Synthesis and characterization of A2+ B3-type hyperbranched aromatic polyesters with phenolic end groups

Abstract

Abstract Hyperbranched (hb) aromatic polyesters with phenolic end groups were synthesized according to the A 2 + B 3 approach both, by solution polymerization and by melt (bulk) polymerization with different monomer ratios (A 2 :B 3 ). The hb polyesters produced from solution polymerization exhibited higher yields, molar masses and glass transition temperature ( T g ) compared to the products prepared in the melt. The resulting hb aromatic polyesters from the A 2 + B 3 approach were also compared with their properties to hb aromatic polymers produced from the well known AB 2 monomer 3,5-bis(trimethylsiloxy)benzoyl chloride. Both types of hb aromatic polyesters possess high T g , high thermal stability and good solubility in common organic solvents. A typical melt viscosity behavior with shear thinning effect was also observed for both. Thus similar polymer properties compared to melt-condensed products were obtained with the A 2 + B 3 approach by solution polycondensation possessing the advantage of easy monomer availability and much milder polymerization conditions (at room temperature in solution) compared to the AB 2 approach.