端羟基超支化聚酯分子结构的表征.

n张杰; 杨康; 张志平; 胡春圃

The molecular structure of second generation hydroxyl terminated aliphatic hyperbranched polyester（HB-20）was characterized by nuclear magnetic resonance（NMR）analyses,including onedimensional（1D）NMR technique(1H-NMR,13C-NMR and distortionless enhancement by polarization transfer（DEPT）NMR spectra)and two-dimensional（2D）NMR technique（heteronuclear single quantum coherence（HSQC）NMR and heteronuclear multipe bond coherence（HMBC）NMR spectra）.Firstly,the peaks of the 1H-NMR and 13C-NMR spectra were initially assigned,and the four types of carbon atoms（CH3,CH2,CH,and quaternary carbon atom C*）in the HB-20 were distinguished by DEPT NMR spectra.Secondly,the detailed molecular structure information was further obtained by 2D NMR analysis.From the HSQC spectrum,the 13C-1H chemical shift correlation spectroscopy spectrum contained all the directly linked 13C-1H coupling relationships,and the positions of the related 1H and 13C in the molecular structure were determined;from the HMBC spectrum,the 13C and 1H coupling information separated by 2-3 chemical bonds was obtained,and the C-C correlation was confirmed to determine the molecular skeleton information of HB-20.According to the NMR analysis,the three relative peak areas of the confirmed T-CH3,L-CH3,and D-CH3 structures in the 1H-NMR spectrum were determined to be 2.55,3.97 and 1.00 respectively,and the average degree of branching（DB）of HB-20 was calculated as 0.47.Moreover,the average molecular weight of HB-20 was calculated as 1 876 by NMR analysis,which was closed to that obtained from the hydroxyl value titration,about 1 878.In summary,the molecular structure of HB-20 was clearly characterized

CHEMICAL bonds; MOLECULAR structure; NUCLEAR magnetic resonance; MOLECULAR weights; QUANTUM coherence; ATOMS

Journal of Functional Polymers, 2019, Vol 32, Issue 2, p206

1008-9357

Academic Journal

10.14133/j.cnki.1008-9357.20180614002