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Young's modulus is defined as the ratio of the stress (force per unit area) applied to the object and the resulting axial strain (displacement or deformation) in the linear elastic region of the material. Although Young's modulus is named after the 19th-century British scientist Thomas Young, the concept was developed in 1727 by Leonhard Euler.
Polychlorinated biphenyls ( PCBs) are highly carcinogenic chemical compounds, formerly used in industrial and consumer products, whose production was banned in the United States by the Toxic Substances Control Act in 1976 and internationally by the Stockholm Convention on Persistent Organic Pollutants in 2001.
- Light yellow or colorless, thick, oily liquids
- UN 2315
- Variable
- Uses
- History
- Physical Properties
- Copolymers
- Production
- Environmental Concerns
- Safety
- Bottle Processing Equipment
- Polyester Recycling
- See Also
Textiles
Polyester fibres are widely used in the textile industry. The invention of the polyester fibre is attributed to J. R. Whinfield. It was first commercialized in the 1940s by ICI, under the brand 'Terylene'. Subsequently E. I. DuPontlaunched the brand 'Dacron'. As of 2022, there are many brands around the world, mostly Asian. Polyester fibres are used in fashion apparel often blended with cotton, as heat insulation layers in thermal wear, sportswear and workwear and automotive upholstery.
Rigid packaging
Plastic bottles made from PET are widely used for soft drinks, both still and sparkling. For beverages that are degraded by oxygen, such as beer, a multilayer structure is used. PET sandwiches an additional polyvinyl alcohol (PVOH) or polyamide(PA) layer to further reduce its oxygen permeability. Non-oriented PET sheet can be thermoformed to make packaging trays and blister packs. Crystallizable PET withstands freezing and oven baking temperatures.: 1378 Both amorphous PET and BoPET are trans...
Flexible packaging
Biaxially oriented PET (BOPET) film (often known by one of its trade names, "Mylar") can be aluminized by evaporating a thin film of metal onto it to reduce its permeability, and to make it reflective and opaque (MPET). These properties are useful in many applications, including flexible food packaging and thermal insulation (such as space blankets).
PET was patented in 1941 by John Rex Whinfield, James Tennant Dickson and their employer the Calico Printers' Association of Manchester, England. E. I. DuPont de Nemours in Delaware, United States, first used the trademark Mylar in June 1951 and received registration of it in 1952.It is still the best-known name used for polyester film. The current...
PET in its most stable state is a colorless, semi-crystalline resin. However it is intrinsically slow to crystallize compared to other semicrystalline polymers. Depending on processing conditions it can be formed into either amorphous or crystalline articles. Its amenability to drawing makes PET useful in fibre and film applications. Like most arom...
PET is copolymerized with other diols or diacids to optimize the properties for particular applications. For example, cyclohexanedimethanol (CHDM) can be added to the polymer backbone in place of ethylene glycol. Since this building block is much larger (six additional carbon atoms) than the ethylene glycol unit it replaces, it does not fit in with...
Polyethylene terephthalate is produced from ethylene glycol (usually referred to in the trade as "MEG", for monoethylene glycol) and dimethyl terephthalate (DMT) (C6H4(CO2CH3)2) but mostly terephthalic acid (known in the trade as "PTA", for purified terephthalic acid). As of 2022, ethylene glycol is made from ethene found in natural gas, while tere...
Resource depletion
Compared to the use of petroleum as fuel, however, the amount of crude oil processed into PET is very small. The total production capacity of PET is around 30 million tons, compared to 4.2 billion tons of crude oil production,thus around 0.7% of crude oil is processed into PET.
Commentary published in Environmental Health Perspectives in April 2010 suggested that PET might yield endocrine disruptors under conditions of common use and recommended research on this topic. Proposed mechanisms include leaching of phthalates as well as leaching of antimony.An article published in Journal of Environmental Monitoring in April 201...
There are two basic molding methods for PET bottles, one-step and two-step. In two-step molding, two separate machines are used. The first machine injection molds the preform, which resembles a test tube, with the bottle-cap threads already molded into place. The body of the tube is significantly thicker, as it will be inflated into its final shape...
Worldwide, 480 billion plastic drinking bottles were made in 2016 (and less than half were recycled). While most thermoplastics can, in principle, be recycled, PET bottle recycling is more practical than many other plastic applications because of the high value of the resin and the almost exclusive use of PET for widely used water and carbonated so...
Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene. Polypropylene belongs to the group of polyolefins and is partially crystalline and non-polar. Its properties are similar to polyethylene, but it is slightly ...
The Great Wall of China ( traditional Chinese: 萬里長城; simplified Chinese: 万里长城; pinyin: Wànlǐ Chángchéng, literally "ten thousand li long wall") is a series of fortifications that were built across the historical northern borders of ancient Chinese states and Imperial China as protection against various nomadic groups from ...
After the Deluge is an oil painting by English artist George Frederic Watts. Completed in 1891, it shows a scene from the story of Noah's Flood, in which Noah opens the window of his Ark to see that after 40 days the rain has stopped. The Symbolist painting is a stylised seascape, dominated by a bright sunburst breaking through clouds.
Polyethylene glycol (PEG; / ˌ p ɒ l i ˈ ɛ θ əl ˌ iː n ˈ ɡ l aɪ ˌ k ɒ l,-ˈ ɛ θ ɪ l-,-ˌ k ɔː l /) is a polyether compound derived from petroleum with many applications, from industrial manufacturing to medicine.PEG is also known as polyethylene oxide (PEO) or polyoxyethylene (POE), depending on its molecular weight. ...
