Institut de chimie. Produire des polymères biodégradables en grande quantité, en alternative aux plastiques issus du pétrole, reste un enjeu écologique et industriel majeur.
Des chercheurs de l’Institut de Recherche de Chimie de Paris (CNRS/PSL/ParisTech) et du Laboratoire de physique et chimie des nano-objets (CNRS/INSA/Université Paul Sabatier) ont relevé le défi : ils ont mis au point une méthode originale pour synthétiser l’un de ces polymères biodégradables – le polylactide – de manière simple, énergétiquement et financièrement économe.
De quoi encourager la fabrication de cette catégorie de plastiques plus respectueuse de l’environnement. Ces travaux sont parus dans la revue Journal of the American Chemical Society. Produire des polymères biodégradables pour fabriquer des plastiques est encore très couteux. Actuellement, un seul polymère peut être synthétisé à un cout suffisamment bas pour l’être en grande quantité : le polylactide. Référence. Polyurea - Wikipedia. Polyurea is a type of elastomer that is derived from the reaction product of an isocyanate component and a synthetic resin blend component through step-growth polymerization.
The isocyanate can be aromatic or aliphatic in nature. It can be monomer, polymer, or any variant reaction of isocyanates, quasi-prepolymer or a prepolymer. The prepolymer, or quasi-prepolymer, can be made of an amine-terminated polymer resin, or a hydroxyl-terminated polymer resin. Polymer structure Time Crystals Are Now A Thing. Scientists have developed "time crystals", and while the name sounds like something from Doctor Who, they are very real, although they have nothing to do with time travel.
In the same way that a regular crystal has a structure that repeats regularly in space, time crystals have a structure that repeats itself in time. In a paper published in Physical Review Letter, American researchers led by UC Berkeley's Norman Yao discuss how to make and measure the properties of time crystals. Diamond vise turns hydrogen into a metal, potentially ending 80-year quest. Last October, Harvard University physicist Isaac Silvera invited a few colleagues to stop by his lab to glimpse something that may not exist anywhere else in the universe.
Word got around, and the next morning there was a line. Throughout the day, hundreds filed in to peer through a benchtop microscope at a reddish silver dot trapped between two diamond tips. HOME - formcard.com. CNRS INSIS - La soie d’araignée inspire des matériaux hybrides. Shape-Shifting Material Can Lift 1,000 Times Its Own Mass. Le graphène, un matériau miracle pour l'avenir de l'électronique.
Composé de carbone pur, le graphène se présente sous forme de feuilles aussi fines qu'un atome, ce qui en fait le matériau le plus mince au monde. Il est pourtant 100 fois plus résistant que l'acier, est très flexible et le meilleur conducteur électrique connu. Watch What Happens When A Snowball Is Encased In A Nickel-Based Superalloy, Then Dipped In Molten Steel.
“You've got a snowball’s chance in hell,” as the saying goes.
New Type of Carbon Is Harder and Brighter Than Diamonds. Scientists have designed a new type of carbon that is harder and brighter than naturally formed diamonds.
For those who want to wear a one-of-a-kind sparkler on their fingers, the new material, called Q-carbon, also gives off a soft glow. "This new phase is very unique," said study co-author Jagdish Narayan, a materials scientist at North Carolina State University. "It has novel electrical, optical and magnetic properties. " For instance, the material can act as either a metal or a semiconductor, and is magnetic at room temperature, he added. Japanese Scientists Invent "Unbreakable" Glass. Material Uses Insect Technology To Stay Dry Underwater. Objects that are kept underwater eventually succumb to the inevitable decay associated with being submerged – metal rusts, wood rots and human hands go all wrinkly.
Watch This Amazing Self-Healing Material That Could Instantly Repair Damaged Spacecraft. Disaster has struck.
A micrometeroid has hit the International Space Station (ISS), and the air inside has begun to rush out of the hole into the vacuum of space. But in a matter of seconds, before the station is destroyed, the hole seals itself and keeps the ISS and its crew intact. This is a future safety scenario that could be possible thanks to a remarkable new piece of research from scientists at the University of Michigan and NASA, published in the journal ACS Macro Letters. They have developed a material that, when punctured, can "fix" itself and temporarily stop air rushing out. Scientists Develop Self-Healing Airplane Wing. We’ve already had self-healing concrete, now welcome to the world of self-healing airplane wings.
After having worked quietly on the project for the past three years, a team of British scientists has now announced a new carbon fiber technology that, when damaged, can fix itself. This is the perfect solution for killing germs on public toilet door handles. The door handles of public toilets are probably one of the dirtiest spots in the universe. The average public toilet door handle contains 1,000 colony-forming units per milliliter of infection-causing bacteria, and I can tell you this is a lot. So, wouldn’t it be great if these festering germ-repositories had some kind of antibacterial mechanism?
Well, this is exactly what two Hong Kong teens thought, when they invented a self-sanitizing door handle that harnesses kinetic energy from door movement. The handle kills the germs through a combination of titanium oxide and UV rays Sun Ming Wong(17) and King Pong Li(18) developed an antibacterial door handle that generates all the energy it needs to sanitize itself from the movement of the door. This Alloy Can Withstand 10 Million Transformations. Scientists have created an alloy with a long memory, but it won't help you in a spelling bee. Its long memory is solely for returning to its original shape, no matter how much you bend and twist it.
This new alloy, made from the metal elements nickel, titanium and copper, has a property known as "ultra-low fatigue. " This means that the alloy can do millions of 'reps' without losing its original shape. The alloy, once bent, stays in that form until it is 'prompted' back to its initial form using heat. Five Synthetic Materials With The Power To Change The World. The New York World’s Fair of 1939-40 was one of the greatest expos the world had ever seen.
Visitors to Flushing Meadow Park in Queens were invited to see the “world of tomorrow” giving them a first glimpse of wonders such as the television, the videophone and the Ford Mustang. Le fil d'araignée n'est plus le matériau le plus solide du monde animal. SCIENCE Une étude montre que la dent de la patelle, une sorte d'escargot de mer, est le matériau naturel le plus résistant de la planète...
Circuit Scribe: Draw Circuits Instantly by Electroninks Incorporated. Graphene Armor Would Be Light, Flexible and Far Stronger Than Steel. Graphene Armor Would Be Light, Flexible and Far Stronger Than Steel Who needs science fiction? Nature is a wealth of imaginative plot twists. Take carbon. Carbon is common. It’s the fourth most abundant element in the universe. It’s the elemental keystone of terrestrial life. Experimenting with the one-atom-thick sheets of carbon known as graphene, Researchers at Rice University recently wrote the material’s properties make it exceptionally good at dissipating the energy of incoming projectiles.
Polymer Blend Conducts Heat Ten Times More Efficiently Than Conventional Plastics. While plastics have become an indispensable material in modern society, they are not very useful for certain applications because of how heat doesn't disappate from them easily. However, a group of material scientists have developed a polymer blend that not only exceeds the heat dissipation of other plastics, but is about ten times more efficient than conventional materials like metal and ceramic as well. The project was led by Kevin Pipe of the University of Michigan, and the paper was published in Nature Materials.
Plastics are synthetic polymers that are composed of repeating molecule chains. The amazing material that promises flexible displays, faster cars and bullet-proof suits: Buried within any battery are separators that govern the flow of the cell's electrolyte and electrons. Meet The Next Generation of Waste-Free Food Packaging. Researchers Develop Octopus-Inspired, Color-Changing Camouflage Material. Digital Metamaterials Get Us Closer to Invisibility Cloaks. New Crystal Can Absorb Huge Amounts Of Oxygen And Store It For Later. Humans need oxygen to breathe, but sometimes require concentrations higher than the 21% that is typically found in the air.
Supplementary oxygen has typically been associated with heavy, cumbersome oxygen tanks, but a new crystalline material might change that. Christine McKenzie of the University of Southern Denmark led a team that developed the material that is able to absorb and store oxygen at levels 160 times greater than air. The paper was published in the journal Chemical Science. Aérogel. Un article de Wikipédia, l'encyclopédie libre. En 2012, des aérogels à base de polymères ont été synthétisés.
Scientist Creates Diamonds From Peanut Butter. Diamonds are typically created more than 800 kilometers (500 miles) below Earth’s surface when temperatures over 2200 degrees Celsius (4000 degrees Fahrenheit) and pressure 1.3 million times greater than the atmosphere combine and crystallize carbon into the clear white stone we all know. Synthetic diamonds can replicate the process in a few short days, creating diamonds that are less politically-charged for use in jewelry, electronics, manufacturing, and more.