Synthesis of poly(1,3,4-oxadiazole-amide-ester)s and study of the influence of conformational parameters on their physical properties

Aromatic poly(1,3,4-oxadiazole-amide-ester)s have been synthesized by low temperature solution polycondensation reaction of equimolar amounts of aromatic diamines containing preformed 1,3,4-oxadiazole rings with diacid chlorides containing preformed ester linkages. The polymers showed high thermal stability with initial decomposition temperature being above 365 degrees C and glass transition temperature in the range of 215-260 degrees C. The weight average molecular weight was in the range of 91,000-257,000 and polydispersity is in the range of 1.64-5. The polymer films showed good mechanical properties with tensile strength in the range of 40-91 MPa, elastic modulus in the range of 2.22-3.98 GPa and elongation at break in the range of 1.85-7.37%. Conformational parameters of polymers have been calculated by Monte Carlo method with allowance for hindered rotation and discussed in relation with some physical properties.