Monomer

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Monomers ( ancient Greek μόνος monos 'one', 'single' and μέρος meros 'part', 'part') are low-molecular, reactive molecules that can combine to form unbranched or branched polymers . Monomers can be individual substances, but also mixtures of different compounds. In the first case homopolymers are formed , in the second copolymers ( heteropolymers ).

chemistry

Typical monomers for plastics
Ethene structural.svg

Ethene (ethylene)

Propene Structural Formula V1.svg

Propene (propylene)

Vinyl Chloride Structural Formula V1.svg

Vinyl chloride (VC)

Acrylamide Structural Formula V1.svg

Acrylamide

In polymer chemistry , monomers are in principle all chemical compounds in which polymers can be formed through polyreactions . Monomers are often molecules with a C = C double bond or with at least two functional groups per molecule. Ring-shaped structures such as caprolactam can also be used as monomers for polyreactions. Monomers can be linked to polymers by chain polymerization , polycondensation or polyaddition .

There are also inorganic monomers, e.g. B. the orthosilicic acid H 4 SiO 4 , which polycondense to polysilicic acids, see silicas .

biochemistry

In biochemistry , the word "monomer" occasionally describes a subunit (also called a subunit ) as an individual component of a complex that is composed of several components. In connection with protein complexes , protein subunits are meant that are non-covalently linked to one another. Under suitable conditions, the subunits can oligomerize or associate or aggregate via intermediate stages ( dimer , trimer , tetramer , ...) .

See also

Individual evidence

  1. Entry on monomeric . In: IUPAC Compendium of Chemical Terminology (the “Gold Book”) . doi : 10.1351 / goldbook.M04017 Version: 2.3.1.
  2. Entry on monomer molecule . In: IUPAC Compendium of Chemical Terminology (the “Gold Book”) . doi : 10.1351 / goldbook.M04019 Version: 2.3.1.
  3. Entry on monomers. In: Römpp Online . Georg Thieme Verlag, accessed on June 13, 2014.
  4. ^ MD Lechner, K. Gehrke and EH Nordmeier: Makromolekulare Chemie , 4th edition, Birkhäuser Verlag, 2010, pp. 48–170, ISBN 978-3-7643-8890-4 .
  5. a b Keyword sub-unit in: Hans-Dieter Jakubke, Ruth Karcher (Ed.): Lexikon der Chemie , Spektrum Akademischer Verlag, Heidelberg, 2001.