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Chapter 3 3.5 Conclusions Co(III) complexes with Schiff base ligands and Tin(II) alphatates were found to be the catalysts for the ROP of LacOCA to produce poly(lactic acid). Intra- and/or inter-transesterification were suggested to coincide with the polymerization, which resulted in a relatively large polydispersity. The carbonyldioxy group was eliminated from the polymerization system. The corresponding PLA showed similar Tg but lower T5% compared with PLA obtained from lactides, as a result of the lower molecular weights. Al(III) complexes with Schiff base ligands were not catalytically active for the polymerization of LacOCA. 3.6 Experimental Section General Procedures LacOCA and Co(III) complexes with Schiff base ligands (Figure 3.2) were prepared according to the already published procedures. 33, 34 Toluene was dried by distillation over sodium under the protection of nitrogen. 1 H NMR spectra were recorded on Bruker AV 300 MHz, Bruker AV 400 MHz or Bruker AV 600 MHz spectrometer in CDCl3 at 25ºC. Chemical shifts were referenced to tetramethylsilane (TMS) for the 1 H NMR measurement. Gel permeation chromatography (GPC) was performed in THF (Flow rate 1.00 ml/min at 35ºC) on a Waters 410 GPC. The columns were calibrated against polystyrene (PS) as the external standard. Differential scanning calorimetry (DSC) analyses were carried out at a heating rate of 10 °C/min on a Perkin Elmer Instruments DSC-7. Polymerization of LacOCA All of the procedures were carried out under the protection of dry argon. In a typical procedure, LacOCA (2.92 mmol, 0.34 g), 2-propanol (0.029 mmol, in 0.34 mL of toluene), Co(III)-c-(NO2)2 (0.029 mmol, 0.0258g), and toluene (5.5 mL) were added to a dried ampoule equipped with a magnetic stirrer bar. The initial concentration of LacOCA monomer in toluene was 0.5 mol/mL. The ampoule was placed in an oil bath at 70 °C. After polymerization, the polymer was dissolved in chloroform and isolated by precipitation into cold ethanol, which was collected by filtration and dried under vacuum at room temperature for 24h. ‐ 82 ‐
References Polymerization of Lactic O‐Carboxylic Anhydride using Organometallic Catalysts 1. H. R. Kricheldorf, M. Berl, N. Scharnagl, Macromolecules 1988, 21, 286. 2. C. G. Pitt, M. M. Gratzl, G. L. Kimmel, J. Surles, A. Schindler, Biomaterials 1981, 2, 215. 3. K. J. L. Burg, S. Porter, J. F. Kellam, Biomaterials 2000, 21, 2347. 4. J. P. Penning, H. Dijkstra, A. J. Pennings, Polymer 1993, 34, 942. 5. R. Bodmeier, K. H. Oh, Chen, H. Int. J. Pharm. 1989, 51, 1. 6. H. Ohara, U. Doi, M. Otsuka, H. Okuyama, S. Okada, Seibutsu-Kogaku Kaishi-J. Soc. Ferment. Bioeng. 2001, 79, 142. 7. J. Zhang, P. Krishnamachari, J. Z. Lou, A. Shahbazi, In Proceedings of the 2007 National Conference on Environmental Science and Technology, Uzochukwu, G. A., Ed. Springer: New York, 2009; pp 3-8. 8. G. Schwach, J. Coudane, R. Engel, M. Vert, Biomaterials 2002, 23, 993. 9. L. Tang, L. Deng, J. Am. Chem. Soc. 2002, 124, 2870. 10. O. T. Du Boullay, E. Marchal, B. Martin-Vaca, F. P. Cossio, D. Bourissou, J. Am. Chem. Soc. 2006, 128, 16442. 11. C. Bonduelle, B. Martin-Vaca, F. P. Cossio, D. Bourissou, Chem. Eur. J. 2008, 14, 5304. 12. C. Bonduelle, B. Martin-Vaca, D. Bourissou, Biomacromolecules 2009, 10, 3069. 13. X. Pang, H. Z. Du, X. S. Chen, X. H. Wang, X. B. Jing, Chem. Eur. J. 2008, 14, 3126. 14. H. Z. Du, X. Pang, H. Y. Yu, X. L. Zhuang, X. S. Chen, D. M. Cui, X. H. Wang, X. B. Jing, Macromolecules 2007, 40, 1904. 15. Z. H. Tang, V. C. Gibson, Eur. Polym. J. 2007, 43, 150. 16. X. Pang, H. Z. Du, X. S. Chen, X. L. Zhuang, D. M. Cui, X. B. Jing, J. Polym. Sci., Part A: Polym. Chem. 2005, 43, 6605. 17. Z. H. Tang, Y. K. Yang, X. Pang, J. L. Hu, X. S. Chen, N. H. Hu, X. B. Jing, J. Appl. Polym. Sci. 2005, 98, 102. 18. A. Kowalski, A. Duda, S. Penczek, Macromolecules 1998, 31, 2114. 19. B. M. Chamberlain, M. Cheng, D. R. Moore, T. M. Ovitt, E. B. Lobkovsky, G. W. Coates, J. Am. Chem. Soc. 2001, 123, 3229. 20. L. H. Piao, Z. L. Dai, M. X. Deng, X. S. Chen, X. B. Jing, Polymer 2003, 44, 2025. 21. Z. Y. Zhong, P. J. Dijkstra, C. Birg, M. Westerhausen, J. Feijen, Macromolecules 2001, 34, 3863. ‐ 83 ‐
Page 1 and 2:
Catalytic Synthesis and Characteriz
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Preface Biodegradable polyesters ha
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Chapter 3 Polymerization of Lactic
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Chapter 1 Polymerization and Applic
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- 3 - Polymerization and Applicatio
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1.2.2 Aluminum Catalysts - 7 - Poly
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1.3 Polylactide 1.3.1 Introduction
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- 13 - Polymerization and Applicati
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1.3.4 Application of PLA Figure 1.3
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1.5.1.4 Polyaniline (PANi) - 21 - P
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Page 65 and 66: Chapter 2 Synthesis and Electrochem
Page 67 and 68: Synthesis and Electrochemistry of S
Page 79: Synthesis and Electrochemistry of S
Page 84 and 85: Chapter 3 3.1 Introduction Poly(lac
Page 86 and 87: Chapter 3 polydispersity index (PDI
Page 88 and 89: Chapter 3 aluminum based complexes
Page 92 and 93: Chapter 3 22. Z. H. Tang, X. S. Che
Page 94 and 95: Chapter 4 4.1 Introduction Stimulus
Page 96 and 97: Chapter 4 the proton of methenyl gr
Page 98 and 99: Chapter 4 attributed to the amide g
Page 100 and 101: Chapter 4 4.4 Thermal Properties Th
Page 102 and 103: Chapter 4 Figure 4.8 MTT assay for
Page 104 and 105: Chapter 4 The 1 H NMR and 13 C NMR
Page 106 and 107: Chapter 4 Cell viability (%) = (Asa
Page 109 and 110: Chapter 5 Synthesis of Triblock Cop
Page 111 and 112: 5.2 Synthesis of Triblock Copolymer
Page 113 and 114: Sample Table 1. Feed and result com
Page 115 and 116: = 25 μm. B: MTT assay for the cyto
Page 117 and 118: ‐ 109 ‐ Synthesis of Triblock C
Page 119: ‐ 111 ‐ Synthesis of Triblock C
Page 124 and 125: Chapter 6 6.1 Introduction Since th
Page 126 and 127: Chapter 6 6.3 Synthesis of MPEG-b-P
Page 128 and 129: Chapter 6 used to characterize the
Page 130 and 131: Chapter 6 Figure 6.6 Cyclic voltamm
Page 132 and 133: Chapter 6 vivo cytotoxicity was als
Page 134 and 135: Chapter 6 NMR. Characterization of
Page 136 and 137: Chapter 6 CO2 for 24 h. RSC96 cells
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Chapter 7 Conclusion and Future Pro
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‐ 131 ‐ Conclusion and Future P
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‐ 133 ‐ Conclusion and Future P
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13. Xuan Pang, Xuesi Chen, Xiuli Zh
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Acknowledgments The present thesis
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