Abstract: During the polymerization process of THF, active center can transfer to succinic anhydride and produce polyether-ester block copolymer.If TDIis added into the system,the relative velocity of polymerization and chain transfer reaction can be controlled.It is found that when the molar ratio of TDI/catalyst is 1, the polymerization can be accelerated, while the transfer rate decreases during the latter period of the reaction .However, when this ratio is 5/1, the propagation rate changes little, but the transfer rate increases.In the systems without TDI, with one time and five times moles of TDIas the mole of catalyst at 8℃, the apparent propagation rate constants of THF, k_p are 5.55×10^-3,7.10× 10^-3 and 8.10×10^-3 L/(mol·s), respectively; the transfer rate constants k_tr are 1.33 × 10^-3,0.43 × 10^-3 and 5.55×10^-3 L/(mol·s), respectively.

Key words: THF, TDI, CH₃COSbCl₆, Apparent polymerization rate constant