Materials

Soft-Bake Purification of SWCNTs Produced by Pulsed Laser Vaporization

A more efficient, cost-effective, environmentally friendly method purifies high-quality carbon nanotubes. The “soft-bake” method is a simple and reliable initial purification step first proposed by researchers at Rice University for single-walled carbon nanotubes (SWCNT) produced by high-pressure carbon mon - oxide disproportionation (HiPco). Softbaking consists of annealing as-produced (raw) SWCNT, at low temperatures in humid air, in order to degrade the heavy graphitic shells that surround metal particle impurities. Once these shells are cracked open by the expansion and slow oxidation of the metal particles, the metal impurities can be digested through treatment with hydrochloric acid.

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Improved Wide Operating Temperature Range of Li-Ion Cells

Applications include electric vehicles, where high-energy-density and high-power batteries are needed that can operate at low temperature. Future NASA missions aimed at exploring the Moon, Mars, and the outer planets require rechargeable batteries that can operate over a wide temperature range (–60 to +60 ºC) to satisfy the requirements of various applications including landers, rovers, penetrators, CEV, CLV, etc. This work addresses the need for robust rechargeable batteries that can operate well over a wide temperature range.

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Environmental Awareness Leads to PVC-Free Assemblies

Totally PVC-free products provide an environmentally safer alternative. Over the last several years, the medical industry has become more aware of the toxic side effects of polyvinyl chloride (PVC). The American Public Health Association passed a resolution in November 2011 urging hospitals, schools, and nursing homes to reduce the amount of PVC they use.

Posted in: Bio-Medical, Manufacturing & Prototyping, Custom & Contract Manufacturing, Materials / Adhesives / Coatings, Materials, Plastics, Medical, Briefs, MDB

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Prosthetic Foot Uses Unique Aerospace Material

A new space-age material creates a prosthetic foot that’s built to last. Formerly used only in the aerospace arena, Flexeon is a radical departure from the rigid carbon fiber materials found in most prosthetic feet. It’s a specially- formulated reinforced fiberglass material that is nearly indestructible, extremely flexible, and available exclusively on Ability Dynamic prosthetic devices, such as the RUSH™ foot. Flexeon underwent thorough and extensive testing for flexibility, material strength, and durability in prosthetic labs, as well as on patients aged 21 to 69 in clinical trials. The results of these tests and trials revealed that this high-tech material is three times more flexible than carbon and much more durable than current standard carbon fiber products.

Posted in: Bio-Medical, Manufacturing & Prototyping, Implants & Prosthetics, Materials / Adhesives / Coatings, Materials, Composites, Plastics, Medical, Briefs, MDB

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High-Temperature, Lightweight, Self- Healing Ceramic Composites for Aircraft Engine Applications

The use of reliable, high-temperature, lightweight materials in the manufacture of aircraft engines is expected to result in lower fossil and biofuel consumption, thereby leading to cost savings and lower carbon emissions due to air travel. Although nickel-based superalloy blades and vanes have been successfully used in aircraft engines for several decades, there has been an increased effort to develop high-temperature, lightweight, creep-resistant substitute materials under various NASA programs over the last two decades. As a result, there has been a great deal of interest in developing SiC/SiC ceramic matrix composites (CMCs) due to their higher damage tolerance compared to monolithic ceramics. Current-generation SiC/SiC ceramic matrix composites rely almost entirely on the SiC fibers to carry the load, owing to the premature cracking of the matrix during loading. Thus, the high-temperature usefulness of these CMCs falls well below their theoretical capabilities.

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Treatment to Control Adhesion of Silicone-Based Elastomers

Ultraviolet radiation is used to control and decrease the level of adhesion. Seals are used to facilitate the joining of two items, usually temporarily. At some point in the future, it is expected that the items will need to be separated. This innovation enables control of the adhesive properties of silicone-based elastomers. The innovation may also be effective on elastomers other than the silicone- based ones. A technique has been discovered that decreases the level of adhesion of silicone-based elastomers to negligible levels. The new technique causes less damage to the material compared to alternative adhesion mitigation techniques.

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High-Temperature Adhesives for Thermally Stable Aero-Assist Technologies

These adhesives feature high thermal conductivity and increased thermal decomposition temperature. Aero-assist technologies are used to control the velocity of exploration vehicles (EVs) when entering Earth or other planetary atmospheres. Since entry of EVs in planetary atmospheres results in significant heating, thermally stable aero-assist technologies are required to avoid the high heating rates while maintaining low mass. Polymer adhesives are used in aero-assist structures because of the need for high flexibility and good bonding between layers of polymer films or fabrics. However, current polymer adhesives cannot withstand temperatures above 400 ºC.

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