Synthesis and ring-opening copolymerization of cyclic aryl ester dimers

Two kinds of cyclic aryl ester dimers have been synthesized by reaction of phthaloyl dichloride with bisphenols via interfacial polycondensation. The cyclic dimers readily undergo anionic ring-opening polymerization or copolymerization in the melt by using sodium benzoate as the initiator, producing linear, high molecular weight polyesters. The contents of cyclic dimers in the homopolymers P1, P2, and copolymer P12 are 13.7%, 10.2%, 2.9%, respectively, which indicates that ring-opening copolymerization of cyclic dimers may impel the conversion of cyclic dimers and decrease the content of cyclic dimers in the resulting copolymer. Moreover, the isothermal chemorheology of the ring-opening copolymerization of cyclic dimers indicates that the reactive molten mixture has low shear viscosity and the viscosity increases slowly in the initial stage of ring-opening polymerization.

Graphical abstractRing-opening copolymerization (co-ROP) of cyclic aryl ester dimers could promote the chain-ring equilibration toward the formation of linear polymer and decrease the content of cyclic dimers in the resulting polymer, since ring-opening polymerization (ROP) of aromatic cyclic oligomers is driven by entropy changes.Figure optionsDownload full-size imageDownload as PowerPoint slide