Synthesis of Cyclic Oligoesters and Their Rapid Polymerization to High Molecular Weight

Abstract

We report advances for both synthesizing cyclic oligoesters and tailoring their physical properties to make ring-opening polymerization more practical for polyester manufacturing. Solution and suspension methods provide cyclic oligoesters rapidly with high yield and purity. Both methods can be adapted to continuous process operation using simple, inexpensive raw materials. Synthesis methodology influences the distribution of cyclic ring sizes. Nonequilibrium cyclic oligomer distributions produce variant crystal morphologies. Some kinetic cyclic oligoester mixtures have melting points remarkably reduced from those previously reported for the pure components. New mixed solvent syntheses, cyclic cooligomers, and ring-opening copolymerizations are demonstrated. The kinetics and efficiencies of cyclic oligoester polymerization to high molecular weight for homopolymer and copolymers are characterized. A new approach for a continuous, melt-phase ring-opening polymerization is demonstrated which avoids the high temperatures normally required to melt cyclic oligomers.

New Strategy for Enzymatic Synthesis of High‐Molecular‐Weight Poly(butylene succinate) via Cyclic Oligomers

“…In order to produce a high-molecular-weight polyester, the ring-opening polymerization of cyclic oligomers could become a new revolutionary means of manufacturing polyesters that are now typically synthesized by a polycondensation reaction. [8] Previously, a chemical recycling method was reported in which poly(butylene adipate) was degraded by lipase in an organic solvent to produce repolymerizable cyclic oligomers. [9] However, details of the lipase-catalyzed ring-opening polymerization of cyclic oligomers other than lactones with respect to the polymer synthesis have not yet been reported.…”

Polycondensation

“…It is also possible to prepare low molecular weight mixtures of ring molecules for further reactive processing (using, for instance, anion polymerization), starting with monomers [8] or even with recycled polymer [9], by dilution with inert solvents and a suitable catalyst (see also Section 3.1.7). The discussion of these otherwise interesting processes falls outside the scope of this chapter.…”

“…(9), to apparent equilibrium ratio K and by-product concentration ½W . (9), to apparent equilibrium ratio K and by-product concentration ½W .…”

Effect of hard segment length on the properties of poly(ether ester) elastomer prepared by one pot copolymerization of poly(ethylene glycol) and cyclic butylene terephthalate

“…A variety of cyclic polyester oligomers have been successfully prepared and researchers have used the cyclic polyester oligomers to prepare linear high molecular weight polyester [15][16][17][18][19][20][21]. Cyclic oligomers of poly(butylene terephthalate) (CBT) are now available commercially.…”