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The term plastics covers a range of synthetic or semi-synthetic organic condensation or polymerization products that can be molded or extruded into objects or films or fibers. Their name is derived from the fact that in their semi-liquid state they are malleable, or have the property of plasticity. Plastics vary immensely in heat tolerance, hardness, and resiliency. Combined with this adaptability, the general uniformity of composition and lightness of plastics ensures their use in almost all industrial applications today.

Plastic may also refer to any material charicterized by deformation or failure under shear stress- see Plasticity (physics) and ductile.

1 Natural polymers

Plastics are polymers: long-chain of carbon- or silicon-based molecules. These chains are made up of repeating fundamental molecular elements, or "monomers".

People have been using artificial organic polymers for centuries in the form of waxes and shellacs. A plant polymer named " cellulose" provides the structural strength for natural fiber s and ropes, and by the early 19th century natural rubber, tapped from rubber trees, was in widespread use.

Eventually, inventors learned to improve the properties of natural polymers. Natural rubber was sensitive to temperature, becoming sticky and smelly in hot weather and brittle in cold weather. In 1834, two inventors, Friedrich Ludersdorf of Germany and Nathaniel Hayward of the US, independently discovered that adding sulfur to raw rubber helped prevent the material from becoming sticky.

In 1839Events January 9 The French Academy of Sciences announces the Daguerreotype photography process. January 19 British East India Company captures Aden January 20 In the Battle of Yungay, Chile defeats a Peruvian and Bolivian alliance. February 24 William Ot, the American inventor Charles GoodyearScientific American article Charles Goodyear ( December 29, 1800 July 1, 1860) was the inventor of vulcanized rubber. He died in deep debt and is interred at Grove Street Cemetery, New Haven, Connecticut. Neither Goodyear nor his family was ever connected was experimenting with the sulfur treatment of natural rubber when, according to legend, he dropped a piece of sulfur-treated rubber on a stove. The rubber seemed to have improved properties, and Goodyear followed up with further experiments, and developed a process known as " vulcanizationVulcanization is the process of cross-linking elastomer molecules to make the bulk material harder, less soluble and more durable. It is also called curing. It is the heart of the art and science of rubber compounding. Vulcanization is a chemical process" that involved cooking the rubber with sulfur. Compared to untreated natural rubber, Goodyear's "vulcanized rubber" was stronger, more resistant to abrasion, more elastic, much less sensitive to temperature, impermeable to gases, and highly resistant to chemicals and electric current.

Vulcanization remains an important industrial process for the manufacture of rubber in both natural and artificial forms. Natural rubber is composed of an organic polymer named " isopreneIsoprene is the chemical 2-methyl-1,3-butadiene. It is a common structural motif in biological systems. The terpenes (for example, the carotenes are tetraterpenes) are derived from isoprene, as are the terpenoids and coenzyme Q. Also derived from isoprene". Vulcanization creates sulfur bonds that link separate isoprene polymers together, improving the material's structural integrity and its other properties.



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