Journal of Polymer Science Part A: Polymer Chemistry, Vol.40, No.11, 1781-1789, 2002
Polyterephthalamides with naphthoxy-pendent groups
A series of new aromatic polyamides having pendent naphthoxy groups were synthesized by the triphenyl phosphite-activated polycondensation of (2-naphthoxy)terephthalic acid (NOTPA) with various aromatic diamines in a medium consisting of N-methyl-2-pyrrolidone (NMP), pyridine, and calcium chloride. The diacid monomer NOTPA was prepared from the nitro displacement of dimethyl 2-nitroterephtha-late with the potassium naphthoxide of beta-naphthol, followed by base-induced ester hydrolysis. All the resulting polymers were noncrystalline and readily soluble in aprotic polar solvents such as NMP and N,N-dimethylacetamide. Almost all the polymers could be solution-cast to tough, creasable amorphous films with good mechanical properties, the values of tensile strengths ranging from 90 to 124 MPa with initial moduli ranging from 1.72 to 2.51 GPa. Except for two examples, all the other polyamides displayed discernible glass transitions between 189 and 248 degreesC in the differential scanning calorimetric traces. These polyamides showed insignificant decomposition below 400 degreesC in nitrogen or air.
Keywords:aromatic polyamides;(2-naphthoxy)terephthalic acid;bulky pendent group;solubility;thermal properties;high performance polymers;high temperature materials;polyamides