The FTIR spectra of the UBPU 1.4 and MBPU 1.4 films are represented in Fig 2. It is noticeable that the –NH peak for MBPU 1.4 appears at a lower wavenumber as compared with UBPU 1.4. Coleman et.al. [36] have reported that in case of H-bonded polyurethane the –NH bond appears at lower wavenumber as compared with the PUs devoid of H-bonding. Usually the hydrogen bonding (H-bonding) is formed between two types of proton donors i.e. (urethane N-H and urea N-H) and four types of …show more content…
As revealed from table 7, MBPU 1.4 exhibits shorter H-bond length, which, confirms its higher H-bonding as compared with UBPU 1.4. This result was predictable by taking into account the difference in reactivity of OH groups and the number of dangling chains in CO and MCO respectively. It is to be noted that the presence of the primary hydroxyl (OH) groups in terminal position of MCO renders higher reactivity towards the NCO groups in Tolonate TM X FLO 100 resulting in the formation of H-bonded N-H of relatively higher intensity. Moreover, the presence of less dangling chains [39] in MBPU inhibits the steric hindrance effect resulting in the formation of stronger H- bonds and enhanced intermolecular