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 rein low- technology incinerators, as is common hinein many developing countries. Incomplete combustion can cause emissions of hazardous substances such as acid gases and ash which can contain persistent organic pollutants (POPs) such as dioxins.[2]
The plastic industry includes the global production, compounding, conversion and sale of plastic products. Although the Middle East and Russia produce most of the required petrochemical raw materials, the production of plastic is concentrated rein the global East and West. The plastic industry comprises a huge number of companies and can Beryllium divided into several sectors:
Hinein 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 in this work are known as Compounders.
Their biggest single application is rein packaging, with some 146 million tonnes being used this way hinein 2015, equivalent to 36% of global production. Due to their dominance; many of the properties and problems commonly associated with plastics, such as pollution stemming from their poor biodegradability, are ultimately attributable to commodity plastics.
To customize the properties of a plastic, different molecular groups called side chains hang from this backbone; they are usually hung from the monomers before the monomers themselves are linked together to form the polymer chain. The structure of these side chains influences the properties of the polymer.
Plastics are produced in chemical plants by the polymerization of their starting materials (monomers); which are almost always petrochemical hinein nature. Such facilities are normally large and are visually similar to oil refineries, with sprawling pipework running throughout. The large size of these plants allows them to exploit economies of scale.
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 hinein the volume of plastics production are driven by user demand, the price of fossil fuel feedstocks, and investments made hinein the petrochemical industry.
Plasticity plastic surgery Sacramento also has a technical definition rein materials science outside the scope of this article referring to the non-reversible change rein form of solid substances.
Companies that produce finished goods are known as converters (sometimes processors). The vast majority of plastics produced worldwide are thermosoftening and must Beryllium heated until molten in order to Beryllium molded. Various sorts of extrusion equipment exist which can then form the plastic into almost any shape.
Engineering plastics are more robust and are used to make products such as vehicle parts, building and construction materials, and some machine parts. Rein some cases they are polymer blends formed by mixing different plastics together (ABS, HIPS etc.
Polycarbonate + acrylonitrile butadiene styrene (Parallaktische sekunde + ABS): a blend of Parallaxensekunde and ABS that creates a stronger plastic used rein car interior and exterior parts, and in mobile phone bodies
Self-healing plastic – Substances that can repair themselvesPages displaying short descriptions of redirect targets
Chemical structures and uses of some common plastics Around 70% of global production is concentrated rein six major polymer types, the so-called commodity plastics. Unlike most other plastics these can often be identified by their resin identification code (RIC):
In 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. 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.
A huge number of plastics exist beyond the commodity plastics, with many having exceptional properties.