Structural element
In chemistry, a structural element (also called a structural fragment) is a characteristic part of the structural formula of a larger molecule .
In a polymer , the smallest repeating grouping is called the structural element. The structural element can be smaller, the same size or larger than a basic module.
- Example:
- In polyethylene , the monomer ethene forms the basic building block for the grouping (–CH 2 = CH 2 -) and the structural element is a methylene group (–CH 2 -).
- In polypropylene , the monomer propene is the basic building block of the grouping (-CH 2 = CH (CH 3 )) - and the structural element is the double-bonded grouping -CH 2 = CH (CH 3 ) -.
- in polyethylene terephthalate (PET), ethylene glycol and terephthalic acid are the monomers. The basic building blocks are the –O – CH 2 –CH 2 –O– groups and the double-bonded diacyl radical of terephthalic acid.
Individual evidence
- ^ Siegfried Hauptmann : Organic Chemistry , 2nd edition, VEB Deutscher Verlag für Grundstoffindindustrie, Leipzig 1985, p. 723, ISBN 3-342-00280-8 .