Polymers composed of macromolecules containing exclusively ethene-1,2-diyl (formerly vinylene) or substituted ethene-1,2-diyl constitutional repeating units in the backbone:
\[\ce{-CR^{1}=CR^{2}-}\] where
\(\ce{R^{1}}\) and
\(\ce{R^{2}}\) are each hydrogen or an alkyl, aryl, or heteroaryl group (structure-based polymer class name).
Notes: - Delocalization of electrons in conjugated chains gives to main-chain single bonds a partial character of double bonds, which restrict free rotations around these bonds which, therefore, show the cis-trans like isomerism. Four basic stereoregular polyvinylene chains can be derived:
- Polyvinylenes are almost exclusively prepared by polymerization of acetylene derivatives. Therefore, based on the source, they are mostly polyacetylenes.
Example: Polyvinylenes and their structure-based (first row) and source-based (second raw) names are:
Source:
PAC, 2022, 94, 15. 'Glossary of terms relating to electronic, photonic and magnetic properties of polymers (IUPAC Recommendations 2021)' on page 63 (https://doi.org/10.1515/pac-2020-0501)