ɛ‐caprolactone and lactide polymerization promoted by an ionic titanium(IV)/iron(III) polynuclear halo‐alkoxide |
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| Authors: | Cristiano Egevardt Siddhartha O. K. Giese Alan D. da C. Santos Andersson Barison Eduardo L. de Sá Arion Zandoná Filho Thiago A. da Silva Sônia F. Zawadzki Jaísa F. Soares Giovana G. Nunes |
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| Affiliation: | Departamento de Química, Universidade Federal do Paraná, Centro Politécnico, Jardim das Américas, , 81530‐900 Curitiba, Paraná, Brazil |
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| Abstract: | The ionic [Ti3(µ3‐OPri)2(µ‐OPri)3(OPri)6][FeCl4] halo‐alkoxide ( A ) was investigated for its activity towards the bulk polymerization of rac‐lactide (rac‐LA) and ?‐caprolactone (?‐CL) in various temperatures, monomer/ A molar proportions, and reaction times. The reactivity of A in the ring‐opening polymerization (ROP) of both monomers is mainly due to the cationic [Ti3(OPri)11]+ unity and proceeds through the coordination–insertion mechanism. Molecular weights ranging from 6,379 to 13,950 g mol?1 and PDI values varying from 1.22 to 1.52 were obtained. Results of ROP kinetic studies for both ?‐CL and rac‐LA confirm that the reaction rates are first‐order with respect to monomers. The production of poly(?‐caprolactone) shows a higher sensitivity of the reaction rate to temperature, while the polymerization of rac‐LA is slower and more dependent on the thermal stability of the active species during the propagation step. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2509–2517 |
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| Keywords: | biocompatibility cationic titanium alkoxide polyesters polynuclear ring‐opening polymerization |
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