong-jin Park, Min-woo Park, Min-kwan Shin and Un-yong Jeong (Samsung Electronics Co. Ltd., and Industry-Academic Cooperation Foundation, Yonsei University, Seoul, South Korea).

Most electronic devices are based on a silicon substrate. A thin-film transistor (TFT) is an active element and is a necessary component in display devices. As electronic technology develops, TFT devices will be a necessary component in next-generation devices requiring transparency, flexibility and stretchability. Unfortunately, silicon materials cannot be used in stretchable electronics. Im et al formed a stretchable TFT by casting a solution of an elastomer, an organic semiconductor and a solvent. Candidate polymers include a polybutadiene /styrene copolymer, an ethylene propylene diene rubber, an acrylic rubber, a polychloroprene rubber, a polyurethane, a fluoro-rubber and a butyl rubber. The rubber and semiconductor is dissolved in a solvent, deposited on a substrate such as a paper and annealed. The elastomer is the stretchable matrix and the semiconductor is the electroconductive network.