Synthesis and characterization of novel fluorinated azopolyamides

Summary

Novel soluble fluorinated azopolyamides 4a-d were synthesized by reacting 2-trifluoromethyl-4,4’-diaminodiphenyl ether 2 with various azodibenzoyl chlorides 3a-d using the low temperature solution polycondensation technique. The fluorinated diamine 2 was prepared through the nucleophilic substitution reaction of 4-nitrophenol and 2-chloro-5-nitrobenzotrifluoride via catalytic reduction catalytic reduction with hydrazine and Pd/C. All of the fluorinated azopolyamides exhibited excellent solubility at room temperature in strong polar solvents such as N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and N-methyl-pyrrolidinone (NMP). Inherent viscosities of the azopolyamides were found to range from 0.85 to 1.35 dl/g, and those azopolyamides could be cast into flexible and tough films from DMAc solutions. The azopolyamides showed that the glass transition temperatures (T_g) were between 231 and 259^oC, and the char yields of all the azopolyamides except for 4d at 800^oC in nitrogen atmosphere were above 47%. Furthermore, all the azopolyamides exhibited thermal and photochromic properties.