Carbon dioxide may be used like a solvent to impregnate molded articles with pigments, antimicrobials, or other chemicals. One big advantage is that chemicals are embedded in the polymer structure, not just applied on the surface like a paint. The process may also be less expensive than compounding pigments or other chemicals into an entire molded part.
Researchers at the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT in Oberhausen, Germany are testing how carbon dioxide can be used to impregnate plastics. They say that carbon dioxide goes into a supercritical state that gives the gas solvent-like properties at a temperature of 30.1C and a pressure of 73.8 bar. In this state, carbon dioxide can act as a “carrier” in which dyes, additives, medical compounds and other substances can be dissolved.
“We pump liquid carbon dioxide into a high-pressure container with the plastic components that are to be impregnated, then steadily increase the temperature and the pressure until the gas reaches the supercritical state,” says Manfred Renner, a scientist at Fraunhofer UMSICHT. “When that state is reached, we increase the pressure further. At 170 bar, pigment in powder form dissolves completely in the CO2 and then diffuses with the gas into the plastic. The whole process takes a few minutes. When the container is opened, the gas escapes through the surface of the polymer but the pigment stays behind and cannot subsequently be wiped off.”
Many of the new adhesives we're featuring in this slideshow are for use in automotive and other transportation applications. The rest of these new products are for a wide variety of applications including aviation, aerospace, electrical motors, electronics, industrial, and semiconductors.
A Columbia University team working on molecular-scale nano-robots with moving parts has run into wear-and-tear issues. They've become the first team to observe in detail and quantify this process, and are devising coping strategies by observing how living cells prevent aging.
Many of the new materials on display at MD&M West were developed to be strong, tough replacements for metal parts in different kinds of medical equipment: IV poles, connectors for medical devices, medical device trays, and torque-applying instruments for orthopedic surgery. Others are made for close contact with patients.
New sensor technology integrates sensors, traces, and electronics into a smart fabric for wearables that measures more dimensions -- force, location, size, twist, bend, stretch, and motion -- and displays data in 3D maps.
As we saw on the show floor this week at the Pacific Design & Manufacturing and co-located events in Anaheim, Calif., 3D printing is contributing to distributed manufacturing and being reinvented by engineers for their own needs. Meanwhile, new fasteners are appearing for wearable consumer and medical devices and Baxter Robot has another software upgrade.
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