The chemical composition analysis of the formulated microcapsules was carried out using FTIR, indicating possible amine reacting during polymerization and as a result the creation of new bonds as well as the decrease of core concentration. It can be seen from Fig. 10 that the pure, liquid core material (AMP) has an overall higher IR transmittance compared to the encapsulated sample, this is especially the case for 3000‒3500 cm
‒1 IR spectra range. The primary interest in the FTIR spectra is the N‒H bonds from the amine groups and the O‒H bonds from the propanol groups. Both the N‒H bonds and the O‒H bond are present in the FTIR spectra (Fig. 10) in the range of 3500‒3200 cm
‒1, making it harder to distinguish between the two bonds as they have overlapping infrared transmittance absorbance. However, the bimodal nature of the first two peaks, suggests the presence of primary amines whereas the third peak suggests the hydroxyl group [
30]. The N‒H bond stretch transmittance in the range of 3250 to 3650 cm
‒1 decreases after encapsulation, which is suggesting a reduction in the free AMP due to polymerisation reaction between the amine and shell material [
30]. This reduction in AMP is not favorable because it would affect the CO
2 absorption as less AMP is available to react with CO
2 to form carbamate ions. However, the most likely reason for the reduced peaks compared to the pure liquid AMP is due to a lower amount of the encapsulated solvent. Though there is the possibility of
in-situ polymerisation of the amine group from AMP [
31], amine and the hydroxyl group (‒OH) both have the same probability of providing the required hydrogen for the formation of the shell material.