Synthesis and characterization of linear and dendritic poly(arylene ether)s through nucleophilic aromatic subsitution reaction

Abstract

Syntheses of new linear and dendritic poly(arylene ether)s were attempted by using the nucleophilic aromatic substitution reaction $(S_NAr)$. First, cyano substituted poly(biphenylene oxides) (CN-PBPOs) were synthesized via nitro-displacement reaction in mild condition. The CN-PBPOs were amorphous and soluble in common organic solvents. Tough flexible film was formed on solution casting. High molecular weight poly(arylene thioether)s were prepared from the dithiol monomers protected with N-propyl-S-carbamate group and dihalide monomers. The protected dithiol was deprotected by organic bases like DBU and the subsequent polymerization reaction was carried out at mild condition. New high molecular weight poly(arylene ether ketone)s were prepared from the unsymmetrical dichloro monomer containing pyridine moiety. Also, soluble aromatic polyamides were synthesized from the pyridine containing monomer. The improved solubility of these aramid polymers was attributed to the conformational change of the polymer chains due to the unsymmetric pyridyl ether linkage along the polymer main chain. Hyperbranched poly(phenylene oxide) was successfully synthesized from $AB_2$ type monomer via Ullmann polycondensation. Water-soluble hyperbranched polymer was also prepared by modification of this polymer through lithiation and subsequent carboxylation. The carboxylate-terminated hyperbranched poly(phenylene oxide) behaved as a unimolecular micelle in aqueous solution and acted as a host molecule to take some non polar organic molecules into the inside the of micelle. New hyperbranched poly(arylene ether phosphine oxide) (HPEPO) with excellent transparency in UV-region was prepared from $AB_2-type$ monomer via nucleophilic aromatic substitution reaction. The mixture consisting of HPEPO (65 wt %), MBHP (20 wt%), and DIAS (10 wt%) in NMP was found to be an alkaline-developable negative-type photosensitive resist with the sensitivity of 9mJ/㎠ and the contrast of 1.6. The negati...