Macromolecule

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Macromolecules (giant molecules) are very large molecules that consist of repeating, identical or different structural units (formal building blocks) and have a high molecular weight . The basic building blocks are mostly groups of atoms, but they can also be atoms. The masses of the basic building blocks are very small compared to the molecular mass. In technical chemistry these basic building blocks are called constitutional repeating units. Usually one speaks of macromolecules if the molecular mass is over 10,000 g · mol −1 . The term macromolecule was introduced by Hermann Staudinger in 1922 .

Macromolecular substances

Several series of natural and synthetic chemical substances are made up of macromolecules. These macromolecular substances are usually mixtures of macromolecules with a similar chemical composition or structure and only similarly large molecular weights . They are thus polydisperse and have a molar mass distribution . In practice, the behavior of the macromolecules of a macromolecular substance is the same, since - due to the size of the molecule - adding or removing structural units has no effect on the properties of the macromolecule.

Some macromolecular substances consist of largely identical macromolecules with a uniform molar mass . They are thus monodisperse. In the case of some natural, monodisperse macromolecular substances, such as certain proteins ( enzymes ), the biochemical properties of the macromolecule - contrary to the general rule - are highly dependent on the composition and the fine structure of the macromolecule.

The words polymer (high polymer) or biopolymer are often used synonymously with “macromolecular substances” . In the end, the word plastic also means macromolecular substances. These substances are the working area of macromolecular chemistry .

Classification

White natural silk - a natural macromolecular substance
Table tennis balls made from celluloid - a semi-synthetic macromolecular substance
PET bottle made from a synthetic macromolecular material

Macromolecular substances are divided into natural, semi-synthetic and synthetic substances.

Representatives of natural macromolecular substances are z. B .:

Representatives of semi-synthetic macromolecular substances are z. B .:

Representatives of synthetic macromolecular substances (plastics) are z. B .:

See also

Individual evidence

  1. Entry on macromolecule (polymer molecule) . In: IUPAC Compendium of Chemical Terminology (the “Gold Book”) . doi : 10.1351 / goldbook.M03667 Version: 2.3.1.
  2. Entry on macromolecules. In: Römpp Online . Georg Thieme Verlag, accessed on June 20, 2014.
  3. ^ MD Lechner, K. Gehrke and EH Nordmeier: Makromolekulare Chemie. 4th edition, Birkhäuser Verlag, 2010, ISBN 978-3-7643-8890-4 , pp. 48-170.