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

While most plastics are produced from petrochemicals, bioplastics are made substantially from renewable plant materials like cellulose and starch.[24] Due both to the finite limits of fossil fuel reserves and to rising levels of greenhouse gases caused primarily by the burning of those fuels, the development of bioplastics is a growing field.

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 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]

Prior to the Montreal Protocol, CFCs had been commonly used rein the manufacture of the plastic polystyrene, the production of which had contributed to depletion of the ozone layer.

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 expansion of recycling programmes, even while research showed that most plastic could not Beryllium economically recycled.

A communication campaign infographic showing that there will Beryllium more plastic in the oceans than fish by 2050

The concentrations of most additives are usually quite low, however high levels can be added to create Masterbatch products. The additives rein these are concentrated but tonlos properly dispersed rein the host resin.

High-performance plastics are usually expensive, with their use limited to specialized applications which make use of their superior properties.

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]

Rein feedstock recycling, waste plastic is converted into its starting chemicals, which can then become fresh plastic. This involves higher energy and capital costs. Alternatively, plastic can Beryllium burned in place of fossil fuels hinein energy recovery facilities, or biochemically converted into other useful chemicals for industry.

There are differing estimates of how much plastic waste has been produced in the belastung century. By one estimate, one billion tons of plastic waste have been discarded since sacramento plastic surgery the 1950s.

Chemical structures and uses of some common plastics Around 70% of global production is concentrated hinein six major polymer types, the so-called commodity plastics. Unlike most other plastics these can often be identified by their resin identification code (RIC):

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.

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.