Catalytic Synthesis and Characterization of Biodegradable ...

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Chapter 1 1.5.1.2 Polypyrrole (PPy) Among conducting polymers, polypyrrole is especially promising for commercial applications because of its good environmental stability, facile synthesis, and higher conductivity than many other conducting polymers (Figure 1.5.1B). PPy can be easily prepared by either a chemical or electrochemical polymerization of pyrrole. However, the synthetically conductive PPy is insoluble and infusible. To improve the processibility, many approaches have been developed. For example, several kinds of soluble PPy have been synthesized, such as poly (3-alkylpyrrole) with an alkyl group equal to or greater than a butyl group. 102 Poly (3-alkylpyrrole) is easily soluble in common solvents or soluble in water when the substituents bear hydrophilic groups, such as –SOH3. However, poly (N-substituted pyrroles) has much lower conductivity due to greatly suppressed conjugation along the 103, 104 polymer chains by the substituents on nitrogen. 1.5.1.3 Poly(thiophene) (PT) Like polypyrrole, poly(thiophene) is also an important poly(heterocyc1es) (Figure 1.5.1C). From a theoretical viewpoint, PT has been often considered as a model for the study of charge transport in conductive polymers with a nondegenerate ground state, while on the other hand, the high environmental stability of both its doped and undoped states has led to its wide applications. 105 PT is essentially prepared by means of two main routes: the chemical and the electrochemical syntheses. Although it is likely that chemical syntheses are the most adequate methods to prepare oligomers with defined structure, until now, the most extensively conjugated and most conductive PT have been prepared by electrochemical polymerization. Unsubstituted PT is conductive after doping, but is intractable and soluble only in solutions like mixtures of arsenic trifluoride and arsenic pentafluoride. 106 However, examples of organic-soluble PT were reported when it was substituted. Nickel-catalyzed Grignard cross-coupling was used to synthesize two soluble PTs, poly(3-butylthiophene) and poly(3-methylthiophene-co-3'-octylthiophene), which could be cast into films and doped with iodine to reach conductivities of 4 to 6 S/cm. 107 Hotta et al. synthesized poly(3-butylthiophene) and poly(3-hexylthiophene) electrochemically 108 , and characterized the polymers in solution and cast into films. 109 The soluble PATs demonstrated both thermochromism and solvatochromism in chloroform and 2,5-dimethyltetrahydrofuran. 110 ‐ 20 ‐
1.5.1.4 Polyaniline (PANi) - 21 - Polymerization and Applications of Biodegradable Polyesters Polyaniline is an intrinsically conducting polymer consisting of phenyldiamine and quinodiimine units, the general formula can be shown as Figure 1.5.2. Polyaniline is widely studied due to its ease of synthesis, environmental stability, and simple doping/dedoping chemistry. The synthesis approaches of PANi were various but the most common method was based on mixing aqueous solutions of aniline hydrochloride and ammonium peroxydisulfate at room temperature, followed by the separation of PANi hydrochloride precipitate by filtration and drying. 111 Electrochemical synthesis is also a common alternative for preparing PANi, particularly because this synthetic procedure is relatively straightforward. It was found that the structure of PANi and its physical and chemical properties strongly dependent on their preparation and doping methods. Therefore, to explore new synthesis and doping method is necessary to expand the application extent of PANi. In recent years, a number of novel polymerization methods were developed, such as emulsion polymerization, microemulsion polymerization and template polymerization. 112 Figure 1.5.2 Structure of polyaniline. 1.5.2 Electroactive Polymers for Biomedical Applications Electroactive polymers have been widely applied in the microelectronics industry, including battery technology, light emitting, diodes photovoltaic devices, and electrochromic displays. 113 Based on the concept that cellular activities can be influenced by electricity, electroactive polymers were found to be unique in modulating of the cell adhesion, migration, DNA synthesis, and protein secretion. 114-118 Most of the researches focused on the tissues or cells which respond to electrical impulses, including nerve, muscle, bone, and cardiac cells. Besides the ability of transferring charge from a biochemical reaction, most of electroactive polymers such as PPy and PT are biocompatible, which is an important property of biomaterials. These unique characteristics made them useful in many biomedical applications, such as tissue engineering materials, biosensors, drug delivery devices and bioactuators.
Page 1 and 2: Catalytic Synthesis and Characteriz
Page 3 and 4: Preface Biodegradable polyesters ha
Page 5 and 6: Chapter 3 Polymerization of Lactic
Page 7 and 8: Chapter 1 Polymerization and Applic
Page 9 and 10: - 3 - Polymerization and Applicatio
Page 13 and 14: 1.2.2 Aluminum Catalysts - 7 - Poly
Page 17 and 18: 1.3 Polylactide 1.3.1 Introduction
Page 19 and 20: - 13 - Polymerization and Applicati
Page 21 and 22: 1.3.4 Application of PLA Figure 1.3
Page 25: - 19 - Polymerization and Applicati
Page 47 and 48: 1.6.1 Radical Polymers for Organic
Page 51 and 52: initialization of the device by app
Page 55 and 56: 1.6.2.4 Others - 49 - Polymerizatio
Page 63 and 64: 182. R. B. Weller, J. Invest. Derma
Page 65 and 66: Chapter 2 Synthesis and Electrochem
Page 67 and 68: Synthesis and Electrochemistry of S
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Synthesis and Electrochemistry of S
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Synthesis and Electrochemistry of S
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Chapter 3 3.1 Introduction Poly(lac
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Chapter 3 polydispersity index (PDI
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Chapter 3 aluminum based complexes
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Chapter 3 3.5 Conclusions Co(III) c
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Chapter 3 22. Z. H. Tang, X. S. Che
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Chapter 4 4.1 Introduction Stimulus
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Chapter 4 the proton of methenyl gr
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Chapter 4 attributed to the amide g
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Chapter 4 4.4 Thermal Properties Th
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Chapter 4 Figure 4.8 MTT assay for
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Chapter 4 The 1 H NMR and 13 C NMR
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Chapter 4 Cell viability (%) = (Asa
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Chapter 5 Synthesis of Triblock Cop
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5.2 Synthesis of Triblock Copolymer
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Sample Table 1. Feed and result com
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= 25 μm. B: MTT assay for the cyto
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‐ 109 ‐ Synthesis of Triblock C
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‐ 111 ‐ Synthesis of Triblock C
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Chapter 6 6.1 Introduction Since th
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Chapter 6 6.3 Synthesis of MPEG-b-P
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Chapter 6 used to characterize the
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Chapter 6 Figure 6.6 Cyclic voltamm
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Chapter 6 vivo cytotoxicity was als
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Chapter 6 NMR. Characterization of
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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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