Synthesis, Characterization, and Gas Permeation Properties

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Perfluoroacylation of Ethyl Cellulose CH4 were also revealed. Experimental Section Measurements. Infrared spectra were recorded on a Jasco FTIR-4100 spectrophotometer. The number- and weight-average molecular weights (Mn and Mw, respectively) and polydispersity indices (Mw/Mn) of polymers were determined by size-exclusion chromatography (SEC) at 40 ºC with a Jasco PU-980/RI-930 and Viscotek UV/LS-T60A chromatograph (eluent THF, column TSK-GEL GMHXL (Tosoh), molecular weight range up to 4×10 8 , flow rate 1 mL/min). Elemental analyses were performed at the Microanalytical Center of Kyoto University. Thermogravimetric analyses (TGA) were conducted in air with a Perkin-Elmer TGA7 thermal analyzer by heating the samples (3–5 mg) from 100–700 ºC at a scanning rate of 10 ºC min -1 . Differential scanning calorimetric (DSC) analyses were performed using a Seiko DSC6200/EXSTAR6000 apparatus and measurements were carried out by making use of 3–5 mg samples, under a nitrogen atmosphere, after calibration with an indium standard. The samples were first heated from ambient temperature (25 ºC) to +200 °C at a scanning rate of 20 ºC min -1 (first heating scan) and then immediately quenched to -50 °C at a rate of about 80 ºC min -1 . The second heating scans were run from -50 to +200 °C at a scanning rate of 20 ºC min -1 to record stable thermograms. The data for glass transition temperature (Tg), cold crystallization temperature (Tcc), and melting temperature (Tm), were all obtained from the second run and correspond to the midpoint of discontinuity in the heat flow. The static contact angle (CA) of water with polymer membranes was determined by the sessile-drop method using a Kyowa Interface Science CA-X contact angle meter at room temperature. A droplet of water (10 μL) was placed on a specimen for 30 s and then the contact angle was recorded. The measurement was repeated at ten different positions on the same specimen and the data were averaged. Membrane thickness was estimated by using a Mitutoyo micrometer. The gas permeability coefficients (P) were measured with a Rikaseiki K-315-N gas permeability apparatus using a 54
55 Chapter 2 constant volume/variable-pressure system. All of the measurements were carried out at 25 ºC and a feed pressure of 0.1 MPa (1 atm) while the system was being evacuated on the downstream side of the membrane. Materials. Ethyl cellulose (1; ethoxy content, 49 wt%) and imidazole were purchased from Aldrich and Wako (Japan), respectively, and used as received. Trifluoroacetic anhydride, heptafluorobutanoyl chloride, pentafluorobenzoyl chloride (Aldrich), pentafluoropropionic anhydride (Tokyo Kasei, Japan), and pentadecafluorooctanoyl chloride (Wako, Japan) were obtained commercially and used without further purification. Tetrahydrofuran (THF), used as reaction solvent, was purchased from Wako (Japan) and employed after distillation. Perfluoroacylated derivatives of ethyl cellulose (2a–e) were synthesized according to Scheme 1. The details of the synthetic procedure and analytical data are as follows: Trifluoroacetyl Derivative of Ethyl Cellulose (2a). A 200 mL one-necked flask was equipped with a dropping funnel, a three-way stopcock, and a magnetic stirring bar. Ethyl cellulose, 1, (1.43 g, 6.10 mmol) and imidazole (0.83 g, 12.2 mmol) were placed in the flask, evacuated for half an hour, flushed with nitrogen, and dissolved in THF (50 mL) at room temperature. Then, trifluoroacetic anhydride (0.85 mL, 6.10 mmol) was added dropwise and stirring was continued for 24 h at room temperature. Product was isolated by precipitation in methanol (1000 mL), filtered with a membrane filter, washed repeatedly with methanol, and dried under vacuum to constant weight to afford the desired product (91%) as white solid. IR (ATR, cm -1 ): 2974, 2870, 1794, 1375, 1220, 1090, 1050, 920, 880, 770, 736. Pentafluoropropanoyl Derivative of Ethyl Cellulose (2b). This derivative was prepared by following the same procedure as for 2a using pentafluoropropionic anhydride (1.21 mL) instead of trifluoroacetic anhydride. Yield 93%, white solid, IR (ATR, cm -1 ): 2974, 2872, 1789, 1376, 1354, 1221, 1090, 1049, 1027, 920, 883, 839, 739. Heptafluorobutanoyl Derivative of Ethyl Cellulose (2c). This derivative
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Synthesis, Characterization, and Ga
Page 3 and 4:
Table of Contents General Introduct
Page 5 and 6: General Introduction cellulose deri
Page 7 and 8: General Introduction biogenetically
Page 9 and 10: General Introduction chemistry offe
Page 11 and 12: General Introduction solution-diffu
Page 13 and 14: General Introduction A simplified t
Page 15 and 16: General Introduction been observed
Page 17 and 18: polymers. 41,46 General Introductio
Page 19 and 20: General Introduction Keeping in vie
Page 21 and 22: General Introduction the derivatize
Page 23 and 24: General Introduction strategy (G1-a
Page 25 and 26: General Introduction In conclusion,
Page 27 and 28: General Introduction 5. (a) Kobayas
Page 29 and 30: General Introduction 15. (a) Goetma
Page 31 and 32: General Introduction American Chemi
Page 33 and 34: General Introduction Macromolecules
Page 35 and 36: Silylation of Ethyl Cellulose Intro
Page 37 and 38: Silylation of Ethyl Cellulose milli
Page 39 and 40: Silylation of Ethyl Cellulose chlor
Page 41 and 42: Silylation of Ethyl Cellulose Resul
Page 43 and 44: Silylation of Ethyl Cellulose Solub
Page 45 and 46: Silylation of Ethyl Cellulose 1.034
Page 47 and 48: Silylation of Ethyl Cellulose poly(
Page 49 and 50: Silylation of Ethyl Cellulose the r
Page 51 and 52: Silylation of Ethyl Cellulose D.; Y
Page 53 and 54: Chapter 2 51 Chapter 2 Synthesis, C
Page 55: 53 Chapter 2 are few and far betwee
Page 59 and 60: 57 Chapter 2 Membrane Density. Memb
Page 61 and 62: 59 Chapter 2 IR spectrum of 1 (Figu
Page 63 and 64: 61 Chapter 2 1,3-bis(trifluoromethy
Page 65 and 66: 63 Chapter 2 The increase in the po
Page 67 and 68: 65 Chapter 2 other fluorinated poly
Page 69 and 70: 67 Chapter 2 of the gas permeabilit
Page 71 and 72: 69 Chapter 2 Gas Diffusivity and So
Page 73 and 74: 71 Chapter 2 mobility of the perflu
Page 75 and 76: 73 Chapter 2 1325-1329. (b) Hamza,
Page 77 and 78: Chapter 3 75 Chapter 3 Synthesis an
Page 79 and 80: 77 Chapter 3 cost, and above all ap
Page 81 and 82: 79 Chapter 3 molecular weights (Mn
Page 83 and 84: 81 Chapter 3 1.99-2.07 (m, 2H, (CH3
Page 85 and 86: 83 Chapter 3 25 °C, ppm): 11.9, 13
Page 87 and 88: 85 Chapter 3 38.1, 44.7, 46.8, 47.9
Page 89 and 90: 87 Chapter 3 CH2CH2C(=O)O), 2.50-4.
Page 91 and 92: 89 Chapter 3 1091, 1053, 853, 806,
Page 93 and 94: 91 Chapter 3 dendrons (G1-a-ІІ-G1
Page 95 and 96: 93 Chapter 3 (DMAP) as a base, as s
Page 97 and 98: Figure 3. FTIR spectra of 1, 2c, an
Page 99 and 100: 97 Chapter 3 (partly soluble) and 3
Page 101 and 102: 99 Chapter 3 increased polarity of
Page 103 and 104: 101 Chapter 3 that of 1, and approx
Page 105 and 106: 103 Chapter 3 derivatization per th
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105 Chapter 3 (2a-c) were in the or
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107 Chapter 3 2709-2719. (b) Schenn
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109 Chapter 3 17. van Krevelen, D.
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Chapter 4 111 Chapter 4 Synthesis,
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113 Chapter 4 Since, no significant
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115 Chapter 4 Materials. Ethyl cell
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DStotal = DSEt + DSCarb (for 1a and
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119 Chapter 4 Figure 2. 1 H NMR spe
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121 Chapter 4 ruling out the possib
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123 Chapter 4 t-butyl moiety. A str
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125 Chapter 4 reported to lead to t
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127 Chapter 4 Table 4. Gas Permeabi
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129 Chapter 4 augmentation in eithe
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131 Chapter 4 indicate the signific
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133 Chapter 4 M.-R. J. Appl. Polym.
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Chapter 5 135 Chapter5 Synthesis an
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137 Chapter5 acid- and peptide-cont
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139 Chapter5 Specific rotations ([
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141 Chapter5 1.66 (brs, 1.1H, NHCH(
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143 Chapter5 as shown in Scheme 1,
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145 Chapter5 in Table 1. The molecu
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147 Chapter5 almost same pattern of
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Conclusions Table 3. Thermal Proper
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151 Chapter5 W.; Jing, X. J. Polym.
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Chapter 5 Synthesis and Properties
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Acknowledgments While submitting th
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Synthesis, Characterization, and Ga
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