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Copolymerization is used to modify the properties of manufactured plastics to meet specific needs, for example to reduce crystallinity, modify glass transition temperature, control wetting properties or to improve solubility. [43] It is a way of improving mechanical properties, in a technique known as rubber toughening. Elastomeric phases ...
Coordination polymerization started in the 1950s with heterogeneous Ziegler–Natta catalysts based on titanium tetrachloride and organoaluminium co-catalysts. The mixing of TiCl 4 with trialkylaluminium complexes produces Ti (III)-containing solids that catalyze the polymerization of ethene and propene. The nature of the catalytic center has ...
Graft polymers have been synthesized for many decades and are especially used as impact resistant materials, thermoplastic elastomers, compatibilizers, or emulsifiers for the preparation of stable blends or alloys. One of the better-known examples of a graft polymer is a component used in high impact polystyrene, consisting of a polystyrene ...
e. In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. [1][2][3] There are many forms of polymerization [4] and different systems exist to categorize them.
It was proposed by Frank R. Mayo and Frederick M. Lewis. [1] The equation considers a monomer mix of two components and and the four different reactions that can take place at the reactive chain end terminating in either monomer ( and ) with their reaction rate constants : The reactivity ratio for each propagating chain end is defined as the ...
In polymer chemistry, emulsion polymerization is a type of radical polymerization that usually starts with an emulsion incorporating water, monomers, and surfactants. The most common type of emulsion polymerization is an oil-in-water emulsion, in which droplets of monomer (the oil) are emulsified (with surfactants) in a continuous phase of water.
Gradient copolymer. In polymer chemistry, gradient copolymers are copolymers in which the change in monomer composition is gradual from predominantly one species to predominantly the other, [1] unlike with block copolymers, which have an abrupt change in composition, [2] [3] and random copolymers, which have no continuous change in composition ...
Ethylene vinyl alcohol (EVOH) is a formal copolymer of ethylene and vinyl alcohol. Because the latter monomer mainly exists as its tautomer acetaldehyde, the copolymer is prepared by polymerization of ethylene and vinyl acetate to give the ethylene vinyl acetate (EVA) copolymer followed by hydrolysis. EVOH copolymer is defined by the mole ...