Addition polymerization involves the linking together of molecules incorporating double or triple chemical bonds. These unsaturated monomers (the identical molecules which make up the polymers) have extra, internal, bonds which are able to break and link up with other monomers to form the repeating chain. Addition polymerization is involved in the manufacture of polymers such as polyethene, polypropylene and polyvinyl chloride (PVC). A special case of addition pol ...

See also:

Polymerization, Polymerization - Overview, Polymerization - History

Read more here: » Polymerization: Encyclopedia II - Polymerization - Overview

See also:

Polypropylene glycol, Polypropylene glycol - Polymerization, Polypropylene glycol - Properties, Polypropylene glycol - Uses

Read more here: » Polypropylene glycol: Encyclopedia II - Polypropylene glycol - Polymerization

Liquid crystalline polyesters are among the first industrially used liquid crystalline polymers. In general they have extremely good mechanical properties and are extremely heat resistant. For that reason, they can be used as an abradable seal in jet engines. Thermosetting polyester resins are commonly used as casting materials, fiberglass laminating resins, and non-metallic auto-body fillers. In such applications, polymerization and cross-linking are initiated through an exothermic reaction involving an organic peroxide, such as meth ...

See also:

Polyester, Polyester - Common usage and culture, Polyester - Applications, Polyester - Synthesis, Polyester - Azeotrope esterification, Polyester - Alcoholic transesterification, Polyester - Acylation HCl method, Polyester - Acetate method esterification, Polyester - Ring-opening polymerization

Read more here: » Polyester: Encyclopedia II - Polyester - Applications

A vinyl is an organic molecule containing a vinyl, or ethene group. This term is especially used in relationship to vinyl polymers and plastics. The structure is represented as H2C=CHR where R represents a functional group such as a hydrocarbon or halogen. The vinyl group is also at the core of all allyl groups. Polyvinyl chloride - PVC - is made by polymerization of the monomer vinyl chloride (chloroethene) CH2=CHCl Polyvinyl alcohol - PVA - is made by polymerization of the monomer vinyl alco ...

Read more here: » Vinyl: Encyclopedia - Vinyl

Actin is a globular protein that polymerizes helically forming actin filaments (or microfilaments), which like the other two components of the cellular cytoskeleton form a three-dimensional network inside an eukaryotic cell. Actin filaments provide mechanical support for the cell, determine the cell shape, enable cell movements (through lamellipodia, filopodia, or pseudopodia); and participate in certain cell junctions, in cytoplasmic streaming and in contraction of the cell during cytokinesis. In muscle cells they play ...

Including:

Actin - Microfilaments assembly Actin - Organization
Actin - Bundles Actin - Networks
Actin - Genetics Actin - History

Read more here: » Actin: Encyclopedia - Actin

A DNA polymerase is an enzyme that assists in DNA replication. Such enzymes catalyze the polymerization of deoxyribonucleotides alongside a DNA strand, which they "read" and use as a template. The newly polymerized molecule is complementary to the template strand and identical to the template's partner strand. All DNA polymerases synthesize DNA in the 5' to 3' direction. No known DNA polymerase is able to begin a new chain (de novo). They can only add a nucleotide onto a preexisting 3'- OH group. For this reason DNA poly ...

Including:

DNA polymerase - Bacteria DNA polymerase - Eukaryotes

Read more here: » DNA polymerase: Encyclopedia - DNA polymerase

Copper(II) chloride is the higher chloride of copper, with the formula CuCl2. It occurs naturally as the mineral eriochalcite. It is a brown solid which slowly absorbs moisture to form a blue-green dihydrate. It is ionic and highly soluble in water. Chemically it behaves as a weak Lewis acid, and under certain conditions it can act as a mild oxidising agent. It has a crystal structure consisting of polymeric chains of flat CuCl4 units with opposite edges shared. It decomposes to CuCl and Cl2 at ...

Including:

CopperII chloride - Chemical Properties CopperII chloride - Preparation CopperII chloride - Uses CopperII chloride - Precautions CopperII chloride - Suppliers/Manufacturers

Read more here: » CopperII chloride: Encyclopedia - CopperII chloride

Acrylonitrile butadiene styrene, or ABS, (chemical formula ) is a common thermoplastic used to make light, rigid, molded products such as pipes, golf club heads (used for its good shock absorbance), automotive body parts, enclosures, protective head gear, and toys including Lego bricks. It is a copolymer made by polymerizing styrene and acrylonitrile in the presence of polybutadiene. The proportions can vary from 15% to 35% acrylonitrile, 5% to 30% butadiene and 40% to 60% styrene. The result is a long chain of polybutadiene criss-cro ...

Read more here: » Acrylonitrile butadiene styrene: Encyclopedia - Acrylonitrile butadiene styrene

Plastic is a term that covers a range of synthetic or semisynthetic polymerization products. They are composed of organic condensation or addition polymers and may contain other substances to improve performance or economics. There are few natural polymers generally considered to be "plastics". Plastics can be formed into objects or films or fibers. Their name is derived from the fact that many are malleable, having the property of plasticity. Plastics are designed with immense variation in properties such as heat tolerance, hardness, ...

Including:

Plastic - Natural polymers Plastic - Cellulose-based plastics: celluloid and rayon Plastic - Bakelite phenolic Plastic - Polystyrene and PVC Plastic - Nylon Plastic - Synthetic rubber Plastic - Plastics explosion: acrylic polyethylene etc. Plastic - The environment
Plastic - Biodegradable Plastics
Plastic - Price and the future Plastic - Common plastics and their typical uses Plastic - Special purpose plastics

Read more here: » Plastic: Encyclopedia - Plastic

Ultrahard fullerite (C60) is a form of carbon found to be harder than diamond, and which can be used to create even harder materials, such as aggregated diamond nanorods. Specifically, it is a unique version of fullerene with three-dimensional polymer bonds. This should not be confused with P-SWNT fullerite, even though that material is also a polymerized version of fullerene. It has been shown 1 2 that ultrahard fullerite when testing diamond hardness with a scanning force microscope of specific construction can scr ...

Read more here: » Ultrahard fullerite: Encyclopedia - Ultrahard fullerite

The most common general usage of the word polyester is usually in reference into the fiber. Polyester clothing is considered to have a "less natural" feeling to it in comparison to natural fibers. Quite frequently, polyester fibers are spun together with fibers of cotton, producing a cloth with some of the better properties of each. Since before World War II, American middle-class households have had the blessing of having an electricity powered washing machine to assist in the cleaning of clothes. Still a tedious process, many Monday ...

See also:

Polyester, Polyester - Common usage and culture, Polyester - Applications, Polyester - Synthesis, Polyester - Azeotrope esterification, Polyester - Alcoholic transesterification, Polyester - Acylation HCl method, Polyester - Acetate method esterification, Polyester - Ring-opening polymerization

Read more here: » Polyester: Encyclopedia II - Polyester - Common usage and culture

In written chemical equations, free radicals are frequently denoted by a dot placed immediately to the right of the atomic symbol or molecular formula as follows: Cl2 + hν → 2 Cl· Radical reaction mechanisms use ...

See also:

Radical chemistry, Radical chemistry - Depicting radicals in chemical reactions, Radical chemistry - The chemistry of radicals, Radical chemistry - Terminology, Radical chemistry - Formation, Radical chemistry - Persistence and stability, Radical chemistry - Combustion, Radical chemistry - Polymerization, Radical chemistry - Atmospheric radicals, Radical chemistry - Free radicals in biology, Radical chemistry - Diagnostics, Radical chemistry - External link

Read more here: » Radical chemistry: Encyclopedia II - Radical chemistry - Depicting radicals in chemical reactions

Radical chemistry - Terminology. In chemistry free radicals take part in radical addition and radical substitution as reactive intermediates. Reactions involving free radicals are usually divided into three categories: initiation, propagation, and termination. Initiation reactions are those which result in a net increase in the number of free radicals. They may involve the formation of free radicals from stable species as in Reaction 1 above or they may involve reactions o ...

See also:

Radical chemistry, Radical chemistry - Depicting radicals in chemical reactions, Radical chemistry - The chemistry of radicals, Radical chemistry - Terminology, Radical chemistry - Formation, Radical chemistry - Persistence and stability, Radical chemistry - Combustion, Radical chemistry - Polymerization, Radical chemistry - Atmospheric radicals, Radical chemistry - Free radicals in biology, Radical chemistry - Diagnostics, Radical chemistry - External link

Read more here: » Radical chemistry: Encyclopedia II - Radical chemistry - The chemistry of radicals

Free radicals play an important role in a number of biological processes, some of which are necessary for life, such as the intracellular killing of bacteria by neutrophil/ granulocytes. Free radicals have also been implicated in certain cell signalling processes. The two most important oxygen-centered free radicals are superoxide and hydroxyl radical. They are derived from molecular oxygen under reducing conditions. However, because of their reactivity, these same free radicals can participate in unwanted side reactions resulting in cell da ...

See also:

Radical chemistry, Radical chemistry - Depicting radicals in chemical reactions, Radical chemistry - The chemistry of radicals, Radical chemistry - Terminology, Radical chemistry - Formation, Radical chemistry - Persistence and stability, Radical chemistry - Combustion, Radical chemistry - Polymerization, Radical chemistry - Atmospheric radicals, Radical chemistry - Free radicals in biology, Radical chemistry - Diagnostics, Radical chemistry - External link

Read more here: » Radical chemistry: Encyclopedia II - Radical chemistry - Free radicals in biology

Free radicals play an important role in a number of biological processes, some of which are necessary for life, such as the intracellular killing of bacteria by neutrophil granulocytes. Free radicals have also been implicated in certain cell signalling processes. The two most important oxygen-centered free radicals are superoxide and hydroxyl radical. They are derived from molecular oxygen under reducing conditions. However, because of their reactivity, these same free radicals can participate in unwanted side reactions resulting in cell dam ...

See also:

Radical chemistry, Radical chemistry - Depicting radicals in chemical reactions, Radical chemistry - The chemistry of radicals, Radical chemistry - Terminology, Radical chemistry - Formation, Radical chemistry - Persistence and stability, Radical chemistry - Combustion, Radical chemistry - Polymerization, Radical chemistry - Atmospheric radicals, Radical chemistry - Free radicals in biology, Radical chemistry - Diagnostics, Radical chemistry - External link

Read more here: » Radical chemistry: Encyclopedia II - Radical chemistry - Free radicals in biology

In polymer chemistry, a series of condensation reactions take place whereby monomers or monomer chains add to each other to form longer chains. This may also be termed as 'condensation polymerization', 'polycondensation', 'stepgrowth polymerization', or 'stepwise polymerization'. It occurs either as a homopolymerization of an A-B monomer or a polymerization of two co-monomers A-A and B-B. Small molecule condensates are usually liberated, unlike in polyaddition where there is no liberation of small molecules. A high conv ...

See also:

Condensation reaction, Condensation reaction - Mechanism, Condensation reaction - Condensation reactions in polymer chemistry, Condensation reaction - Applications

Read more here: » Condensation reaction: Encyclopedia II - Condensation reaction - Condensation reactions in polymer chemistry

Physical properties of polymers include the degree of polymerization, molar mass distribution, crystallinity, as well as the thermal phase transitions: Tg, glass transition temperature Tm, melting point (for thermoplastics). Polymer - Branching. During the propagation of polymer chains, branching can occur. In free-radical polymerization, this occurs when a chain curls back and bonds to an earlier part of the chain. When this curl breaks, it ...

See also:

Polymer, Polymer - Physical properties of polymers, Polymer - Branching, Polymer - Stereoregularity, Polymer - Constitution of polymers, Polymer - Copolymers, Polymer - Chemical properties of polymers, Polymer - Intermolecular forces, Polymer - Polymer characterization

Read more here: » Polymer: Encyclopedia II - Polymer - Physical properties of polymers

To make polyoxymethylene homopolymer, anhydrous formaldehyde must be generated. The principal method is by reaction of the aqueous formaldehyde with an alcohol to create a hemiformal, dehydration of the hemiformal/water mixture (either by extraction or vacuum distillation) and release of the formaldehyde by heating the hemiformal. The formaldehyde is then polymerized by anionic catalysis and the resulting polymer ...

See also:

Polyoxymethylene, Polyoxymethylene - Synthesis, Polyoxymethylene - External link

Read more here: » Polyoxymethylene: Encyclopedia II - Polyoxymethylene - Synthesis

Macrocycles are generally synthesized from smaller, usually linear, molecules. To create a ring, either an intermolecular reaction, where two or more molecules come together in a reaction to form a ring, or an intramolecular reaction, where one molecule reacts with itself to form a ring, must occur. Because the formation of macrocycles uses the same chemistry that polymerization does, steps need to be taken to prevent polymerization from occurring. Traditionally, this involved high dilution chemistry where large amounts of solvent and ...

See also:

Macrocycle, Macrocycle - Macrocycle Effect, Macrocycle - Synthesis, Macrocycle - Applications, Macrocycle - Historical Uses, Macrocycle - Biological Macrocycles, Macrocycle - Related Molecular Categories, Macrocycle - Related Links

Read more here: » Macrocycle: Encyclopedia II - Macrocycle - Synthesis

A special type of copolymer is called a "block copolymer". Block copolymers are made up of blocks of different polymerized monomers. For example, PS-b-PMMA is short for polystyrene-b-poly(methyl methacrylate) and is made by first polymerizing styrene, and then subsequently polymerizing MMA. This polymer is a "diblock copolymer" because it contains two different chemical blocks. You can also make triblocks, tetrablocks, pentablocks, etc. Diblock copolymers are made using "living polymerization" techniques, such as atom transfer free radical polymerization (ATRP), reversible addition fragmentation chain transfer (RAFT), ...

See also:

Heteropolymer, Heteropolymer - Block Copolymers, Heteropolymer - Types of copolymers

Read more here: » Heteropolymer: Encyclopedia II - Heteropolymer - Block Copolymers