ABSTRACT
The cure conversions for epoxy and amine groups were calculated by using, respectively, the 4530 cm - 1 epoxy combination band and the 6500 cm - 1 amine band [16]. The 4623 cm - 1 aromatic C-H ring stretch combination band was considered as reference. Thus, the amine (Xa) and the epoxy (Xe) conversions were determined using the ratio of the respective peak areas (A) by:
(3)
2.2.4. Nuclear magnetic resonance spectroscopy (NMR). For proton and carbon Nuclear Magnetic Resonance (!H and 13C NMR) a Bruker AC 400 spectrometer was used with the sodium salt of deuterated trimethyl silyl propionic acid (TSPd4) as the internal standard. Analyses were carried out at 293 K using deuterated water in which pure IPDA and modified IPDA were perfectly soluble. By comparing pure IPDA and modified IPDA spectra it was possible to determine the differences in chemical shifts for the equivalent carbon nuclei.
