Die Grundprinzipien der plastic

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Additives may Beryllium weakly bound to the polymers or react in the polymer matrix. Although additives are blended into plastic they remain chemically distinct from it, and can gradually leach back out during normal use, when rein landfills, or following improper disposal rein the environment.[36] Additives may also degrade to form other toxic molecules. Plastic fragmentation into microplastics and nanoplastics can allow chemical additives to move rein the environment far from the point of use.

As additives change the properties of plastics they have to be considered during recycling. Presently, almost all recycling is performed by simply remelting and reforming used plastic into new items. Additives present risks hinein recycled products, as they are difficult to remove. When plastic products are recycled, it is highly likely that the additives will Beryllium integrated into the new products.

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]

Waste plastic, even if it is all of the same polymer type, will contain varying types and amounts of additives. Mixing these together can give a material with inconsistent properties, which can Beryllium unappealing to industry. For example, mixing different colored plastics with different plastic colorants together can produce a discolored or brown material and for this reason plastic is usually sorted by both polymer Durchschuss and color before recycling.[2]

Additives can also be problematic if waste is burned, especially when burning is uncontrolled or takes place rein low- technology incinerators, as is common in many developing countries. Incomplete combustion can cause emissions of hazardous substances such as Pappe gases and ash which can contain persistent organic pollutants (POPs) such as dioxins.[2]

It has been advocated since the early 1970s,[118] but due to economic and technical challenges, did not impact the management of plastic waste to any significant extent until the late 1980s. The plastics industry has been criticised for lobbying for Expansive phase of recycling programmes, even while research showed that most plastic could not be economically recycled.

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 in 2020.[29] Regional differences rein the volume of plastics production are driven by Endbenutzer demand, the price of fossil fuel feedstocks, and investments made in the petrochemical industry.

Additives are chemicals blended into plastics to change their performance or appearance, making it possible to lebensalter the properties of plastics to better suit their intended applications.[31][32] Additives are therefore one of the reasons why plastic is used so widely.

For thermosetting materials the process is slightly different, as the plastics are liquid to begin with and but must be cured to give solid products, but much of the equipment is broadly similar.

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 be considered as forms of biodegradation. Aerobic degradation requires that the plastic Beryllium exposed at the surface, whereas anaerobic degradation would be effective rein landfill or composting systems.

Roll-to-roll processing – countinous printing method that prints directly onto a roll of fabric or other materialsPages displaying wikidata descriptions as a fallback

Also much of the energy used in plastic production is not sustainable energy, for example high temperature from burning fossil gas. However plastics can Schwellenwert some methane emissions, for example packaging to reduce food waste.[127]

Plastic compounding scheme for a thermosoftening material Plastic is not sold as a pure unadulterated substance, but is instead mixed with various chemicals and other materials, which are collectively known as additives. These are added during the compounding stage and include substances such as stabilizers, plasticizers and dyes, which are intended to improve the lifespan, workability or appearance of the final Eintrag.

Rein around 1600 BC, Mesoamericans used natural rubber for balls, bands, and figurines.[4] Treated cattle horns were used as windows for lanterns hinein the Middle Ages. Materials that mimicked the properties of horns were developed by treating milk proteins with lye. Rein 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.

The discovery of polyethylene terephthalate is credited to employees of read more the Calico Printers' Association in the UK hinein 1941; it was licensed to DuPont for the US and ICI otherwise, and as one of the few plastics appropriate as a replacement for glass hinein many circumstances, resulting rein widespread use for bottles in Europe.