American Chemical Society
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1H and 13C NMR Spectra of Highly Branched Poly(4-chloromethylstyrene). Signal Assignment, Structure Characterization, and a SCVP Kinetics Study

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journal contribution
posted on 2009-11-10, 00:00 authored by Hartmut Komber, Ulrike Georgi, Brigitte Voit
In this work, we present a detailed structural analysis of poly(4-chloromethylstyrene) (P(4-CMS)) by 1D and 2D NMR methods. A signal assignment and quantitative analysis of the different aliphatic structures of the polymer backbone were achieved. Combining signal integration of spectra taken in both C6D6 and CD2Cl2 as solvent, the content of terminal (T), vinyl-type linear (LV), condensation-type linear (LC), and dendritic (D) units and thus the degree of branching could be determined. The study is completed by a kinetics study of the polymerization of 4-CMS at 115 °C in chlorobenzene with CuCl/bpy as activator. The development of subunits is followed depending on vinyl group conversion and compared with a theoretical study of Müller et al. Obviously, the fractions of structural units cannot be predicted by a simple theoretical model due to the complexity of the mechanism of the atom transfer radical polymerization (ATRP). An increased content of LV units is rationalized by both a retarded deactivation resulting in multiple monomer addition steps and a higher reactivity of the secondary radical compared with the primary one.