Alles über plastic surgery
Alles über plastic surgery
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Plastics engineering – Engineering field studying polymer materialsPages displaying short descriptions of redirect targets
Rein some cases, this can involve mixing different types of plastic together to form a polymer blend, such as high impact polystyrene. Large companies may do their own compounding prior to production, but some producers have it done by a third party. Companies that specialize rein this work are known as Compounders.
Rein around 1600 BC, Mesoamericans used natural rubber for balls, bands, and figurines.[4] Treated cattle horns were used as windows for lanterns rein the Middle Ages. Materials that mimicked the properties of horns were developed by treating milk proteins with lye. Hinein the nineteenth century, as chemistry developed during the Industrial Revolution, many materials were reported. The development of plastics accelerated with Charles Goodyear's 1839 discovery of vulcanization to harden natural rubber.
A plastic handle from a kitchen utensil, deformed by heat and partially melted One important classification of plastics is the degree to which the chemical processes used to make them are reversible or not.
Plastics can be brittle, adding some plasticizer makes them more durable, adding lots makes them flexible
A number of additives identified as hazardous to humans and/or the environment are regulated internationally. The Stockholm Convention on Persistent Organic Pollutants (POPs) is a global treaty to protect human health and the environment from chemicals that remain intact in the environment for long periods, become widely distributed geographically, accumulate rein the fatty tissue of humans and wildlife, and have harmful impacts on human health or on the environment.[2]
Biodegradable plastics are plastics that degrade (break down) upon exposure to sunlight or ultra-violet radiation; water or dampness; bacteria; enzymes; or wind abrasion. Attack by insects, such as waxworms and mealworms, can also Beryllium considered as forms of biodegradation. Aerobic degradation requires that the plastic be exposed at the surface, whereas anaerobic degradation would Beryllium effective rein landfill or composting systems.
Quickly burning plastics at very high temperatures breaks down many toxic components, such as dioxins and furans. This approach is widely used rein municipal solid waste incineration. Municipal solid waste incinerators also normally treat the flue gas to decrease pollutants further, which is needed because uncontrolled incineration of plastic produces carcinogenic polychlorinated dibenzo-p-dioxins.
For thermosetting materials the process is slightly different, as the plastics are liquid to begin with and but must Beryllium cured to give solid products, but much of the equipment is broadly similar.
Polycarbonate + acrylonitrile butadiene styrene (PC + ABS): a blend of Parallaxensekunde and ABS that creates a stronger plastic used hinein car interior and exterior parts, and rein mobile phone bodies
Also much of the energy used in plastic production is not sustainable energy, for example high temperature from burning fossil gas. However plastics can Grenzwert some methane emissions, for example packaging to reduce food waste.[127]
A huge number of plastics exist beyond the commodity plastics, with many having exceptional properties.
Microbial communities isolated from soil samples mixed with starch have been shown to be capable more info of degrading polypropylene.[92]
Masterbatch granules can Beryllium mixed with cheaper bulk polymer and will release their additives during processing to give a homogeneous final product. This can Beryllium cheaper than working with a fully compounded material and is particularly common for the introduction of color.
Plastic recycling is low hinein the waste hierarchy, meaning that reduction and reuse are more favourable and long-term solutions for sustainability.