Preparation of Poly(ether ether ketone) Dendrimers by the Divergen Method

Abstract

New highly branched poly(ether ether ketone) dendrimers were synthesized by the divergent approach through aromatic nucleophilic substitution reactions. 3,5-Dimethoxy-4′-(4-fluorobenzoyl)diphenylether, 1, and 1,3,5-tris[p-(3,5-dihydroxyphenoxy)phenyl]benzene, G0-OH, were used as a building block and starting core, respectively. The reaction of 1 with G0-OH gave the first-generation dendrimer (G1-OMe), which possessed 12 methoxy groups on the periphery. After the methoxy groups were converted to hydroxy groups by treatment with pyridine hydrochloride, the resultant phenol functionality (G1-OH) was allowed to react with 1 to yield the second-generation dendrimer (G2-OMe) which possessed 24 methoxy groups. By repeating these procedures G3-OMe dendrimer and G3-OH dendrimer possessing 48 methoxy and hydroxy groups, respectively, on the periphery were obtained. 1H and 13C NMR spectra were consistent with the structures of these dendrimers. Molecular weights and molecular weight distribution determined by gel permeation chromatography indicated that the dendrimers possessed remarkably narrow molecular weight distribution. Analysis was made of these structurally unambiguous dendrimers by matrix-assisted laser desorption ionization time of flight (MALDI-TOF) mass spectroscopy. The characteristics of these dendrimers, G n -OMe and G n -OH, such as solubility and thermal properties were compared.