Ring-opening polymerization of ε-caprolactone catalyzed by rare earth chloride

Ring-opening polymerization of e-caprolactone catalyzed by rare earth chloride dissolved in N, N-dimethy1formamide and adding a small amount of propylene oxide was studied. The optimum conditions for the ring-opening polymerization of CL are as follows. In the bulk polymerization: n (DMF)/n (LaCl3) = 10, n(PO)/n(LaCl3) = 20, aging temperature: 30 degrees C, aging time: 1 h, c(CL) = 7. 91 x 10(-3) mol/L, c(LaCl3) = 1.58 x 10(-5) mol/L, the polymerization carried out at 30 degrees C for 1 h, yield = 83.3%, (M) over bar (nu) = 1.93 x 10(4). In the solution polymerization: n (DMF) /n (LaCl3) 10, n (PO)/n (LaCl3) = 20, aging temperature: 30 degrees C, aging time: 1 h, toluene as the solvent, c(CL) 4.22 x 10(-3) mol/L, c(LaCl3) = 8.43 x 10(-6) mol/L, the polymerization was carried out at 30 degrees C for 2 h, yield = 62.9%, (M) over bar (nu) = 1.21 x 10(4).