The DSC thermogram of the polymer PIFB shows glass transition temperature ([T.sub.g]) at -23[degrees] C and melting temperature ([T.sub.m]) at 72[degrees] C [14, 15] which are shown in Figure 4 and the values are in Table 2.
From the X-ray diffractogram, it is observed that PIFB is amorphous in nature.
The polyester PIFB was successfully synthesized by transesterification and melt polycondensation method and was characterized.