HIGH ALPHA-TRANSITION OF NEW POLYAMIDES BASED ON DIAMANTANE

A series of new polyamides were synthesized by direct polycondensation of the 1,6-bis(4-aminophenyl)diamantane with various dicarboxylic aci ds. The soluble polyamides had high inherent viscosities, ranging from 0.73 to 1.21 dL/g. Polyamides derived from 5-tert-butylisophthalic ac id and (+/-)-1,3-cyclohexanedicarboxylic acid were soluble in N-methyl -2-pyrrolidone (NMP) and pyridine. When NMP and N-dimethylacetamide (D MAc) were added with 3% (w/v) LiCl, the solubilities of polyamides der ived from 4,4'-oxybis(benzoic acid) and cis-1,4-cyclohexanedicarboxyli c acid were markedly enhanced. Polyamides had tensile strengths of up to 87.8 MPa, elongation to breakage values of up to 19.3%, and initial moduli of up to 2.1 GPa. Dynamic mechanical analysis (DMA) reveals th at the polyamides have three relaxations. Their a relaxations occurred at high temperatures, ranging from 380 to 462 degrees C. Three of pol yamides exhibited good retention of storage modulus (above 10(8) Pa) a t a temperature exceeding 410 degrees C. (C) 1998 John Wiley & Sons, I nc.