Polymers are Used in Increasingly Sophisticated Ways

Polymers have been a part of our lives for a long time. Amber, natural rubber,shellac, cellulose and many others puzzled earlier researchers, challenging them to find a way to reproduce the unique natural qualities in man-made products. Today we have along list: PVC, nylon, polyethylene, silicone, synthetic rubber, polystyrene and countless number of other chemical compositions that made out lives simpler, easier and more convenient. Some developments in this area have made major advancements reaching into the super-properties of metamaterialsHave you ever wondered: what’s new in this field?

Did You Know that there is a Polymer that Expands into Predetermined 3-D Shapes When Exposed to Water and UV Light?

Researchers from the University of Massachusetts and North Carolina State University have discovered a new polymer that curves, buckles and takes the desired shapes when exposed to radiation and water. University of Massachusetts team used a photographic lithography process in their experiment. Scientists exposed the polymer sheet to ultra-violet light and then to water. They have learned that when exposed to the UV light, the polymer molecules become cross linked and stable, with waterunable to cause the expansion in affected spot anymore! The sheets had a predetermined generic picture printed on them in such a way that UV light was only able to penetrate the areas of the sheet not covered with the dye; the dye was UV-protectant. When soaked in water after the exposure to the UV light, the sheets expanded repeating the shape of the print, creating the 3-D shape replica of the print. Also, in the areas where the layer of dye was thinner than normal, UV light penetrated little bit, causing smaller expansion in this area when soaked with water. They concluded that the expansion in water is reverse-proportionate to the amount of radiation received by the polymer. So far, scientists were able to create only basic shapes like cones and spheres, but their vision reaches biomedicine, robotics and micro-optics. Polymer based organs and implants could be delivered through the blood stream or surgically before they conform into desired shape.


Electrically Conductive Resin-Based Plastic

Resin-based material offered by Integral Technologies is 60% lighter than the lightest metal currently used as an electromagnetic shield in aerospace, automotive or marine applications. Electri-Plast CF66 is an electrically conductive, structurally fit, resin-based material composed of nickel-plated carbon fiber and polyamide-66 polymer. It is able to withstand high temperatures, corrosive fluids and persistent vibrations for extended period of time and is a great candidate to be used for electromagnetic shielding in engine compartments and other unfriendly environments. CF66 is just another example of plastics replacing metals in the areas previously dominated by metals.


About Polymer Synthesis and Repeat Units

Polymer is a bunch of monomers bonded covalently between each other into a chain or network. This monomer unit is called "monomer residue", or "repeat unit". Let’s take a look at the polymerization of polyester: in polyester, HOOC-C6H4-COOH (terephthalic acid) and HO-CH2-CH2-OH (ethylene glycol) form the repeating unit OC-C6H4-COO-CH2-CH2-O, which is terephthalic acid and ethylene glycol combined, minus two molecules of water. The structure of the repeat unit is the most important attribute of a polymer. Polymer terminology is based on the type of monomer the polymer is comprised of. Polymers containing only one type of repeat unit are called homo-polymers, and those containing many repeat units are known as co-polymers. Some complicated polymers like DNA are composed of large variety of sub-units.


References: Journal Science, University of Massachusetts, Amherst, North Carolina State University, SAE International, Integral Technologies and Wikipedia.