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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 Beryllium exposed at the surface, whereas anaerobic degradation would Beryllium effective rein landfill or composting systems.
However they are still routinely found rein some plastic packaging including food packaging. The use of the additive bisphenol A (BPA) rein plastic baby bottles is banned rein many parts of the world, but is not restricted hinein 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 parte of the chain that is on the main path, linking together a large number of repeat units.
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 hinein the environment for long periods, become widely distributed geographically, accumulate in the fatty tissue of humans and wildlife, and have harmful impacts on human health or on the environment.[2]
Prior to the Montreal Protocol, CFCs had been commonly used hinein the manufacture of the plastic polystyrene, the production of which had contributed to depletion of the ozone layer.
Plastics engineering – Engineering field studying polymer materialsPages click here displaying short descriptions of redirect targets
Historically, Europe and North America have dominated global plastics production. However, since 2010 Asia has emerged as a significant producer, with China accounting for 31% of total plastic resin production rein 2020.[29] Regional differences in the volume of plastics production are driven by Endbenutzer demand, the price of fossil fuel feedstocks, and investments made rein the petrochemical industry.
Plasticity also has a technical definition hinein materials science outside the scope of this article referring to the non-reversible change rein form of solid substances.
Plastics typically are made through human industrial systems. Most modern plastics are derived from fossil fuel-based chemicals like natural gas or petroleum; however, recent industrial methods use variants made from renewable materials, such as corn or cotton derivatives.[1]
Welche person sind die Viehtreiber für die immer fort steigende Produktion von Plaste außerdem welche Lösungsansätze sind sinnvoll ansonsten realistisch?
Hazardous molds have been found aboard space stations that degrade rubber into a digestible form.[97]
There are differing estimates of how much plastic waste has been produced in the last century. By one estimate, one billion tons of plastic waste have been discarded since the 1950s.
Chemical structures and uses of some common plastics Around 70% of global production is concentrated in six major polymer types, the so-called commodity plastics. Unlike most other plastics these can often be identified by their resin identification code (RIC):
The compounding of thermosetting plastic is relatively straightforward; as it remains liquid until it is cured into its final form. For thermosoftening materials, which are used to make the majority of products, it is necessary to melt the plastic rein order to Potpourri-rein the additives.
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 amber.