Catalytic Synthesis and Characterization of Biodegradable ...

More documents

Recommendations

Info

Chapter 4 4.4 Thermal Properties The DSC thermograms of the PTAm homopolymer, PLA-HEMA and PTAm-g-PLA2 were recorded and shown in Figure 4.6A. PTAm showed no thermal transition at temperatures above 20 o C. The melting temperature Tm of PLA-HEMA was low, around 133 o C, due to its low molecular weight. For PTAm-g-PLA copolymer, no Tg or Tm was observed in the tested temperature ranges, which may be ascribed to the low PLA content in the copolymer. The TGA curves of the PTAm homopolymer, PLA-HEMA and PTAm-g-PLA also demonstrated that the copolymers had similar thermal properties with that of PTAm (Figure 4.6B). Figure 4.6 (A) DSC traces of the PLA-HEMA, PTAm, and PTAm-g-PLA2 in second heating. (B) TGA curves of PLA-HEMA, PTAm, and PTAm-g-PLA. 4.5 Phase Separation Behavior of PTAm-g-PLA The phase behavior of the PTAm-g-PLA copolymer is very important to its application. Therefore, the phase images of blend of PTAm and PLA, blend of PLA and PTAm-g-PLA2, PTAm-g-PLA2 and PTAm-g-PLA1 films cast from their chloroform solutions were examined by AFM (Figure 4.7). It was observed in Figure 4.7B and 4.7C that the film of copolymer exhibited two different phases. One was continuous and another phase was uniformly dispersed in the film. Considering the low PLA content in PTAm-g-PLA2 and PTAm-g-PLA1, it can be safely concluded that the continuous phase was PTAm. This unique phase behavior can probably be attributed to the immiscible nature of PTAm and PLA as shown in Figure 4.7A. It had been demonstrated that the incorporation of two immiscible chains into one copolymer prevented the macro-phase separation of these incompatible materials, which can restrict the partition of the components to nanoscopic (1-100 nm) domains. 23 As shown in ‐ 92 ‐
‐ 93 ‐ Synthesis of Lactide‐Grafted Poly(TEMPO‐acrylamide) and its Electrochemical Property and Biocompatibility Figure 4.7D, the blend film of PLA and PTAm-g-PLA2 also exhibited phase separation but the dispersion of PLA was more uniform, indicating that PTAm-g-PLA acted as a compatibilizer which modified the PLA and PTAm interface. 4.6 Cytotoxicity of PTAm-g-PLA To determine the cytotoxicity of the PTAm-g-PLA copolymer in comparison with PLA and PTAm, the MTT assay by the RSC96 cell line was conducted, and the results were shown in Figure 4.8. The copolymers exhibited similar cytocompatibility as compared to the PTAm homopolymer. This is mainly attributed to the reason that all the polymers tested are hydrophobic and no cytotoxic small organic molecules or polymers were dissolved during the extraction process. Figure 4.7 AFM Phase image: blend of PLA and PTAm with a weight ratio of 1:4 (A); PTAm-g-PLA2 (B), PTAm-g-PLA1(C), and blend of PLA and PTAm-g-PLA2 with a weight ratio of 1:4 (D).
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 11 and 12:
Page 13 and 14:
1.2.2 Aluminum Catalysts - 7 - Poly
Page 15 and 16:
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 23 and 24:
Page 25 and 26:
Page 27 and 28:
1.5.1.4 Polyaniline (PANi) - 21 - P
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
1.6.1 Radical Polymers for Organic
Page 49 and 50: - 43 - Polymerization and Applicati
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
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 90 and 91: Chapter 3 3.5 Conclusions Co(III) c
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 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
Page 141 and 142: Chapter 7 Conclusion and Future Pro
Page 143 and 144: ‐ 131 ‐ Conclusion and Future P
Page 145 and 146: ‐ 133 ‐ Conclusion and Future P
Page 147 and 148: 13. Xuan Pang, Xuesi Chen, Xiuli Zh
Page 149: Acknowledgments The present thesis
show all

Catalytic Synthesis and Characterization of Biodegradable ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?