Synthesis and Thermal Properties of Novel Biodegradable ABCBA Pentablock Copolymers from Poly (Ethylene glycol), L-Lactide and p-Dioxanone

Document Type: Research Article


1 Caspian faculty of Engineering, University of Tehran, P.O. Box 43841-119 Rezvanshahr, I.R. IRAN

2 Department of Chemistry, Amirkabir University of Technology, Tehran, I.R. IRAN

3 Iran Polymer and Petrochemical Institute, Tehran, I.R. IRAN

4 Department of Chemistry, Faculty of Science, Guilan Universiry, Rasht, I.R. IRAN


In this work, new biodegradable ABCBA type pentablock copolymers with different mole ratio of L-lactide and PPDO-b-PEG-b-PPDO triblock copolymer were synthesized and characterized. In the first step, PPDO-b-PEG-b-PPDO triblock copolymer was synthesized via a ring-opening polymerization of P-DiOxanone (PDO) monomer with Poly (Ethylene Glycol) (PEG) using stannous octoate (Sn(Oct)2) as the catalyst. In the second step, L-lactide monomers (60 or 80 mole ratio) as the end blocks were added to the resulting prepolymer in presence of stannous octoate (Sn(Oct)2)  catalyst. In the first step, Poly (Ethylene Glycol) (PEG) and, in the second step, triblock copolymer acts as the macro-initiator. The obtained pentablock copolymers were identified by 1H and 13CNMR spectroscopy. Intrinsic viscosity of the resulting copolymers was measured via dilute solution viscometry in chloroform as the solvent. The thermal properties (such as melting points, melting enthalpy and crystallinity) and thermal degradation behavior were studied by Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA). From the obtained results, it was seen that the poly (L-lactide) end blocks show similar crystallization behavior like poly (L-lactide) homopolymer and also melting temperature of pentablock copolymers rise with an increase in L-lactide content.  


Main Subjects

[1] Bero M., Dobrzynski P., Kasperczyk J., Application of Zirconium (IV) Acetylacetonate to the Copolymerization of Glycolide with e-Caprolactone and Lactide, Polym. Bull., 42, p. 131 (1999).
[2] Hayashi T., Biodegradable Polymers for Biomedical Uses, Prog. Polym. Sci., 19, p. 663 (1994).
[3] Baimark Y., Molloy R.,Synthesis and Characterization of Poly (L-Lactide-co-e-caprolactone) Copolymers: Effects of Stannous Octoate Initiator and Diethylene Glycol Coinitiator Concentrations, ScienceAsia., 30, p. 327 (2004).
[4] Duda A., Biela T., Libiszowski J., Penczek S., Dubois P., Mecerreyes D., Jerome R., Block and Random Copolymers of e-Caprolactone, Polym. Degrad. Stabil., 59, p. 215 (1998).
[5] Sabino M., Gonzalez S., Marquez L., Feijoo J.L., Study of the Hydrolytic Degradation of Polydioxanone PPDX, Polym. Degrad. Stabil., 69, p. 209 (2000).
[6] Nishida H., Yamashita M., Hattori N., Endo T., Tokiwa Y., Thermal Decomposition of Poly(1,4- Dioxan-2-One), Polym. Degrad. Stabil., 70, p. 485 (2000).
[7] Hu Y., Hu Y.S., Topolkaraev V., Hiltner A., Baer E., Aging of Poly(Lactide)/Poly(Ethylene Glycol) Blends. Part 2. Poly(Lactide) with High Stereoregularity, Polymer., 44, p. 5711 (2003).
[8] Ding S.D., Wang Y.Z., Enhanced Thermal Stability of Poly (1,4-Dioxan-2-One) in Melt by Adding a Chelator, Polym. Degrad. Stabil., 91,p. 2465 (2006).
[9] Pezzin A.P.T., Duek E.A.R., Hydrolytic Degradation of Poly(Para-Dioxanone) Folms Prepared by Casting or Phase Separation, Polym. Degrad. Stabil., 78,p.405 (2002).
[10] Bhattarai N., Jiang W.Y., Kim H.Y., Lee D.R., Park S.J., Synthesis and Hydrolytic Degradation of a Random Copolymer Derived from 1,4-Dioxan-2-one and Glycolide, J. Polym. Sci. Pol. Phys., 42, p. 2558 (2004).
[11] Hony J.T., Cho N.S., Yoon H.S., Kim T.H., Lee D.H., Kim W.G., Preparation and Characterization of Biodegradable Poly(Trimethylenecarbonate-e-Caprolactone) -Block- Poly(p-Dioxanone) Copolymers, J. Polym. Sci. A1., 43,p. 2790 (2005).
[12] Bhattarai N., Kim H.Y., Cha D.I., Lee D.R., Yoo D.I., Nonisothermal Crystallization and Melting Behavior of the Copolymer Derived from p-Dioxanone and Poly(ethylene Glycol), Eur. Polym. J., 39, p. 1365 (2003).
[13] Wang H., Dong J.H., Qiu K.Y., Gu Z.W., Synthesis of PDON-b-PEG-b-PDON Block Copolymers and Drug Delivery System Therefor, J. Appl. Polym. Sci., 68, p. 2121 (1998).
[14] Yang K.K., Zhang L., Wang Y.Z., Zeng J.B., Wang X.L., Chen S.C., Zeng Q., Li B., ABA Triblock Copolymers from Poly(p-Dioxanone) and Poly(Ethylene Glycol), J. Appl. Polym. Sci., 102, p. 1092 (2006).
[15] Bhattarai N., Kim H.Y., Lee D.R., Thermogravimetric Study of Copolymers Derived from p-Dioxanone, 1-Lactide and Poly(Ethylene Glycol), Polym. Degrad. Stabil., 78, p. 423 (2002).
[16] Bhattarai N., Bhattarai S.R., Khil M.S., Lee D.R., Kim H.Y., Aqueous Solution Properties of Amphiphilic Triblock Copolymer Poly(p-Dioxanone-co-L-Lactide)-Black-Poly(Ethylene Glycol), Eur. Polym. J., 39, p. 1603 (2003).
[17] Bhattarai N., Kim H.Y., Lee D.R., Park S.J., Synthesis and Characterization of ABAType Tri-Block Copolymers Derived from P-Dioxanone, L-Lactide and Poly(Ethylene Glycol), Polym. Int., 52, p. 6 (2003).
[18] Keese R., Muller R.K., Toube T.P., "Fundamentals of Preparative Organic Chemistry", John Wiley & Sons,New York(1982).
[19] Gilding D.K., Reed A.M., Biodegradable Polymers for Use in Surgery-Polyglycolic/Poly(Lactic Acid) Homo- and Copolymers, Polymer., 20, p. 1459 (1979).
[20] Du Y.J., Lemstra P.J., Nijenhuis A.J., Van Aert H.A.M., Bastiaansen, C., ABA Type Copolymers of Lactide with Poly(Ethylene Glycol), Kinetic, Mechanistic, and Model Studies, Macromolecules., 28, p. 2124 (1995).
[21] Han  D.K., Hubbell J.A.,Lactide-Based Poly(Ethylene Glycol) Polymer Networks for Scaffolds in Tissue Engineering, Macromolecules., 29, p. 5233 (1996).
[22] Zhu  K.J. Lin X.Z.,Yang  S.L., Preparation, Characterization and Properties of Polylactide (PLA)- Ply(Ethylene Glycol) (PEG) Copolymers:A Potential Drug Carrier, J. Appl. Polym. Sci., 39,p. 1 (1990).
[23] RashkovI., Manolova N., Li S.M., Espartero J.L., Vert M., Synthesis, Characterization and Hydrolytic Degradation of PLA/PEO/PLA Triblock Copolymers with Short Poly (L-Lactic Acid) Chains, Macromolecules., 29, p. 50 (1996).
[24] Li S.M., Rashkov I., Espartero J.L., Manolova N., Vert M., Sy  nthesis, Characterization and Hydrolytic Degradation of PLA/PEO/PLA Triblock Copolymers with Long Poly(L-Lactic Acid) Blocks, Macromolecules., 29, p. 57 (1996).