Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include naturally occurring chemicals, such as in plants and insects, as well as synthetics such as polybutyrate. Natural polyesters and a few synthetic ones are biodegradable, but most synthetic polyesters are not. Synthetic polyesters are used extensively in clothing.
Polyester fibers are sometimes spun together with natural fibers to produce a cloth with blended properties. Cotton-polyester blends can be strong, wrinkle- and tear-resistant, and reduce shrinking. Synthetic fibers using polyester have high water, wind and environmental resistance compared to plant-derived fibers. They are less fire-resistant and can melt when ignited.
Liquid crystalline polyesters are among the first industrially used liquid crystal polymers. They are used for their mechanical properties and heat-resistance. These traits are also important in their application as an abradable seal in jet engines.
Polyesters are one of the most economically important classes of polymers, driven especially by PET, which is counted among the commodity plastics; in 2000 around 30 million tons were produced worldwide. There is great variety of structures and properties in the polyester family, based on the varying nature of the R group (see first figure with blue ester group).
Polyesters occurring in nature include the cutin component of plant cuticles, which consists of omega hydroxy acids and their derivatives, interlinked via ester bonds, forming polyester polymers of indeterminate size. Polyesters are also produced by bees in the genus Colletes, which secrete a cellophane-like polyester lining for their underground brood cells earning them the nickname "polyester bees".
The family of synthetic polyesters comprises
Linear aliphatic high molecular weight polyesters (Mn >10,000) are low-melting (m. p.
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Spandex, Lycra, or elastane is a synthetic fiber known for its exceptional elasticity. It is a polyether-polyurea copolymer that was invented in 1958 by chemist Joseph Shivers at DuPont. The name "spandex", which is an anagram of the word "expands", is the preferred name in North America. In continental Europe, it is referred to by variants of "elastane", including élasthanne (France), Elastan (Germany, Sweden), elastano (Spain), elastam (Italy), and elastaan (Netherlands); and in the UK, Ireland, Portugal, Spain, Latin America, Australia, and New Zealand, it is primarily known as "Lycra".
In organic chemistry, a dicarboxylic acid is an organic compound containing two carboxyl groups (). The general molecular formula for dicarboxylic acids can be written as , where R can be aliphatic or aromatic. In general, dicarboxylic acids show similar chemical behavior and reactivity to monocarboxylic acids. Dicarboxylic acids are used in the preparation of copolymers such as polyamides and polyesters. The most widely used dicarboxylic acid in the industry is adipic acid, which is a precursor in the production of nylon.
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptability, plus a wide range of other properties, such as being lightweight, durable, flexible, and inexpensive to produce, has led to its widespread use. Plastics typically are made through human industrial systems.
This course provides a basic foundation in organic
chemistry and polymer chemistry, including chemical nomenclature of organic compounds and polymers, an understanding of chemical structures, chemical
Know modern methods of polymer synthesis. Understand how parameters, which determine polymer structure and properties, such as molecular weight, molecular weight distribution, topology, microstructure
Ce cours est une introduction au comportement mécanique, à l'élaboration, à la structure et au cycle de vie des grandes classes de matériaux de structure (métaux, polymères, céramiques et composites)
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Polymers play a central role in shaping our world across various fields, but their heavy reliance on petrochemicals poses climate change, environmental and health risks. To address and alleviate these issues, transitioning to sustainable polymers, sourced ...