Highly branched poly(arylene ether)s via oligomeric A(2)+B-3 strategies

Abstract

Branched poly(arylene ether)s were prepared in an oligomeric A(2) + B-3 polymerization of phenol endcapped telechelic poly(arylene ether sulfone) oligomers as A(2) and TFPPO as trifunctional monomer B-3. The molar mass of the A(2) oligomer significantly influenced the onset of gelation and the DB. A high level of cyclization during polymerization of low molar mass A oligomers (U-3 = 660 and U-6 = 1200 g h conversion of functional groups in the mol(-1)) led to a high absence of gelation, and the level of cyclization reactions in the polymerization decreased as the molar mass of the A, oligomer was increased. The pronounced steric effect in the polymerization of higher molar mass A(2) oligomers (U-8 = 1800 and U-16 = 3400 g (.) mol(-1)) resulted in low reactivity of the third aryl fluoride in the B3 monomer. As a result, only slightly branched (U-8 = 1800 g (.) mol(-1)) or nearly linear (U-16 = 3400 g (.) mol(-1)) high molar mass products were obtained with higher molar mass A(2) oligomers. The branched polymers exhibited lower Mark-Houwink exponents and [eta] relative to linear analogs, and differences between the branched polymers and linear analogs were less significant as the molar mass of the A oligomers was increased due to a decrease in the overall DB.