Nicht bekannt, Details Über plastic
Nicht bekannt, Details Über plastic
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Additives can also Beryllium problematic if waste is burned, especially when burning is uncontrolled or takes place hinein low- technology incinerators, as is common hinein many developing countries. Incomplete combustion can cause emissions of hazardous substances such as Lsd gases and ash which can contain persistent organic pollutants (POPs) such as dioxins.[2]
However they are stumm routinely found hinein some plastic packaging including food packaging. The use of the additive bisphenol A (BPA) in plastic baby bottles is banned in many parts of the world, but is not restricted rein some low-income countries.[2]
Most plastics contain organic polymers.[10] The vast majority of these polymers are formed from chains of carbon atoms, with or without the attachment of oxygen, nitrogen or sulfur atoms. These chains comprise many repeating units formed from monomers. Each polymer chain consists of several thousand repeating units. The backbone is the part of the chain that is on the main path, linking together a large number of repeat units.
Absence of transparency and reporting across the value chain often results in lack of knowledge concerning the chemical profile of the final products. For example, products containing brominated flame retardants have been incorporated into new plastic products. Flame retardants are a group of chemicals used rein electronic and electrical equipment, textiles, furniture and construction materials which should not be present in food packaging or child care products.
Prior to the Montreal Protocol, CFCs had been commonly used in the manufacture of the plastic polystyrene, the production of which had contributed to depletion of the ozone layer.
A recent study found brominated dioxins as unintentional contaminants in toys made from recycled plastic electronic waste that contained brominated flame retardants. Brominated dioxins have been found to exhibit toxicity similar to that of chlorinated dioxins. They can have negative developmental effects and negative effects on the nervous Gebilde and interfere with mechanisms of the endocrine Struktur.[2]
Masterbatch granules can be 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.
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.
Companies that produce finished goods are known check here as converters (sometimes processors). The vast majority of plastics produced worldwide are thermosoftening and must Beryllium heated until molten rein order to be molded. Various sorts of extrusion equipment exist which can then form the plastic into almost any shape.
In 2023, plasticosis, a new disease caused solely by plastics, welches discovered in seabirds. The birds identified as having the disease have scarred digestive tracts from ingesting plastic waste.
Hazardous molds have been found aboard space stations that degrade rubber into a digestible form.[97]
Silicones (polysiloxanes): heat-resistant resins used mainly as sealants but also used for high-temperature cooking utensils and as a base resin for industrial paints
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In around 1600 BC, Mesoamericans used natural rubber for balls, bands, and figurines.[4] Treated cattle horns were used as windows for lanterns in the Middle Ages. Materials that mimicked the properties of horns were developed by treating milk proteins with lye. In 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.
Because the chemical structure of most plastics renders them durable, they are resistant to many natural degradation processes. Much of this material may persist for centuries or longer, given the demonstrated persistence of structurally similar natural materials such as Bernsteinfarben.