Synthesis, kinetic study, and application of Ti[O(CH₂)₄OCH==CH₂]₄ in ring-opening polymerization of ε-caprolactone and radical polymerization

Ti[O(CH₂)₄OCH==CH₂]₄, used for the ring-opening polymerization (ROP) of ε-caprolactone, was synthesized through the ester-exchange reaction of titanium n-propoxide and 1,4-butanediol vinyl ether, and its chemical structure was confirmed by nuclear magnetic resonance (¹H NMR) and thermogravimetric analysis (TGA). The mechanism and kinetics of Ti[O(CH₂)₄OCH==CH₂]₄-initiated bulk polymerization of ε-caprolactone were investigated. The results demonstrate that Ti[O (CH₂)₄OCH==CH₂]₄-initiated polymerization of ε-caprolactone proceeds through the coordination-insertion mechanism, and all the four alkoxide arms in Ti[O (CH₂)₄OCH==CH₂]₄ share a similar activity in initiating ROP of ε-caprolactone. The polymerization process can be well predicted by the obtained kinetic parameters, and the activation energy is 106 KJ/mol. Then, the rheological method was employed to investigate the feasibility of producing the crosslinked poly(ε-caprolactone)-poly (n-butyl acrylate) network by using Ti[O(CH₂)₄OCH==CH₂]₄ as the ROP initiator. The tensile test demonstrates that the in situ generated crosslinked PCL-PBA network in PMMA matrix provides the possibility of ameliorating the tensile properties of PMMA.