For full functionality of this publication it is necessary to enable Javascript.

Superhydrophobic Surfaces

U.S. Patent 8,707,999 (April 29, 2014), “Method for Fabricating Solid Body Having Superhydrophobic Surface Structure and Superhydrophobic Tube Using the Same Method,” Dong-Hyun Kim, Sang-Min Lee, Il-Sin Bae, Dong-Seob Kim, Duk-Hyun Choi, Chang-Woo Lee, Ji-Hoon Jeon, Seong-Ho Son, Tae-Chul Moon, Woon-Bong Hwang, Joon-Won Kim¸ Hyun-Chul Park, and Kun-Hong Lee (Postech Academy-Industry Foundation, Kyungsangbuk-do, South Korea).

Superhydrophobic surfaces can greatly increase the efficiency of many fluid transfer processes, from reduced window condensation to optimized ship propellers. The surfaces are based on nanometer surface protusions and depressions usually formed by difficult and expensive methods.

Kim et al. developed superhydrophobic fluid transfer guides by casting. The desired surface is formed by immersing a metal body with nanometer holes formed by anodizing into a non-wetting polymer melt such as PTFE, FEP, or PFA. The polymer solidifies, and the resulting solid film with the necessary surface structure is removed and placed on a support structure, forming the fluid guide.

Soundproofing

U.S. Patent 8,708,097 (April 29, 2014), “Acoustic Panel,” Mark Borroni (Bellmax Acoustic Pty Ltd., Surrey Hills, Australia).

Most sound absorbers in buildings are ineffective because they can absorb only a limited number of different sound frequencies. Borroni developed a sound-absorbing panel with the look and feel of conventional plaster board based on an impermeable membrane covering a layer of clusters of sound-absorbing cavities. These clusters have different vibration resonances enabling sound absorption of a wide variety of different sound frequencies. This absorbing panel consists of a paper membrane attached to a layer of polyester fibers with many cavities and about 33% open area. The result is two prominent absorption peaks at 300 and 1700 Hz. These panels are suitable for automotive and roadside barrier applications.

Recyclable Pumps

U.S. Patent 8,708,200 (April 29, 2014), “Disposable Pump with Suck-Back Mechanism,” Hugo Nilsson (SCA Hygiene Products AB, Gothenburg, Sweden).

Small-scale dispensers of liquids, such as detergents, are popular and involve a variety of dispensing mechanisms. The most effective are pumps with collapsible containers. However, they are relatively expensive, with components of different materials, and are not easily recyclable.

Nilsson designed a disposable pump based on collapsible containers using blow molded and injection molded recyclable polypropylene or high-density polyethylene. The pump consists of a pressure chamber with input and output valves, one for input liquid from the container and one for the output spray. All materials for a particular container and pump are the same—and recyclable.

Fail-Safe Structures

U.S. Patent 8,708,281 (April 29, 2014), “Method of Slowing the Propagation of Cracks in a Fail Safe Structure and Fail Safe Frame, Especially for Fuselage,” Julien Guillemaut (Airbus Operations SAS, Toulouse Cedex, France).

A key to fail-safe materials is different paths for load response. Present designs of aircraft fuselages are based on only a metal structure that develops cracks of different sizes. Fail-safe performance can be enhanced by adding other effective crack-initiation and propagation mechanisms.

Guillemaut developed a fail-safe structure based on a metal frame attached to composite plates. These plates redistribute the mechanical load from the stress site to the other components, and supply different failure mechanisms. The structure consists of metal longerons (stiffeners) with carbon-fiber epoxy soles and fish plate straps connected to the frame.

Shape-Memory Coatings

U.S. Patent 8,710,166 (April 29, 2014), “Shape Memory Polymers Formed by Self-Crosslinking of Copolymers,” Tat Hung Tong (Cornerstone Research Group, Inc., Dayton, Ohio, USA).

Shape-memory polymers soften and harden quickly and repetitively on demand, returning to their memory structure. They can temporarily soften, change shape, and harden back to new shapes and forms. Shape memory polymer coatings can prevent damage and even repair cracked substrates.

Tong developed a castable coating based on self-crosslinking shape-memory polymers such as siloxane-acrylate polymers. The polymer contains a silane crosslinker added to acrylates, forming alkylsiloxyl groups in the acrylate copolymers. The degree of crosslinking is controlled by the number of siloxane groups in each polymer. Applications include self-healing coatings for vehicles and aircraft.

Foaming Polyester

U.S. Patent 8,714,401 (May 6, 2014), “Stretched and Foamed Plastic Container and Method of Producing the Same,” Kentarou Ichikawa, Nobuhisa Koiso, and Norio Akuzawa (Toyo Seikan Kaisha, Ltd., Tokyo, Japan).

Polyethylene terephthalate containers are widely used, but colorants and other additives make recycling difficult. Transparent containers without pigments would be more recyclable, but colored or opaque containers are sometimes necessary.

Ichikawa, Koiso, and Akuzawa developed opaque foamed polyester containers by injection molding a resin containing a foaming agent, followed by stretching. The stretching during solidification leads to foamed cells elongated in the stretch direction, with cells decreasing in size from the outside to the inner wall.

One problem is oxygen diffusion. This diffusion is minimized by keeping the inner wall solid without foamed cells. The thickness also increases, reducing diffusion and increasing light scattering.

PLA Foams

U.S. Patent 8,722,754 (May 13, 2014), “Extruded Foams Made with Polylactides that Have High Molecular Weights and High Intrinsic Viscosities,” James Nangeroni and Jed Richard Randall (NatureWorks LLC, Minnetonka, Minnesota, USA).

Polylactide polymers (PLA) are now available in commercial quantities. Attempts have been made to extrude this polymer into foam, but foaming PLA materials is difficult. Resins like PLA which have low melt strengths usually can be foamed only within a very narrow range of processing temperatures, if at all. Commercially, it’s not feasible to maintain such narrow operating ranges.

Nangeroni and Randall developed a pressurized, molten mixture of melt-processable branched polylactide (PLA) resins, containing about 2 to 20 wt% of physical blowing agent, which can be extruded to form a stable foam. The PLA resin has a weight-average molecular weight of 500,000-1,500,000 and an intrinsic viscosity of at least 1.40 deciliters/gram. The preferred resins have at least 8 to 15 branches per molecule. No more than 6 wt% of PLA resins have molecular weights of more than 3 million, and no more than 2 wt% have weights less than 30,000.

Soluble Polyimides

U.S. Patent 8,722,758 (May 13, 2014), “Water Soluble Polyimide Resin, its Preparation and Use,” Kuen Yuan Hwang, An Pang Tu, Sheng Yen Wu, Gai Chi Chen, Ching Jui Huang, and Jen Fu Wang (Chang Chun Plastics Co., Ltd., Taipei, Taiwan).

Polyimide film has been widely used as an insulator in electronics due to its flexibility, excellent insulation, and heat resistance. With advanced electronics, this application is growing. However, there is no easy way to apply an insoluble film to complex structures. Water-soluble polyimides are needed which can be applied as a coating using aqueous solutions rather than organic solvents. 

Hwang et al. developed water-soluble polyimides by adding hydrophilic functional groups such as -OH or -COOH groups using polyamic acid precursors having carboxyl or hydroxyl groups. The water-soluble resins have number-average molecular weights of 40,000-100,000 and excellent solubility in aqueous alkaline solutions.

Polymer-Dendrimer Hybrids

U.S. Patent 8,722,830 (May 13, 2014), “Polymer-Dendrimer Hybrids,” Jonathan Weaver, Steven Rannard, Gwenaelle Bonzi, and Andrew Cooper (University of Liverpool, Liverpool, Great Britain).

Divergent syntheses of dendrimers need to react with increasing numbers of surface functional groups on each growing molecule to form the next generation of the polymer. This slows the process and is difficult to maintain.

Weaver et al. avoided the drawbacks of conventional dendrites by avoiding a complex architecturally pure internal dendrimer structure, but still providing a large number of judiciously placed surface functional groups. They produced a branched vinyl polymer carrying dendrons, where the vinyl polymer is made from a monofunctional vinyl monomer. It’s branched by a difunctional vinyl monomer to one branch or fewer per vinyl polymer, to prevent gelation.

Polyethylene Materials

U.S. Patent 8,722,833 (May 13, 2014), “Multimodal Polyethylene Composition, Mixed Catalyst and Process for Preparing the Composition,” Jennifer Kipke, Shahram Mihan, Rainer Karer, and Harald Schmitz (Basell Polyolefine GmbH, Wesseling, Germany). 

Multimodal polyethylene materials with balanced properties are well known. For food packaging, a resin needs a proper balance between water vapor barrier and mechanical properties. But typical multimodal polyethylene compositions have a molecular weight distribution which is not adequately adjustable to cover the whole range of products needed for food packaging. 

Kipke et al. developed a polyethylene material with proper balance of three ethylene polymer fractions using non-single-site and single-site catalysts. The key to water vapor resistance is a sufficient number of oriented crystallites throughout the material.

Railroad Ties

U.S. Patent 8,727,228 (May 20, 2014), “Structure for Railroad Ties Having Data Acquisition, Processing and Transmission Means,” Torben Djerf and John D. Eisenhut (TJ Technology Holdings, LLC, Canton, Ohio, USA).

Railroad ties have traditionally been made of solid wood, which is chemically treated with a preservative such as creosote to discourage insect attack and biological degradation. Treated solid wood ties, however, have a relatively short useful life span of five to fifteen years.

Djerf and Eisenhut developed railroad ties consisting of a core of laminated wood slats inserted into an extruded sleeve of scrap tire rubber and polyurethane. A urethane adhesive is used as a lubricant and bonding agent.