High optical transparency and low dielectric constant of novel organosoluble poly(ether ketone amide)s derived from an unsymmetrical diamine containing trifluoromethyl and methyl pendant groups

摘要

A series of novel fluorinated poly(ether ketone amide)s(PEKAs)were prepared from an unsymmetrical aromatic diamine,(4'-(4"-amino-2"-trifiuoromethylphe-noxy)-3',5'-dimethylphenyl)(4-aminophenyl)-methanone(1),with various aromatic dicarboxylic acids using the phosphorylation polycondensation technique.The PEKAs had inherent viscosities ranging from 0.43 to 0.65 dl/g.All the fluorinated PEKAs could be soluble in many polar organic solvents such as n-methyl-2-pyrrolidinone(NMP),N,N'-dimethylacetamide(DMAc),N,N'-dimethylformamide(DMF),dimethyl sulfoxide(DMSO),and tetrahydrofuran(THF).Flexible and tough polymer films could be prepared by casting from DMAc solvent.The PEKA films exhibited high optical transparency with a cutoff wavelength of 354- 365 nm and good mechanical properties with tensile strengths of 78-98 MPa and elongations at break of 11.5-18.5%.They showed glass-transition temperatures in the range of 288-323 °C and the onset decomposition temperatures in the range of 450-461 °C in nitrogen atmosphere.Meanwhile,the PEKA films possessed low dielectric constants of 1.98-2.71 at 1 MHz and low moisture absorption(<2%).Due to their properties,the fluorinated PEKAs could be considered as photoelectric and microelectronic materials.