| 초록 |
A self-polymerizable AB monomer, 4-fluoro-4’-(4-hydroxyphenyloxy)benzil, were prepared to afford poly(ether-ether-benzil). The monomer was synthesized by four-step reaction sequence in good yield. The polymerization was carried out in N-methyl-2-pyrrolidinone (NMP)/toluene mixture in the presence of potassium carbonate to give high molecular weight polymer, which could be precursor polymer to a series of 6-substituted polyphenylquinoxalines (PPQs). Although PPQs are well known class of high performance polymers with outstanding thermo-oxidative stability and excellent optical activity, high molecular weight PPQs could not be afforded from preformed AB phenylquinoxaline monomers due to the poor reactivity of monomer and the formation of cyclic oligomers. As an alternative approach to high molecular weight PPQs, post polymerization reaction between benzil units in the high molecular weight poly(ether-ether-benzil) and various 6-substituted 1,2-phenylenediamines was applied for the formation of quinoxaline units. The resultant polymers were amorphous and completely soluble with glass transition temperature in the range of 160-265 ºC and displayed good thermoxidative stabilities displaying 5 % weight loss temperature of 420-510 ºC in both air and nitrogen atmospheres. Depending upon the polarity of pendant groups, the glass transition temperatures of polymers were dramatically changed. The polymers display high fluorescence in NMP solution with absorption maxima around 360-380 nm and emission maxima around 430-450 nm. |
