3.2. Nuclear Magnetic Resonance (NMR) Spectroscopy

Proton nuclear magnetic resonance spectroscopy (Bruker AV3HD-400 NMR spectrometer, Birrica, MA, USA) was performed to characterise the PCL triol and PCLMA and allow calculation of the degree of methacrylation. 20 mg samples of polymer were solvated with 0.5 mL of deuterated chloroform and analysed at 400 Hz at room temperature. Spectra peaks were referenced to CDCl₃ at 7.26 ppm and identified with the help of a previous publication by Elomaa et al. [55] (see Figure 1). For quantitative analysis of degree of methacrylation, the integrals of peaks representing methacrylate protons at 6.09 ppm and 5.55 ppm (i, j) and the methylene group adjacent to the methacrylate group at 4.14 ppm (a′′) were integrated, relative to integral of the methyl group at 0.88 ppm (h). Analysis was performed using Mnova (Mestrelab).