Title: degree of branching
Long Title: IUPAC Gold Book - degree of branching
DOI: 10.1351/goldbook.09604
Status: current

Definition
Parameter characterizing the branched architecture of a hyperbranched polymer, which is equal to unity for a polymer that contains no linear or semi-dendritic constitutional repeating unit and is equal to 0 for a polymer that contains no dendritic or semi-dendritic constitutional repeating unit.

Notes
1) Several definitions of the degree of branching have been proposed for hyperbranched polymers obtained by polycondensation of \({\rm{AB}}_2\mbox{-}\rm{type}\) monomers and for those obtained by polycondensation of more complex monomer systems. The definition by Hölter et al. is: \(D_{\rm{br}} = 2 x_{\rm{D}}/(2 x_{\rm{D}} + x_{\rm{L}})\), where \(x_{\rm{D}}\) and \(x_{\rm{L}}\) are the mole fractions of dendritic and linear units, respectively.
2) The degree of branching of a dendrimer is equal to one. However, a polymer with the degree of branching equal to one is not necessarily a dendrimer. It can be a hyperbranched polymer, since the degree of branching does not per se take into account the regularity and symmetry of the molecules that compose it.
3) The degree of branching of a linear polymer is equal to 0.

Related Terms
- dendritic: https://goldbook.iupac.org/terms/view/09610
- hyperbranched polymers: https://goldbook.iupac.org/terms/view/09618
- linear: https://goldbook.iupac.org/terms/view/09622
- semi-dendritic constitutional repeating unit: https://goldbook.iupac.org/terms/view/09629

Source
- PAC, 2019, 91, 523. 'Nomenclature and terminology for dendrimers with regular dendrons and for hyperbranched polymers (IUPAC Recommendations 2017)' on page 528 (https://doi.org/10.1515/pac-2016-1217)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/09604/html
- json: https://goldbook.iupac.org/terms/view/09604/json
- xml: https://goldbook.iupac.org/terms/view/09604/xml

Citation: Citation: 'degree of branching' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.09604
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Accessed: 2026-08-09T17:59:05+00:00