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그라프트 공중합을 이용한 비수용성 메틸셀룰로오스의 합성 및 막응용
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | 탁태문 | - |
| dc.contributor.author | 안혜련 | - |
| dc.date.accessioned | 2017-07-13T17:47:10Z | - |
| dc.date.available | 2017-07-13T17:47:10Z | - |
| dc.date.issued | 2014-02 | - |
| dc.identifier.other | 000000018342 | - |
| dc.identifier.uri | https://hdl.handle.net/10371/121134 | - |
| dc.description | 학위논문 (박사)-- 서울대학교 대학원 : 바이오시스템.소재학부(바이오소재공학전공), 2014. 2. 탁태문. | - |
| dc.description.abstract | The development of novel polymer materials with high functionality has received attention in recent decades. Among the natural polymers, cellulose and its derivatives are widely used, because they are inexpensive, most abundant, biodegradable and renewable. Methyl cellulose (MC) is a highly functional cellulose derivative with properties such as being non-ionic and having pH stability, hydrophilicity and high water retention. But since MC is water soluble, some applications are limited, for example, use as a water treatment membrane. Therefore, in this study, high functional MC-based graft copolymers were prepared by the reaction of redox system polymerization with ceric ion initiation. In order to graft the water insoluble copolymer with a soluble organic solvent, water soluble MC as a main backbone was used by changing the molar ratio of the grafted vinyl monomer without the destruction of the inherent MC properties. The various vinyl monomers such as, acrylonitrile (AN), methyl methacrylate (MMA) and styrene (ST) were grafted onto the MC backbone by ceric (IV) ion- initiated free radical polymerization in aqueous medium. Ceric (IV) ion-initiated polymerization was a useful method to obtain high molecular weight molecules. The reaction was homogeneous and the grafting percentage (%G) could be easily be controlled. The hydrophilicity, thermal stability, molecular weight, zeta-charge and mechanical strengthe were investigated using Fourier transform-infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance (1H NMR), thermogravimetric analysis (TGA), gel chromatography (GPC), zeta-potential, water contact angle and universal testing machine (UTM), respectively. The produced graft copolymers showed an improvement in thermal stability and hydrophilicity, maintaining the properties of MC. In addition these graft copolymers could be applied for antifouling water-treatment membranes. The feasibility of these copolymers as water-treatment membranes was investigated by flux, rejection and antifouling test using a dead-end filtration system. The prepared copolymer membranes showed different properties, varying by the grafted monomer. The AN graft copolymer represented remarkable antifouling properties compared with the two other grafted copolymers. | - |
| dc.description.tableofcontents | Abstract ……………………………………..…………………..…...…….. i
Table of Contents ……………………………………..…….……….……iii List of Figures ……………………………….……………..……………..vii List of Tables .………………………….………….…….….……...……. xvi 1. Introduction ……………..………...……………..… 1 2. Literature survey ……………………………..…… 5 2.1. Methyl cellulose …………………………………………….…….... 5 2.2. Graft copolymerization of cellulose polymers ……….…….….... 10 2.2.1. Free radical graft polymerization ……………………………… 13 2.2.2. The kinetics of ceric (IV) ion-initiated reaction ….…………… 21 3. Experimental ……………………………...……… 23 3.1. Materials and reagents ….…………………………..…...……. 23 3.2. Synthesis of MC-based copolymers ……………….……...….. 24 3.3. Characterizations of MC-based graft copolymers ….…...….. 28 3.4. Membrane fabrication using MC-based graft copolymers … 30 3.5. Characterization and evaluation of membranes ……………. 33 4. Results and Discussion ………...…….……..… 36 4.1. Graft reaction and structural analysis of MC-g-MMA copolymer ……………...………………………………...……. 36 4.1.1. Optimization of reaction conditions ……………………....….. 36 4.1.2. Graft yield and efficiency of MC-g-MMA copolymer …..….. 41 4.1.3. Structural analysis of MC-g-MMA copolymer …..................... 43 4.2. Graft reaction and structural analysis of MC-g-ST copolymer …………………………………..………….……...……...……. 48 4.2.1. Optimization of reaction conditions ……………………....….. 48 4.2.2. Graft yield and efficiency of MC-g-ST copolymer …….....….. 53 4.2.3. Structural analysis of MC-g-ST copolymer ….....................….. 55 4.3. Graft reaction and structural analysis of MC-g-AN copolymer …………………………………..………….……...……...……. 60 4.3.1. Optimization of reaction conditions ……………………....….. 60 4.3.2. Graft yield and efficiency of MC-g-AN copolymer …….….. 65 4.3.3. Structural analysis of MC-g-AN copolymer …...................….. 67 4.4. Properties of MC based graft copolymers …………………. 72 4.4.1. Solubility of MC-based graft copolymers ….…………............ 72 4.4.2. Effect of grafted monomer on hydrophilicity …………............ 74 4.4.3. Effect of grafted monomer on thermal stability ………............ 76 4.4.4. Performance of membranes ………………………………..…. 78 4.4.5. Effect of grafted monomer on antifouling membranes….......... 83 4.5. Effect of the %G on physical and chemical properties of MC-g- AN graft copolymer ……………………………………............. 90 4.5.1. Contact angle ………………………………….………............ 90 4.5.2. Zeta-potential …………………….…………………................ 92 4.5.3. XPS .…………………….………………….............................. 93 4.5.4. Antifouling property ......…………………………………….... 96 4.5.5. Morphological structure ……..……………………………… 105 4.5.6. Molecular weight ……...……..…………………………….. 105 4.5.7. Mechanical strength …...……..…………………………….. 106 5. Conclusion ……………………………….….. 111 6. References …………………………………… 113 List of Figures Figure 1. The chemical structure of cellulose raw material ……………………… 8 Figure 2. The etherification route from cellulose to methyl cellulose …………..… 9 Figure 3. A schematic representation of cellulose graft copolymer ……………… 11 Figure 4. A schematic representation of the grafting-from approach ………..… 12 Figure 5. The general mechanism of cellulose graft copolymerzation via ferrous reagent initiation ……………………………………………………… 18 Figure 6. The simplified mechanism of ceric (IV) ion-initiated cellulose graft copolymerization ………………………………...…………………… 19 Figure 7. Reaction mechanism of MC-based graft copolymer using ceric (IV) ion- initiation process (vinyl monomer: AN, MMA, ST)……………..…… 27 Figure 8. Scheme of dead-end membrane filtration system (Test conditions - 25°C, stirring rpm | - |
| dc.description.tableofcontents | 350-400 rpm) …………………………………………… 35
Figure 9. The relative viscosity of MC-g-MMA copolymer solution during free radical polymerization as a function of CAN concentration (HNO3: 7.5x10-2 M, MMA:10.0 x10-2 M, 25°C, 1 h) ……………………...… 38 Figure 10. The relative viscosity of MC-g-MMA copolymer solution during free radical polymerization as a function of reaction time (HNO3: 7.5x10-2 M, CAN: 15.0x10-3M, MMA: 10.0x10-2 M, 25°C) ……...………… 39 Figure 11. The relative viscosity of MC-g-MMA copolymer solution during free radical polymerization as a function of reaction temperature temperature (HNO3: 7.5x10-2 M, CAN: 15.0x10-3M, MMA: 10.0x10-2 M, 1 h) ……………………………….……………………………… 40 Figure 12. The effect of molar ratio of MMA on the percentage of grafting (HNO3:7.5x10-2 M, CAN: 15.0 x10-3M, 25°C, 1 h) ……………...… 42 Figure 13. The FT-IR transmittance spectra of base polymer MC and the MC-g-MMA copolymer (upside one: control MC, down side one: MMA grafted copolymer) ………………………………………..………… 45 Figure 14. 1H nuclear magnetic resonance peaks of base polymer MC and the MC-g-MMA copolymer (upper one: MC-g-MMA copolymer, down: MC base polymer, NMR solvent: DMF) …………………..……………… 46 Figure 15. The C 1s level of control MC and MC-g-MMA graft copolymer (X-ray source: monochromatic Al-Kα, 15 kV, 100W, 400 micrometer) ……... 47 Figure 16. The relative viscosity of MC-g-ST copolymer solution during free radical polymerization as a function of CAN concentration (HNO3: 3.5 x 10-2M, STY: 1.5 x 10-2 M,25 °C, 1h) …………………...……….…………… 50 Figure 17. The relative viscosity of MC-g-ST copolymer solution during free radical polymerization as a function of reaction time (HNO3: 3.5 x 10-2M, STY: 1.5 x 10-2 M, CAN:1.5 x 10-3, 25 °C) ….…………..…… 51 Figure 18. The relative viscosity of MC-g-ST copolymer solution during free radical polymerization as a function of reaction temperature (HNO3: 3.5 x 10-2M, STY: 1.5 x 10-2 M, CAN:1.5 x 10-3, 1h) ……...………… 52 Figure 19. The effect of molar ratio of ST on the percentage of grafting grafting (HNO3: 3.5 x 10-2M, CAN:1.5 x 10-3, 25 °C) ………..………...…… 54 Figure 20. The FT-IR spectra of control MC and MC-g-ST graft copolymer (upper one: MC backbone peak, down: MC-g-ST copolymer peak | - |
| dc.description.tableofcontents | aromatic C-C, C=C, C-H paek) …………………………………………………… 57
Figure 21. 1H nuclear magnetic resonance peaks of MC and the MC-g-ST graft copolymer (NMR solvent: DMF) …………………………………… 58 Figure 22. The XPS spectra of MC-g-ST graft copolymer (X-ray source: monochromatic Al-Kα, 15kV, 100W, 400 micrometer, no ion etching condition) ………………………………………..………………… 59 Figure 23. The relative viscosity of MC-g-AN copolymer solution during free radical polymerization as a function of reaction time (HNO3: 7.5 x 10-2 M, CAN: 7.5 x 10-3 M, AN: 60.0 x 10-2 M, 25 °C) ……………… 62 Figure 24. The relative viscosity of MC-g-AN copolymer solution during free radical polymerization as a function of CAN concentration (HNO3: 7.5 x 10-2 M, AN: 60.0 x 10-2 M, 25 °C, 1 h) …………………………… 63 Figure 25. The relative viscosity of MC-g-AN copolymer solution during free radical polymerization as a function of reaction temperature (HNO3: 7.5 x 10-2 M, CAN: 7.5 x 10-3 M, AN: 60.0 x 10-2 M, 1 h) ……...……… 64 Figure 26. The effect of molar ratio of acrylonitrile monomer on the percentage of grafting (HNO3: 7.5 x 10-2 M, CAN: 7.5 x 10-3 M, 25 °C, 1 h) …..… 66 Figure 27. The FT-IR spectra of control MC and MC-g-AN copolymer (upper : MC backbone polymer peak, down : MC-g-AN copolymer peak) ……..… 69 Figure 28. 1H NMR spectra of control MC and MC-g-AN graft copolymer (NMR solvent: DMF) ……………………………………...………………… 70 Figure 29. The XPS spectra of the control MC (a) and MC-g-AN (b) copolymer (X-ray source: monochromatic Al-Kα, 15kV, 1000W, 400 micrometer, no ionic etching ………………………………………………..………… 71 Figure 30. Contact angle images and values of MC-based graft copolymer varying on grafted monomer (AN, MMA and ST) and control PAN membrane (%G 100 copolymer, average value 5 times, measurement : 25 °C, 20 % humidity) .…...………………………………..………………… 75 Figure 31. TGA analysis of MC-based graft copolymers (MC-g-AN, MC-g-MMA, MC-g-ST) and MC …………………………………………..….……. 77 Figure 32. The PWF and rejection of MC-g-MMA graft copolymer membrane (Feed:DI water, test cell area: 28.5 cm2, 25°C, 30min level off before test) ………………………………………………………………….. 80 Figure 33. The water flux and BSA rejection of MC-g-ST copolymer membrane (Feed: DI water, 25°C, at 2 bar 30 min level off before test, BSA: 1000ppm) ………………………………………………………….... 81 Figure 34. The %G dependent PWF and BSA rejection of MC-g-AN copolymer membranes during dead-end filtration process (Feed : DI water, 1000ppm BSA, 2bar 30 min level off before test, 25°C, 20 min collect permeant) ……………………………………………………………. 82 Figure 35. Time-dependent normalized flux of MC-based copolymer membranes varying on monomer, during dead-end filtration with BSA solution (Feed: 1000ppm, 25°C, collect: every 1min for 60 min automatically) ………………………………………………………………..……… 84 Figure 36. Flux recovery ratio of MC-based copolymer membranes varying on monomer, during dead-end filtration with BSA solution (cleaning: DI water, 1 bar, 30 min) ………………………………………………… 85 Figure 37. Time-dependent normalized flux of MC-based copolymer membranes varying on monomer, during dead-end filtration with SA solution (Feed: 1000ppm, 25°C, collect: every 1min for 60 min automatically) …… 86 Figure 38. Flux recovery ratio (FRR) of MC-based copolymer membranes varying on monomer, during dead-end filtration with SA solution (cleaning: DI water, 1 bar, 30 min) ………………………………..………………… 87 Figure 39. Time-dependent normalized flux of MC-based copolymer membranes varying on monomer, during dead-end filtration with HA solution (Feed: 1000ppm, 25°C, collect: every 1min for 60 min automatically) …… 88 Figure 40. Flux recovery ratio (FRR) of MC-based copolymer membranes varying on monomer, during dead-end filtration with HA solution (cleaning: DI water, 1 bar, 30 min) ………………………………..………………… 89 Figure 41. The zeta-potential of MC-g-AN copolymer membranes varying on percentage of grafting …………………………….………………… 94 Figure 42. Time-dependent flux of MC-g-AN copolymer membranes varying on %G, during BSA filtration (Feed : 1000ppm, 25 °C, 20 % humidity, collect : every 1 min for 60 min automatically) ……………………… 97 Figure 43. Flux recovery ratio (FRR) of MC-g-AN copolymer membranes using different %G membrane filtration | - |
| dc.description.tableofcontents | BSA 1000ppm (cleaning condition : 1bar 30 min water clening, 25 °C, 20 % humidigy) …………..…….... 98
Figure 44. Time-dependent flux of MC-g-AN copolymer membranes varying on %G, during SA filtration (Feed : 1000ppm, 25 °C, 20 % humidity, collect : every 1 min for 60 min automatically) ……………………… 99 Figure 45. Flux recovery ratio (FRR) of MC-g-AN copolymer membranes using different %G membrane filtration | - |
| dc.description.tableofcontents | SA 1000ppm (cleaning condition : 1bar 30 min water clening, 25 °C, 20 % humidigy) ……………….... 100
Figure 46. Time-dependent flux of MC-g-AN copolymer membranes varying on %G, during HA filtration (Feed : 1000ppm, 25 °C, 20 % humidity, collect : every 1 min for 60 min automatically) …………………… 101 Figure 47. Flux recovery ratio (FRR) of MC-g-AN copolymer membranes using different %G membrane filtration | - |
| dc.description.tableofcontents | HA 1000ppm (cleaning condition : 1bar 30 min water clening, 25 °C, 20 % humidigy) ……………….... 102
Figure 48. Time-dependent flux of MC-g-AN copolymer membranes varying on %G, during HA filtration (Feed : 1000ppm, 25 °C, 20 % humidity, collect : every 1 min for 60 min automatically) …………………… 103 Figure 49. The flux recovery ratio (FRR) of MC-g-AN copolymer membranes using different model foulants filtration | - |
| dc.description.tableofcontents | HA, SA, BSA (cleaning condition : 1bar 30 min water clening, 25 °C, 20 % humidigy) ………..……… 104
Figure 50. The cross-section of MC-g-AN graft copolymer membranes varying on %G (a) 100 %, (b) 140 % and (c) 180 % (FE-SEM mode, gold coating) …………………………………………………………… 107 Figure 51. The molecular weight of MC-g-AN graft copolymers varying on %G (before measurement at least 4 h level off, DMF column, RI detector) …………………………………………………..………………… 108 Figure 52. The effect of %G on tensile strength of the MC-g-AN graft copolymer (test condition: 25 °C, 20 % humidity) …………………………… 109 List of Tables Table 1. The summary of monomer reactivities under various conditions ….…. 20 Table 2. The composition of the MC-based graft copolymers membrane casting solutions ……………………………………………………………… 32 Table 3. The solubility of MC-based graft copolymers .….…………………… 73 Table 4. The contact angle values of the MC-g-AN graft copolymers ………… 91 Table 5. Elemental surface composition of membranes of various %G of MC-g-AN graft copolymers …………………………………………………… 95 Table 6. The bond energy of covalent bond …………………………………… 110 | - |
| dc.format | application/pdf | - |
| dc.format.extent | 2686739 bytes | - |
| dc.format.medium | application/pdf | - |
| dc.language.iso | en | - |
| dc.publisher | 서울대학교 대학원 | - |
| dc.subject | Methyl cellulose | - |
| dc.subject | vinyl monomer | - |
| dc.subject | Acrylonitrile | - |
| dc.subject | Graft copolymer | - |
| dc.subject | Antifouling membrane. | - |
| dc.subject.ddc | 660 | - |
| dc.title | 그라프트 공중합을 이용한 비수용성 메틸셀룰로오스의 합성 및 막응용 | - |
| dc.type | Thesis | - |
| dc.description.degree | Doctor | - |
| dc.citation.pages | xvi, 126 | - |
| dc.contributor.affiliation | 농업생명과학대학 바이오시스템.소재학부(바이오소재공학전공) | - |
| dc.date.awarded | 2014-02 | - |
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