Polymers Polymers Alcaligenes eutrophus is a bacterial species that naturally produces polyhydroxyalkanoates (PHA). PHA's are a broad type of biodegradable polymers that can be used for biodegradable plastics. Alcaligenes eutrophus specifically produces polyhydroxybutyrate (PHB), which it uses for storing carbon when in an environment with abundant carbon, but limited essential nutrients such as nitrogen or phosphorus. The gene for PHB production has been cloned and engeneered into plants. ...more on Wikipedia about "Alcaligenes eutrophus"
Alternating copolymers are polymers which have properities intermediate to those of the corresponding homopolymers A and B. ...more on Wikipedia about "Alternating polymer"
Amorphous Poly-alpha-olefins (APAO) are produced by (co-) polymerisation of α-olefins (e.g. ethylene, propene, 1-butene) with Ziegler-Natta catalysts. The (co-)polymers have an amorphous structure which makes them useful for the production of hot melt adhesives. ...more on Wikipedia about "APAO"
Azobisisobutyronitrile, also azobisisobutylonitrile, is a toxic white crystalline compound often used as a foamer in plastics and rubber. It is commonly known as AIBN, it decomposes by the elimination of a molecule of nitrogen gas to form two 2-cyanoprop-2-yl radicals:
...more on Wikipedia about "Azobisisobutylonitrile"
In polymer chemistry, branching occurs by the replacement of a substituent, e.g, a hydrogen atom, on a monomer subunit, by another covalently bonded chain of that polymer; or, in the case of a graft copolymer, by a chain of another type. In crosslinking rubber by vulcanization, short sulfur branches link polyisoprene chains (or a synthetic variant) into a multipy-branched thermosetting elastomer. Rubber can also be so completely vulcanized that it becomes a rigid solid, so hard it can be used as the bit in a smoking pipe. Polycarbonate chains can be crosslinked to form the hardest, most impact-resistant thermosetting plastic, used in safety glasses. ** ...more on Wikipedia about "Branching (chemistry)"
A Bucky gel actuator is a plastic actuator based on a electroactive polymer system. The actuator is a polymer-supported layer of polyelectrolyte material consisting of an ionic liquid sandwiched between two electrode layers consisting of a gel of ionic liquid containing single wall carbon nanotubes. The name refers to bucky balls. [1] ...more on Wikipedia about "Bucky gel actuator"
Butyl rubber is a synthetic rubber, a random copolymer of about 98% of isobutylene with about 2% of isoprene. It has excellent impermeability, and the long polyisobutylene segments of its polymer chains give it good flex properties. ...more on Wikipedia about "Butyl rubber"
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Condensation polymers are any class of polymers formed through a condensation reaction, releasing (or condensing) a small molecule by-product such as water or methanol, as opposed to addition polymers which involve the reaction of unsaturated monomers. Types of condensation polymers include polyamides, polyacetals and polyesters. ...more on Wikipedia about "Condensation polymer"
Conductive polymers are organic polymer semiconductors, or organic semiconductors. ...more on Wikipedia about "Conductive polymers"
In chemistry, copolymerization is the process of using more than one monomer in the production of a polymer, resulting in a product with properties different to the homopolymer of either monomer. The resulting product may be a random copolymer, an alternating copolymer, or a block copolymer. In the copolymerization between two monomers, M1 and M2, the following reactions may occur: ...more on Wikipedia about "Copolymerization"
In chemistry, a dimer refers to a molecule composed of two similar subunits or monomers linked together. It is a special case of a polymer. It can refer to halide chemistry, involving halogen bonding. Its more common usage refers to dimers as certain types of sugar: sucrose, for example, is a dimer of a glucose molecule and a fructose molecule. ...more on Wikipedia about "Dimer"
The term elastomer is often used interchangeably with the term rubber, and is preferred when referring to vulcanisates. They are amorphous polymers existing above their glass transition temperature, so that considerable segmental motion is possible. At ambient temperatures rubbers are thus relatively soft ( E~3MPa) and deformable. Their primary uses are for seals, adhesives and molded flexible parts. ...more on Wikipedia about "Elastomer"
Electroactive Polymers or EAPs are polymers whose shape is modified when a voltage is applied to them. ...more on Wikipedia about "Electroactive polymers"
A graft copolymer has polymer chains of one kind growing out of the sides of polymer chains with a different chemical composition. ...more on Wikipedia about "Graft copolymer"
A heteropolymer, also called a copolymer, is a polymer formed when two (or more) different types of monomer are linked in the same polymer chain, as opposed to a homopolymer where only one monomer is used. If exactly three monomers are used, it is called a terpolymer. ...more on Wikipedia about "Heteropolymer"
Hydrogel is a network of polymer chains that are water-soluble, sometimes found as a colloidal gel in which water is the dispersion medium. Hydrogels are superabsorbent (they can contain over 99% water) natural or synthetic polymers. ...more on Wikipedia about "Hydrogel"
An initiator can refer to ...more on Wikipedia about "Initiator"
An ionomer is a polyelectrolyte that comprises copolymers containing both electrically neutral repeating units and a fraction of ionic units (usually no more than 15%). Ionomers have unique physical properties due to ionic interaction in discrete regions ofthe material. ...more on Wikipedia about "Ionomer"
In polymer chemistry, living polymerization is a special form of addition polymerization where the ability of a growing polymer chain to terminate has been removed . This can be accomplished in a variety of ways. Chain termination and chain transfer reactions are absent and the rate of chain initiation is also much larger than the rate of chain propagation. The result is that the polymer chains grow at a more constant rate than seen in traditional chain polymerization and their lengths remain very similar (i.e. they have a very low polydispersity index). Living polymerization is a popular method for synthesizing block copolymers since the polymer can be synthesized in stages, each stage containing a different monomer. Additional advantages are predetermined molar mass and control over end-groups. Living polymerization in the literature is often called "living" polymerization or controlled polymerization. Living polymerization was first described by M. Szwarc in 1956 in the anionic polymerization of styrene with a alkali metal / naphthalene system in THF. He found that after addition of monomer to the initiator system that the increase in viscosity would eventually cease but that after addition of a new amount of monomer after some time the viscosity would start to increase again . ...more on Wikipedia about "Living polymerization"
Long fiber thermoplastics (LFT) are one of the fastest growing materials in the polymer composites industry. Their advantages of high specific tensile properties and recyclability have enabled them to replace metals and thermoset composites in several areas of daily life. Besides with the independence of choosing the reinforcement from a wide range of fibers and the matrix from a wide range of thermoplastics polymer in the LFTs, its property can be changed according to customer needs. It is the material that has already been deep inside the ocean and has been there in outer space too. ...more on Wikipedia about "Long fiber thermoplastic"
Merrifield Resin is a polystyrene resin based on a copolymer of styrene and chloromethylstyrene. In addition this polymer is also cross-linked with divinylbenzene present in the monomer composition up to 5%. Merrifield resin is named after its inventor, Robert Bruce Merrifield, and used in Solid-phase synthesis. ...more on Wikipedia about "Merrifield resin"
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Micro-encapsulation is a process in which tiny particles or droplets are surrounded by a coating to give small capsules with many useful properties. In its simplest form, a microcapsule is a small sphere with a uniform wall around it. The material inside the microcapsule is referred to as the core, internal phase, or fill, whereas the wall is sometimes called a shell, coating, or membrane. Most microcapsules have diameters between a few micrometers and a few millimeters. ...more on Wikipedia about "Micro-encapsulation"
The Molar mass distribution in a polymer describes the relationship between a polymer fraction and the molar mass of that polymer fraction. In linear polymers the individual polymer chains rarely have the exact same degree of polymerization and there is always a distribution around an average value. ...more on Wikipedia about "Molar mass distribution"
In chemistry, molecular imprinting is a technique to create template-shaped cavities in polymer matrices with memory of the template molecules. This technique is based on the system used by enzymes for substrate recognition, which is called the "lock and key" model. The active binding site of an enzyme has a unique geometric structure that is particularly suitable for a substrate. A substrate that has a corresponding shape to the site is recognized by selectively binding to the enzyme, while an incorrectly shaped molecule that does not fit the binding site is not recognized. ...more on Wikipedia about "Molecular imprinting"
Nucleation is the onset of a phase transition in a small but stable region. For example, bubbles of carbon dioxide nucleate shortly after the pressure is released from a container of carbonated liquid. Nucleation often occurs more easily at a pre-existing interface (heterogeneous nucleation), as happens on boiling chips and string used to make rock candy. Nucleation generally occurs with much more difficulty in the interior of a uniform substance, by a process called homogeneous nucleation. It is key to understanding the thermal processing of polymers, alloys, and some ceramics. It is also important in meteorology (see cloud seeding). ...more on Wikipedia about "Nucleation" www.shortopedia.com - Xtending Info.
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