FTIR results are shown in Figure 1. polyurethane N-H groups consist of, hydrogen
bonded (3330 cm
-1
) and non-hydrogen bonded groups (3400 cm
-1
). More than 95% of
hydrogen bonds in HTPB polyurethanes occur between N-H hydrogen bonded groups
in hard segment phase [4]. If phase separation develops via annealing, there is an
increased population of hydrogen bonded N-H groups in hard segment phase.
Furthermore C=C bond (1640 cm
-1
) is chosen as reference peak. It is also mentioned
in the literature that there is no interference of peaks in HTPB based polyurethanes
[5]. Therefore one can choose the relative intensity of N-H hydrogen bonded peak to
C=C bond peak in HTPB as a proof for qualitative detection of phase separation
evolution through annealing. Experiments showed that as the hard segment content of
polyurethanes as well as type of polyol affect on thermo mechanical properties as
well as phase separation of polyurethanes. AFM results show that one can recognized
relationship between hard segment content of and domain sizes in polyurethanes.