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Plastics are amazingly versatile materials, and their usage in all manner of objects is only increasing. Virtually everything you own is at least partially composed of plastic, and that’s usually a very good thing. Plastic is light, inexpensive, and can be molded in any shape. However, it’s not always the strongest material. Many smartphone owners know the sorrow of dropping a phone and finding the fall cracked or chipped the casing. A new type of plastic developed at Duke University could change all that. This material actually gets stronger when it is stressed.
When the polymer chains are tugged or experience shock, they tear on one side. Other plastic polymers would not be so uniformly damaged, leading to structural failure. However, this is only the beginning of the transformation. The shearing force breaks the triangle into a longer chain, which also frees up bonding sites at the bromine locations for a second molecule to come in.
High shear stresses are known to trigger destructive bond-scission reactions in polymers. Recent work has shown that the same shear forces can be used to accelerate non-destructive reactions in mechanophores along polymer backbones, and it is demonstrated here that such mechanochemical reactions can be used to strengthen a polymer subjected to otherwise destructive shear forces. Polybutadiene was functionalized with dibromocyclopropane mechanophores, whose mechanical activation generates allylic bromides that are crosslinked in situ by nucleophilic substitution reactions with carboxylates. The crosslinking is activated efficiently by shear forces both in solvated systems and in bulk materials, and the resulting covalent polymer networks possess moduli that are orders-of-magnitude greater than those of the unactivated polymers. These molecular-level responses and their impact on polymer properties have implications for the design of materials that, like biological materials, actively remodel locally as a function of their physical environment.
When measured on the microscopic scale through a technique called nanoindentation, scientists found that the hardness increased by 200 times after the extrusion process. It even works when the plastic is dissolved in a solution.
Originally posted by atsmediapro
I double tapped the return key when entering the title and it submitted the thread before I had any content
Acute exposure results in irritation of the mucous membranes, Higher levels can result in neurological effects such as blurred vision, fatigue, headache and vertigo. Exposure to the skin can lead to frostbite.
Long-term exposure has been associated with cardiovascular disease, there is a consistent association with leukemia, and weaker association with other cancers.
1,3 Butadiene is listed as a known carcinogen by the Agency for Toxic Substances Disease Registry and the US EPA. The American Conference of Governmental Industrial Hygienists (ACGIH) lists the chemical as a suspected carcinogen. The Natural Resource Defense Council (NRDC) lists some disease clusters that are suspected to be associated with this chemical.
1,3-Butadiene is also a suspected human teratogen. Prolonged and excessive exposure can affect many areas in the human body; blood, brain, eye, heart, kidney, lung, nose and throat have all been shown to react to the presence of excessive 1,3-Butadiene.