writer：Qingfu Ban, Jie Kong*
keywords：Long-chain Hyperbranched Polymers, HyperMacs, Intramolecular Cyclization
source：期刊
specific source：Polymer Chemistry, 2016, 7, 4717-4727
Issue time：2016年

Qingfu Ban and Jie Kong*, Intramolecular Cyclization of Long-chain Hyperbranched Polymers (HyperMacs) from A2+B3 Strategy, Polymer Chemistry, 2016, 7, 4717-4727 (Communication)

http://pubs.rsc.org/en/content/articlelanding/2016/py/c6py00986g

Abstract: The well-defined hyperbranched polymer with long-chain backbones between branched points (HyperMacs) is an emerging issue in topological polymers. Owing to the difficult discrimination of branching points interfered or overlapped by long-chain backbones in nuclear magnetic resonance signals, the fine identification and quantitative characterization of intramolecular cyclization and the calculation of degree of branching for HyperMacs are always challenges. In this contribution, a convenient expression of macro-cyclic index (m-CI) was presented and deduced as the ratio of NA/NB of HyperMacs to that of their completely intramolecular cyclized analogues. The physical meaning of m-CI is the similarity of HyperMacs to their completely cyclized analogues. Accordingly, the m-CI closer to 1 means high degree of intramolecular cyclization, even complete cyclization. The experiment validation via model polymers indicates that m-CI is a facile parameter to analyze intramolecular cyclization of HyperMacs. The increase of chain length of backbones between branched points can enhance intramolecular cyclization of HyperMacs accompanied with the increase of m-CI value. As an original contribution to polymer science, the presentation of m-CI overcomes the difficult problem of quantitative characterization of intramolecular cyclization in long-chain hyperbranched polymers, which is helpful to well understand their relationship between topological structures and properties.