copolymer

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copolymer:

see polymerpolymer
, chemical compound with high molecular weight consisting of a number of structural units linked together by covalent bonds (see chemical bond). The simple molecules that may become structural units are themselves called monomers; two monomers combine to form a dimer,
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Copolymer

 

a polymer whose macromolecules contain several types of monomeric units. In regular copolymers, the different units are arranged in periodic fashion. The simplest examples are copolymers of styrene with maleic anhydride and copolymers of certain olefins with SO2, constructed in the order . . . ABABAB . . . , where A and B are different types of monomeric units. More complicated regular sequences, with an alternating arrangement of units, are characteristic of, for example, the various amino-acid residues in certain proteins, such as the glycine-proline-hydroxyproline sequence in collagen. In irregular copolymers, the distribution of monomeric units is random, which is characteristic for many synthetic copolymers. In nucleic acids and most proteins, the irregular sequences of units are prescribed by a corresponding code, and it is these sequences that determine the biochemical and biological specificities of the corresponding compounds.

Copolymers in which the monomeric units of each type form rather long continuous sequences (blocks) that replace one another within the macromolecule are called block copolymers. One or several chains having a chemical composition different from that of the macromolecular chain may be added to the internal (nonterminal) monomeric units of the chain. Copolymers of this type are referred to as graft copolymers.

Materials with a given set of properties can be prepared by combining chemical units of various types in a single macromolecule. Thus, the synthesis of copolymers is one of the most effective means for modifying the properties of high-molecular-weight compounds.

REFERENCE

Entsiklopediiapolimerov, vols. 1–2. Moscow, 1972–74.

V. A. KABANOV

copolymer

[kō′päl·i·mər]
(organic chemistry)
A mixed polymer, the product of polymerization of two or more substances at the same time.
References in periodicals archive ?
PLA3 shows a slightly decreased viscosity compared to the linear PLA ex, which can be attributed to a changed chain topology and hydrodynamic volume through modification with the bulky copolymeric modifier.
p(HEMA-co-MAA) copolymeric network chains were synthesized by crosslinking HEMA and methacrylic acid to form stable networks with milky white colored hydrogels through free radical polymerization process.
In this respect, a series of AAm-based copolymeric hydrogels were synthesized by changing the content of NaSS and PEG.
In addition to isotropization during the thermal treatment, chemical reaclions (additional condensation and transreactions) in the melt and in the solid state take place at the interface of condensation polymers, resulting in the formation of a copolymeric interface, playing the role of a self-compatibilizer.
However, in many copolymeric PLCs, an overlap of the transitions is often evident leading to broad transition peaks.
In this work uniaxial tensile tests were performed on two polypropylene copolymeric materials manufactured by Montell Polyolefins and commercialized as Hifax Ca10A (Material A in this work) and Moplen Epd60R (Material B).
Most sources tend to refer to copolymeric structures between rigid and flexible segments.
In order to provide a direct experimental measurement of the stress in a pancake sample we prepared a supply several specimens of acrylanitrile butadiene acid copolymeric elastomers (1-3).
On the other hand, Colton (4) was able to produce a very fine cellular structure with a cell size of 5 [[micro]meter] in the copolymeric and nucleated PP utilizing a batch microcellular foaming technique.