Synthesis and characterization of poly(arylene ether sulfone)s with controlled molecular weights and narrow polydispersities through chain-growth polycondensation

Abstract

Synthesis of linear and multi-arm poly(arylene ether sulfone) with controlled molecular weights and narrow polydispersities by chain-growth polycondensation technique was developed. Chain-growth polycondensation reaction was carried out by using various initiators activated by amide and trifluoromethyl group ($CF_3-B_1$ mono-intiator 6, $CF_3-B_2$ di-intiator 8, $CF_3-B_3$ tri-intiator 10, and $CF_3-B_4$ tetra-intiator 13) and AB’type monomer 3. The reaction was monitored by 1H NMR and GPC to investigate the kinetics of polymerization. The results indicated that polymerization proceeded in a living fashion up to conversion at least 90%, and the number of end group per initiator unit was maintained as close to 1 suggesting that self-polymerization of monomers themselves and transetherification was efficiently suppressed. Consequently, well-defined linear and 2~4 arm polymers were obtained with desired molecular weights and PDI<1.3. Also the absolute molecular weight was confirmed by MALDI-TOF. The architecture of polymers affected upon thermal and physical properties of polymers having similar molecular weights and similar arm length from DSC, TGA, and solution viscosity measurements. $CF_3-2A-PAES$ 17 has higher solution viscosity due to the linear shape, and $CF_3-4A-PAES$ 20 has lower $T_g$ and lower thermal stability due to short arm length, under the same molecular weight condition.