Polymers™

Clamps have traditionally been used to control blood flow during surgical procedures. Now there is another option. A thermosensitive polymer material that can temporarily block blood flow during non-neurovascular procedures has been approved in the U.S., reports Andrew Turley in  Chemistry World . The water-soluble vessel occluder is called LeGoo. John Merhige from Pluromed, the company that makes this medical product, told Turley that LeGoo puts the vessels under less trauma than clamps and maintains the shape of the vessel, making suturing more straightforward. Turley writes that “the key to the success of LeGoo is that the viscosity changes over a relatively narrow temperature range of only a few degrees.” At room temperature, it is a viscous liquid. At body temperature, it forms a solid gel. When injected into a blood vessel in the heart surgery below, LeGoo can halt blood flow for about 10 minutes or until cooled back a liquid by applying ice. The active ingredient i...

Two reports indicate that the U.S. recycling volume of polyethylene terephthalate (PET) went up in 2010, and the country’s recycling rate rose for the seventh consecutive year. The plastic recycling industry’s annual all-bottle recycling rate report was released by the American Chemistry Council and the Association of Postconsumer Plastic Recyclers (APR). It includes data on PET and high-density polyethylene bottles and containers, which is the second most recycled plastic. Total plastic bottle recycling rate was 28.8%, up from 27.8% in 2009, and total pounds of plastic bottles collected increased by 123 million pounds for 2010 over 2009, with increases for PET, high-density polyethylene (HDPE), and polypropylene bottle resins, according to the report. The numbers on recycling of post-consumer PET containers were presented in a report from the National Association for PET Container Resources (NAPCOR), APR, and the PET Resin Association. Mike Verespej, Washington, D.C. correspon...

Fur is the hot fashion for the upcoming cold winter season. Fake fur, that is. And it’s more exotic, realistic, durable — and even profitable — than ever before thanks to advances in polymer   chemistry and manufacturing processes. Melissa Magsaysay of the  Los Angeles Times  reports that “stores and online sites, including high-end designer brands and mass-market retailers, are full of garments with materials that look like mink, cheetah or beaver.” Aislinn Sarnacki for the  Bangor Daily News  writes that “today, the finest faux pelts are difficult to distinguish from the natural furs it imitates, save for the fact that much of it is dyed hot pink and electric blue.” Magsaysay adds that faux fur is not just a fad that “could please fur-coveting consumers and possibly assuage a few concerns of animal rights activists.” Although faux fur is usually significantly less expensive than real fur, the faux fur business is making money. According to the  ...

The search is on to find biodegradable  plastics  that can be made from renewable materials at reasonable costs. Now, researchers in Germany have reported a method for rapidly producing poly-3-hydroxybutyrate (PHB) in microalgae. PHB is renewable and biodegradable polyester with thermoplastic properties. PHB is produced naturally in bacteria such as  Ralstonia eutropha  and  Bacillus megaterium  without petroleum feedstock. And it degrades to carbon dioxide and water, unlike other plastics that may never degrade. Researchers are exploring various ways to use algae for making more environmentally friendly and sustainable plastic, as shown in the video. Companies have produced PHB, but the bacterial fermentation methods are expensive, and plant systems grow slowly and occupy the agricultural land area. Bacteria synthesize PHB from acetyl-CoA using the enzymes ß-ketothiolase, acetoacetyl-CoA reductase, and PHB synthase. The bioplastic accumulates in ...

United Parcel Service of America, Inc. (UPS) was looking to cut fuel costs for its delivery trucks. The company has a few thousand plug-in electric and natural gas-powered vehicles in its 70,000-plus fleet, but batteries only go so far, and natural gas stations aren’t usually along rural routes. UPS was looking for a diesel-powered cargo van with increased fuel efficiency that could travel through city and country like the existing van. Turns out that Utilimaster Corp. and Isuzu Commercial Truck were developing just such a truck,  reports  Rhoda Miel at  Plastics News . Starting in 2008, Utilimaster and Isuzu began work on the Reach in response to customer requests for better fuel mileage. The new vehicle promises to be 35% more fuel-efficient than standard vans, which the designers estimate could save delivery companies $3,000 in fuel per vehicle, per year. UPS is currently testing modified versions of the Reach, “which has a composite skin, structural plastic fl...

Scientists at the University of California, Santa Barbara, Materials Research Laboratory have used an instrument called magnetic tweezers to stretch a polymer and measure its nanoscale structure and other properties. This work could lead to a modestly priced and rapid tool to screen for polymer properties with applications in drug delivery to renewable biomaterials, according to a press release. The work also validates a theory about polymer structure insolvent that was the basis for a Nobel Prize awarded in the 1970s. The UCSB researchers used their method to study polyethylene glycol (PEG), which is frequently used in cosmetics, adhesives, and medicines, and as a nonfouling coating agent for medical implants and sensors. They reported a framework for comparing biomolecules and synthetic polymers based on chain structure in a journal article earlier this fall. “Many companies are looking to replace the petroleum-based polymers they use in consumer products with polymers made...

Volcanic ash and coconuts aren’t just found on tropical beaches anymore. That is because Hyundai, Kia, and Ford are using them in automotive applications, which have been nominated for awards. “Engineers at Hyundai and Kia are using ground volcanic ash in a polypropylene and rubber composite to reduce costs and achieve a cloth-like appearance,” reports Doug Smock in  PlasticsToday . The new material looks like the cloth wrap found in higher-priced cars and is currently used on the pillar trim of the 2011 models of the Hyundai Elantra and the Kia Rio. It costs a few dollars more than its molded counterpart but is about half the cost of cloth wrap. In addition, it weighs less, has improved scratch resistance, and has reduced odor and volatile organic compound emissions. Joel Myers, a senior engineer at Hyundai, told  PlasticsToday  that “the goal of the project was to develop a pillar trim that looks better than non-painted injection molded pillars, which have a c...

Earlier this year, Xuanhe and colleagues at Duke University reported the mechanism that causes the breakdown of soft dielectric materials, such as polymers that insulate wires, that are continually exposed to electricity. Now, the researchers have demonstrated a way to improve performance and extend the life of those materials: wrap them with a rigid polymer. Scientists have been working for years to find a soft dielectric material that will not wear. Zhao suggests in a statement that the approach needs to change because it is a mechanical problem, not a materials issue.“We found that increasing voltage can cause polymers to physically crease and even crater at the microscopic level, eventually causing them to break down,” said Zhao, who is an assistant professor of mechanical engineering and materials science at Duke’s Pratt School of Engineering, in a statement. “So we thought if we wrapped the polymer tightly, that would prevent this creasing from occurring. Experiments proved...

Scratches in table lacquer or automotive paint that fix themselves. Eyeglasses, toys, and other plastics that go back together without glue and by simply holding the two pieces back together. The science of self-healing polymer can make those situations reality. Science correspondent Richard Gray writes in the U.K.’s  The Telegraph  about scientists at the chemical company AkzoNobel and the Eindhoven University of Technology in the Netherlands who are working on a supramolecular polymer that requires just a bit of mechanical force to repair when broken. Other researchers have developed materials that fall into the category of self-healing polymers. For example, some of the materials can be “fixed” by exposing the material to a UV light or when microcapsules in the material burst open.This new polymer can be cut apart completely, pushed back together with bare hands, and be as strong as before the cut. Bert Meijer, a materials engineer at the Eindhoven University of T...

A research team has developed the world’s most efficient organic light-emitting diodes (OLEDs) on plastic, and the devices provide comparable performance to traditional glass-based OLEDs, according to a press release from the University of Toronto in Canada. “This discovery unlocks the full potential of OLEDs, leading the way to energy-efficient, flexible and impact-resistant displays,” said research team leader Zheng-Hong Lu in a statement. The researchers reported the results in the journal  Nature Photonics . OLEDs are essentially dye materials that can be activated by electricity. They are already used in some cell-phone displays and other small-scale applications and are on-track to dominate the advanced electronic screen market, according to the press release. OLEDs are appealing for making large energy-efficient, high-contrast displays, and lighting, including lighting designs that are printed with newspaper machines and applied like wallpaper. Current OLEDs are ma...

Innovative medical devices could improve health care and lower costs. Penn State Erie, The Behrend College opened a Medical Plastics Center (MPC) in Erie, Pennsylvania, with that mission in mind. MPC offers a fabrication and testing facilities and a unique certification for undergraduate students, writes Doug Smock in  PlasticsToday . Ralph Ford, the director of the engineering school, told Smock: The purpose of the new center is to provide specialty education for plastics engineering technology students and to conduct research in the medical plastics field with industry partners. Smock gives more details on MPC: The MPC will house a dedicated medical plastics lab that features an ISO Class 8 cleanroom, a 55-ton liquid silicone injection molder, a materials compounding extruder, autoclave sterilization, and injection molding machines with up to 200 tons of clamping force. The center can accommodate impact, moisture, creep and melt index testing along with circuit boa...

Manufacturers have been housing charging stations for electric cars in steel or aluminum so far, but those materials do not meet all of the needs of the increasingly sophisticated insides of charging stations. As the demand for charging stations grows, developers are using plastic materials, including wood-plastic composites and polycarbonate resins, for protective exterior covers. Researchers at the Fraunhofer Institute for Mechanics of Materials IWM in Germany and industrial partner Bosecker Verteilerbau Sachsen are developing honeycomb panels from wood-plastic composites for exterior covers for charging stations, according to  EcoComposites . The composites are made of roughly 70% wood fiber and 30% thermoplastic polypropylene. Because the material can be formed into any shape and is used mostly for constructing weather-resistant decks and patio furniture, modular chargers could be designed to blend into street benches or bus shelters. The composites are recyclable, and ...

Why send a person to do a dangerous job when a polymer can do it without facing hazard? A new sensor device made of polymer nanofibers could monitor the safety and integrity of buildings during earthquakes, writes Holly Sheahan for  Chemistry World . Strain sensors in buildings, vehicles or aircraft are not new, but this approach is, according to Sheahan’s reporting. Most sensors have inorganic components that are stiff and can be difficult to fit into small spaces. Guojia Fang and co-workers from Wuhan University in China have fabricated their device with flexible polymer fibers. Using electrospinning, the researchers made the fibers out of a mixture of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT: PSS) and polyvinyl alcohol (PVA). After forming a fiber network and applying it to a substrate, the researchers encapsulated everything with a layer of polydimethylsiloxane. To test how the device reacted to small movements, they attached the device to a team ...

Refractive index is a measure of how fast light passes through a given medium. Scientists and engineers who have harnessed this property — along with a related property called the extinction coefficient — have revolutionized the telecommunications industry in the past century. But making transparent materials with tunable refractive indexes that don’t lose photons along the way has not been easy. Now, Natalie at Imperial College in London and coworkers have reported in a journal article “a hybrid material that can be readily produced in water via a one-pot synthesis directly from commercially available, low-cost precursors.” Their synthesis makes a hybrid polymer/inorganic material that results in thin films, dielectric filters, and lenses with tailored dimensionality, processability, and functionality writes Jenny Mahoney in  Materials Views . Crystalline inorganics have traditionally been used to provide a high refractive index, but they make the material opaque, so Nat...