Spectroscopic and Thermal Analysis of Polymers

The ¹H NMR and ¹³C NMR spectra were recorded on a Bruker AV300 MHz spectrometer (Billerica, MA, USA) using CDCl₃ as the solvent. The multiplicity of peaks is indicated as (bs) for broad signals, (s) singlet, (d) doublet, (t) triplet and (m) multiplet. The monomer conversion χ was evaluated by withdrawing aliquots of the reaction mixtures during the reaction to be analyzed by ¹H NMR spectroscopy according to the literature [21 (link),24 (link)].
The molar masses were investigated by gel permeation chromatography (GPC) using a Viscotek GPC system using tetrahydrofuran (THF) as eluent. The GPC module comprised a pump and degasser system (GPCmax VE2001, Malvern, Worcs, UK; 1.0 mL min⁻¹ flow rate), a Viscotek 302 TDA unit as detector (Malvern, Worcs, UK) and two columns for the analysis of different molar masses (2× PLGel Mix-B; dimensions 7.5 mm × 300 mm (all supplied by Malvern, Worcs, UK). The thermal characterization was performed with a TGA/DSC 3+ module (Mettler Toledo, Schwerzenbach, Switzerland). The thermal transitions were investigated from 25 °C to 360 °C under nitrogen flush (50 mL min⁻¹), increasing the temperature with a rate of 10 °C min⁻¹. The onset of decomposition was evaluated in a temperature range of 25 °C to 900 °C under air flush (50 mL min⁻¹) with a temperature increasing rate of 10 °C min⁻¹.