SYNTHESIS AND CHARACTERIZATION OF THERMOTROPIC POLY(BENZOBISTHIAZOLE)S

Thermotropic polymers containing the benzo[1,2-d:4,5-d]bisthiazole-2,6 -diyl unit combined with 2,5-bis(n-alkoxy)-1,4-phenylene (Cn-PTBT) or 5-(alkyloxy)-1,3-phenylene units (Cn-PIBT) were synthesized via precur sor polyamides prepared by low-temperature solution polycondensation. The polyamides were converted into Cn-PTBT or Cn-PIBT by heating at 25 0-degrees-C. All polymers except for one containing 2,5-bis(n-butyloxy )-1,4-phenylene showed anisotropic melt phases in the range of 280-450 -degrees-C. Characterization of these polymers by differential scannin g calorimetry, thermal optical analysis, X-ray diffraction, and thermo gravimetric analysis is reported. The polymers were not stable at high temperatures due to decomposition of the alkyloxy side chains.