Synthesis and characterization of dendritic poly(arylene ether)s with functional groups and biodegradable hyperbranched aliphatic polyesters

Abstract

Hyperbranched polymers have gained much attention due to the availability of these materials by one-pot synthesis, and their interesting properties such as low viscosity and good solubility. In the first part, we synthesized linear and hyperbranced poly(arylene ether ketone)s with carboxylic acid groups from carboxlyic acid containing monomers. The hyperbranched polymer was prepared by using direct $A_2+B_3$ polymerization instead of $AB_2$ polymerization. 3,5-Dihydroxy-benzoic acid $(A_2 monomer)$ and 1,3,5-tris(4-fluorobenzoyl)benzene $(B_3 monomer)$ were condensed through nucleophilic aromatic substitution reaction. The linear and hyperbranched polymers with the carboxylic acid groups showed higher viscosity values than those of the corresponding polymers without carboxylic acid groups. In the second part, synthesis of hyperbranched aliphatic polyesters with hydroxyl terminal groups were attempted with 2,2-bis(hydroxymethyl)propioic acid (bis-MPA) as a $AB_2$ type monomer and Hafnium(Ⅳ) salts as an acid catalyst. Compared with other strong acid catalysts $(ex. p-toluene sulfonic acid, H_2SO_4)$, Hafnium (Ⅳ)-salts did not induce the transesterification and etherification during the polymerization. The well defined hyperbranched aliphatic poly(bis-MPA) was obtained without gelation.