Structural characterisation of poly(amidoamine) networks via high-resolution magic angle spinning NMR

A comprehensive structural characterisation of cross-linked insoluble poly(amidoamine) (PAA) networks was performed by high-resolution magic angle spinning (HRMAS) NMR spectroscopy. Model samples with 20%, 40% and 80% cross-linking degrees were prepared and the best conditions to obtain high-resolution spectra in the gel phase determined. Whereas the samples with 20% and 40% cross-linking degrees could be exhaustively resolved and described, the sample with 80% cross-linking degree could not be characterised by this technique owing to insufficient mobility of the polymer segments. Even with this limitation, the method developed in this study can be reasonably considered as a general one, which enables exhaustive characterisation of cross-linked PAA networks of biomedical interest.