Plastic is the general common term for a wide range of synthetic or semisynthetic organic Organic Chemistry is a discipline within chemistry that involves the scientific study of the structure, properties, composition, reactions, and preparation of hydrocarbons and their derivatives. These compounds may contain any number of other elements, including hydrogen, nitrogen, oxygen, the halogens as well as phosphorus, silicon and sulfur amorphous solid An "amorphous solid" is a solid in which there is no long-range order of the positions of the atoms. . Most classes of solid materials can be found or prepared in an amorphous form. For instance, common window glass is an amorphous solid, many polymers (such as polystyrene) are amorphous, and even foods such as cotton candy are amorphous[1] materials used in the manufacture of industrial products. Plastics are typically polymers A polymer is a large molecule composed of repeating structural units typically connected by covalent chemical bonds. While polymer in popular usage suggests plastic, the term actually refers to a large class of natural and synthetic materials with a variety of properties of high molecular mass The molecular mass of a substance, frequently referred to by the older term molecular weight and abbreviated as MW, is the mass of one molecule of that substance, relative to the unified atomic mass unit u (equal to 1/12 the mass of one isotope of carbon-12). This is distinct from the relative molecular mass of a molecule, which is the ratio of, and may contain other substances to improve performance and/or reduce costs.
The word is derived from the Greek Greek , an independent branch of the Indo-European family of languages, is the language of the Greeks. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. In its ancient form, it is the language of classical ancient Greek literature and the New Testament of πλαστικός (plastikos) meaning fit for molding, and πλαστός (plastos) meaning molded.[2][3] It refers to their malleability, or plasticity In physics and materials science, plasticity describes the deformation of a material undergoing non-reversible changes of shape in response to applied forces. For example, a solid piece of metal or plastic being bent or pounded into a new shape displays plasticity as permanent changes occur within the material itself. By contrast, a permanent during manufacture, that allows them to be cast Casting is a manufacturing process by which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process. Casting materials are usually metals or various cold, pressed Death by crushing or pressing is a method of execution that has a long history during which the techniques used varied greatly from place to place. This form of execution is no longer sanctioned by any governing body, or extruded Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed or drawn through a die of the desired cross-section. The two main advantages of this process over other manufacturing processes are its ability to create very complex cross-sections and work materials that are brittle, because the material only into a variety of shapes—such as films Artificial membrane also known as synthetic membrane is a syntheticly created membrane which is usually intended for separation purposes in laboratory or in industry. Synthetic membranes have been successfully used for small and large-scale industrial processes since the middle of twentieth century. A wide variety of synthetic membranes is known, fibers Synthetic fibers are the result of extensive research by scientists to improve upon naturally occurring animal and plant fibers. In general, synthetic fibers are created by forcing, usually through extrusion, fiber forming materials through holes into the air, forming a thread. Before synthetic fibers were developed, artificially manufactured, plates, tubes, bottles, boxes, and much more.
The common word plastic should not be confused with the technical adjective plastic, which is applied to any material which undergoes a permanent change of shape (plastic deformation In physics and materials science, plasticity describes the deformation of a material undergoing non-reversible changes of shape in response to applied forces. For example, a solid piece of metal or plastic being bent or pounded into a new shape displays plasticity as permanent changes occur within the material itself. By contrast, a permanent) when strained beyond a certain point. Aluminium, for instance, is plastic in this sense, but not a plastic in the common sense; in contrast, in their finished forms, some plastics will break before deforming and therefore are not plastic in the technical sense.
There are two types of plastics: thermoplastics Thermoplastics are elastic and flexible above a glass transition temperature Tg, specific for each one—the midpoint of a temperature range in contrast to the sharp melting point of a pure crystalline substance like water. Below a second, higher melting temperature, Tm, also the midpoint of a range, most thermoplastics have crystalline regions and thermosetting polymers A thermosetting plastic, also known as a thermoset, is polymer material that irreversibly cures. The cure may be done through heat (generally above 200 °C ), through a chemical reaction (two-part epoxy, for example), or irradiation such as electron beam processing. Thermoplastics will soften and melt if enough heat is applied; examples are polyethylene Polyethylene or polythene (IUPAC name polyethene or poly) is the most widely used plastic, with an annual production of approximately 80 million metric tons. Its primary use is within packaging (notably the plastic shopping bag), polystyrene Polystyrene (IUPAC Poly(1-phenylethane-1,2-diyl)), sometimes abbreviated PS, is an aromatic polymer made from the aromatic monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum by the chemical industry. Polystyrene is one of the most widely used kinds of plastic, polyvinyl chloride Polyvinyl chloride, (IUPAC Poly) commonly abbreviated PVC, is a thermoplastic polymer. It is a vinyl polymer constructed of repeating vinyl groups (ethenyls) having one of their hydrogens replaced with a chloride group and polytetrafluoroethylene In chemistry, polytetrafluoroethylene is a synthetic fluoropolymer of tetrafluoroethylene which finds numerous applications. PTFE is most well known by the DuPont brand name Teflon (PTFE)[4]. Thermosets can melt and take shape once; after they have solidified, they stay solid.
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The Plastic Surgery Channel
Nose jobs may be unnecessary for patients suffering from a deviated septum, thanks to new innovations in plastic surgery. Innovations in surgery may ...
