Synthesis and characterization of poly(aryiene ether)s containing 6-(4-hydroxyphenyl)pyridazin-3(2H)-one or 6-(4-hydroxyphenyl)pyridazine moieties

摘要

A series of novel soluble pyridazinone- or pyridazine-containing poly(arylene ether)s were prepared by a polycondensation reaction. The pyridazinone monomer, 6-(4-hydroxyphenyl)pyridazin-3(2H)-one (1), was synthesized from the corresponding acetophenone and glyoxylic acid in a simple one-pot reaction. The pyridazinone monomer was successfully copolymerized with bisphenol A (BPA) or 1,2-dihydro-4-(4-hydroxyphenyl)phthalazin-1(2H)-one (DHPZ) and bis(4-fluorophenyl)sulfone to form high-molecular-weight polymers. The copolymers had inherent viscosities of 0.5-0.9 dL/g. The glass-transition temperatures (T-g's) of the copolymers synthesized with BIPA increased with increasing content of the pyridazinone monomer. The T-g's of the copolymers synthesized from DHPZ with different pyridazinone contents were similar to those of the two homopolymers. The homopolymers showed Tg's from 202 to 291 degrees C by differential scanning calorimetry. The 5% weight loss temperatures in nitrogen measured by thermogravimetric analysis were in the range of 411-500 degrees C. 4-(6-Chloropyridazin-3-yl)phenol (2) was synthesized from 1 via a simple one-pot reaction. 2 was copolymerized with 4,4'-isopropylidenediphenol and bis(4-fluorophenyl)sulfone to form high-T-g polymers. The copolymers with less than 80 mol % pyridazinone or chloropyridazine monomers were soluble in chlorinated solvents such as chloroform. The copolymers with higher pyridazinone contents and homopolymers were not soluble in chlorinated solvents but were still soluble in dipolar aprotic solvents such as N-methylpyrrolidinone. The soluble polymers could be cast into flexible films from solution.