Abstract
AbstractTopological considerations concerning the ratio of linear, imperfectly branched, dendritic and terminal units in hyperbranched polymers based on AB2, AB3 and ABm (m≥2) type monomers are summarized. The reaction of AB2 monomers with a core molecule of the structure Bf is also treated. For larger hyperbranched polymers based on AB2 monomers the fraction of terminal units has to be equal to the number of dendritic units. A general expression for the degree of branching (DB) is derived for AB2 systems, which is based on the number of dendritic and linear units. The expression is valid for low molecular weight as well as high molecular weight hyperbranched polymers in contrast to the commonly used expression based on dendritic, linear and terminal units. DB may not exceed 0.5 in hyperbranched polymers based on AB2 systems (0.44 in AB3 systems). Furthermore, a general expression for DB in hyperbranched polymers based on ABm monomers is derived. Consequences for signal ratios in NMR‐spectra of hyperbranched polymers are discussed. The expressions presented allow verification of NMR‐integration ratios obtained experimentally on the basis of model compounds.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
