Evolution of glassy polymers used for gas separation

A Dissertation entitled Evolution of Glassy Polymers used for Gas Separation following Ion Beam Irradiation by Jeffery B Ilconich Submitted as partial fulfillment of the requirements for Doctor of Philosophy in Engineering _ Advisor: Dr Maria Coleman _ Graduate School The University of Toledo December 2004 The University of Toledo College of Engineering I HEREBY RECOMMEND THAT THE DISSERTATION PREPARED UNDER MY SUPERVISION BY Jeffery B Ilconich ENTITLED Evolution of Glassy Polymers used for Gas Separation following Ion Beam Irradiation BE ACCEPTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN ENGINEERING Dissertation Advisor: Maria Coleman Recommendation concurred by Xinglong Xu Committee G Glenn Lipscomb Constance A Schall Song Cheng Dean, College of Engineering On Final Examination Acknowledgements This project was funded by the National Science Foundation I would like to thank The University of Toledo Chemical Engineering Department, and the Instrumentation Center Also, I appreciate that the University of Western Ontario for allowing us to use there equipment I would like to thank my advisor, Dr Maria Coleman, for all of the support she offered Also, I would like to thank Dr Xu, who had many good suggest and many answers I would like to thank my family for not allowing me to take my work to serious, and especially, Morgan, A J and Caity for always making me smile I would especially like to thank Jennifer for helping get through the difficult times and knowing that she will always be there for me An Abstract of Evolution of Glassy Polymers used for Gas Separation following Ion Beam Irradiation Jeffery B Ilconich Submitted as partial fulfillment of the requirements for Doctor of Philosophy in Engineering The University of Toledo December 2004 Commercial gas separation membranes are typically polymeric because of low cost, processibility and wide range of available properties However, while much work has been done to develop improved polymers for membranes, these materials have limitations for many applications Therefore, much work has been focused in postformation modification of polymer membrane In this work, two very different polymers were modified by ion irradiation to evaluate the evolution in chemical structure, microstructure and permeation properties A specific focus was on the impact of ion choice on properties of a specific polymer The first part of study focused on evolution in a typical commercial membrane polymer, polysulfone, following H+ irradiation Ion irradiation of polysulfone resulted in significant evolution in chemical structure at intermediate H+ doses There was a general decrease in permeance with little improvement in selectivity following irradiation Modification of asymmetric polysulfone membranes by H+ and C- irradiation resulted in significant damage to the porous substrate of the membranes Therefore, these membranes exhibited larger decreases in permeance then could be attributed to changes in the selective layer The polyimide, 6FDA-6FpDA, was irradiated with three different ions, (H+, N+ and F+) to investigate impact of ion mass and energy transfer mechanisms As expected the polymer responded different to the different ions at similar overall doses and total energy transfer In general, more damage to the polymer matrix was achieved with larger mass ions The larger relative evolution to microstructure was attributed to the greater nuclear loss mechanism for N+ and F+ relative to H+ Significant evolution in permeation properties corresponded to this change in chemical structure and microstructure While the ions exhibited similar trends in evolution in permeation properties, there were large differences in scale of modification For example, at high dose H+ irradiation, the gas pair He/CH4 exhibited significant increase in both permeance and permselectivity However, F+ irradiation at high doses exhibited drastic decreases in permeance for all gases Several irradiated samples exhibited permeation properties that were beyond the trade-off curve for tradition polymers Therefore, with additional research, ideal conditions may be selected to optimize the changes in permeation properties Table of Content Acknowledgment iii Abstract iv Table of Content vi List of Tables xi List of Figures xiv Introduction Research Objectives 3 Literature Review 3.1 Gas Separation Using Membranes 3.1.1 Polymeric Membrane Transport Characterization 3.1.2 Polymeric Membrane Materials 3.1.3 Other Membrane Materials and Processes 3.2 Ion Irradiation 10 12 3.2.1 Factors Effecting Irradiation 16 3.2.2 Ion Irradiation of Polymers 18 3.2.3 Ion Irradiation of Polymeric Membranes 19 Experimental 22 4.1 Materials 22 4.2 Membrane and Film Formation 24 4.2.1 Membranes 24 4.2.1.1 Preparation of Asymmetric PSF Membranes 24 4.2.1.2 Preparation of Composite Membranes 26 4.2.2 Dense Free-Standing Films 4.3 Ion Irradiation 26 27 4.3.1 Changing Ion Energy 29 4.3.2 Changing Ions 30 4.3.3 Normalization of Samples Modified at Different Conditions 32 4.4 Measurement of Permeance 32 4.4.1 Constant Volume/ Variable Pressure Cell 33 4.4.2 Variable Volume/ Constant Pressure Cell 34 4.5 Variable Energy Positron Annihilation Spectroscopy 35 4.6 Scanning Electronic Microscopy (SEM) 36 4.7 Fourier Transform Inferred (FTIR) Spectroscopy 37 4.8 Dissolution Analysis 37 Ion Irradiation of Polysulfone 38 5.1 Introduction 38 5.2 Results and Discussion 39 5.2.1 FTIR Analysis 39 5.3.2 Dissolution Studies 47 5.2.3 Permeation Properties of Composite Membranes 48 5.2.4 Permeation Properties of Asymmetric Membranes 52 5.2.5 Analysis of Asymmetric Membrane Microstructure 59 5.2.6 Analysis of Asymmetric Membranes 63 5.2.7 Comparison of H+ and C- Irradiated Asymmetric Membranes 70 5.4 Conclusions 71 H+ Irradiation of 6FDA-6FpDA Films and Membranes 74 6.1 Introduction 74 6.2 Results and Discussion 75 6.2.1 Dissolution and FTIR Analysis 75 6.2.2 Crosslinking Mechanism 82 6.2.3 Modification of the Microstructure 84 6.2.4 Permeation Studies 88 6.2.5 Permeance and Microstructure 91 6.4 Conclusions 6FDA-6FpDA Chemical and Microstructure Modified by Several Different Ions 95 97 7.1 Introduction 97 7.2 Results 101 7.2.1 H+ Irradiation 102 7.2.2 Impact of N+ Irradiation on Structure 104 7.2.3 Impact of F+ Irradiation on Structure 108 7.3 Discussion 111 7.3.1 Dissolution 111 7.3.2 FTIR 111 7.3.3 Ion Impact based on Energy Comparison 113 7.3.4 Dissolution 113 7.3.5 FTIR 114 7.3.6 Microstructure and Chemical Structure 116 7.3.7 Crosslinking 122 7.5 Conclusions 123 6FDA-6FpDA Permeation Evolution after Ion Irradiation by Several Different Ions 125 8.1 Introduction 125 8.2 Results 126 8.2.1 Impact of H+ Irradiation 127 8.2.2 Impact of N+ Irradiation 131 8.2.3 Impact of F+ Irradiation 134 8.2.4 Impact of Ion Dose 135 8.2.5 Energy Transfer 138 8.3 Discussion 139 8.3.1 H+ and N+ 141 8.3.2 F+ and N+ 144 8.4 Conclusions Permeability and Trade-Off Curves of Irradiated 6FDA-6FpDA Membranes 146 148 9.1 Introduction 148 9.2 Results 149 9.2.1 H+ Irradiation 149 9.2.2 N+ Irradiation 153 9.2.3 F+ Irradiation 156 9.2.4 Overall Results 161 9.3 Conclusions 10 Conclusions 161 162 11 Recommendations 164 12 Appendix 167 13 References 173 169 Table 12.5: Permeation Properties of Irradiated H+ PSF Asymmetric Membranes αO2 αCO2 α He CH Film ID Film Modification (H+/cm2) a ⎛P⎞ ⎜ ⎟ ⎝ l ⎠ O2 A B C D E 1x1013 1x1014 4x1014 8x1014 1x1015 23.0 26.3 3.9 2.8 3.6 83.7 102 15.2 10.3 14.7 164 212 54.4 52.1 57.6 4.78 3.29 3.07 1.90 2.80 20.3 12.0 19.1 9.67 17.8 39.8 25.0 68.4 48.8 70.0 F 4x1015 1.9 7.09 33.0 1.65 7.84 36.6 a a ⎛P⎞ ⎛P⎞ ⎜ ⎟ ⎜ ⎟ ⎝ l ⎠CO2 ⎝ l ⎠ He N2 CH 4 cm ( STP ) a = 1GPU = 10 − cm ⋅ s ⋅ cmHg Table 12.6: Permeation Properties of Irradiated PSF Asymmetric Membranes used for Cirradiation a a a Film Film O2 CO2 He ⎛P⎞ ⎛P⎞ ⎛P⎞ CH ID Modification ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ N2 CH ⎝ l ⎠O2 ⎝ l ⎠CO2 ⎝ l ⎠ He (C-/cm2) α α α K J L M N 4.4E+12 2.2E+13 4.4E+13 8.8E+13 1.9E+14 5.2 2.4 2.0 1.4 0.9 24.2 12.8 2.0 2.9 1.3 80.0 74.9 48.0 26.0 18.7 5.0 3.6 4.8 3.8 2.4 40.3 34.1 7.2 14.1 4.9 133.3 200.1 170.0 126.3 69.0 O P Q R 4.4E+14 1.3E+15 4.4E+13 4.4E+14 1.7 2.1 83.2 31.2 1.6 3.4 NA NA 28.6 30.0 NA NA 1.1 1.2 1.1 1.2 1.1 2.0 NA NA 19.1 17.4 NA NA a = 1GPU = 10 − cm ( STP ) cm ⋅ s ⋅ cmHg 170 Table 12.7 Virgin Permeance and Estimated Thickness of Selective layer for 6FDA-6FpDA composite Membranes αO2 αCO2 α He CH Estimated Thickness (µm) + safsadfsdfasdfsadafsdafsafaadfasasddfdsaffsadfadal H fsasdfasdfasasdfasfasdsadaddfdsasfdfasfasdfadsfasd 32.8 114.1 204.6 4.5 49.7 89.2 0.5 A 24.3 106.8 179.8 4.2 51.9 87.34 0.7 B 17.7 73.4 139.2 4.1 61.8 117.2 0.9 C 17.3 73.3 136.2 4.2 59.5 110.7 0.9 D 16.0 69.8 130.2 4.2 63.8 119.0 0.9 E + safsadfsdfasdfsadafsdafsafaadfasasddfdsaffsadfadal N fsasdfasdfasasdfasfasdsadaddfdsasfdfasfasdfadsfasd 33.8 140.9 225.3 4.5 56.1 89.7 0.5 F 19.2 110.2 168.2 4.0 55.4 84.6 0.8 G 32.8 143.2 216.8 4.4 54.2 82.1 0.5 H 12.4 46.7 119.3 3.6 38.2 97.6 1.3 I 16.1 65.4 127.6 4.9 56.3 110.0 1.1 J 44.3 160.3 270.4 4.8 47.2 79.6 0.4 K safsadfsdfasdfsadafsdafsafaadfasasddfdsaffsadfadal F+ fsasdfasdfasasdfasfasdsadaddfdsasfdfasfasdfadsfasd 7.8 33.2 52.1 3.8 45.4 71.3 2.1 L 11.8 48.6 90.3 4.6 61.9 115.0 1.4 M 13.3 48.6 91.8 4.7 35.6 67.3 1.2 N 11.4 46.6 87.7 4.5 40.9 77.0 1.4 O Film ID (Ion) a ⎛ P⎞ ⎜ ⎟ ⎝ l ⎠ O2 a ⎛P⎞ ⎜ ⎟ ⎝ l ⎠CO2 a ⎛P⎞ ⎜ ⎟ ⎝ l ⎠ He N2 CH 4 171 Table 12.8 Permeance and permselectivity for irradiated samples for 6FDA-6FpDA composite Membranes Film ID (ion type) Film Modification (ions/cm2) a ⎛P⎞ ⎜ ⎟ ⎝ l ⎠ O2 a ⎛ P⎞ ⎜ ⎟ ⎝ l ⎠CO2 a ⎛P⎞ ⎜ ⎟ ⎝ l ⎠ He αO2 N2 αCO2 CH α He CH Fadsfasdfasdfasdfdsafsadfsdafsdafsadfdsaffsadfadal H+ fsadfsadfsadfsdafasdfasdfasdfdsafsafasfasdfadsfasd A 15.1 69.6 114.4 4.3 61.5 101.0 x 1014 B 36.0 181.6 259.1 4.6 44.9 64.0 x 1015 C 27.8 119.1 191.2 6.3 83.8 134.4 x 1015 D 11.8 65.1 292.8 5.6 86.3 388.0 x 1015 E 7.2 46.2 264.7 6.0 157.8 904.3 x 1016 Fadsfasdfasdfasdfdsafsadfsdafsdafsadfdsaffsadfadal N+ fsadfsadfsadfsdafasdfasdfasdfdsafsafasfasdfadsfasd F 13.9 74.9 152.8 4.3 61.6 125.5 x 1013 G 19.4 101.2 178.2 6.1 30.2 53.1 X 1013 H 26.7 132.8 335.7 5.8 93.9 237.3 X 1014 I 18.6 76.7 208.2 5.3 50.1 136.1 X 1014 J 3.9 45.9 175.2 2.4 41.7 159.4 X 1014 K 4.6 26.3 198.7 3.2 60.5 457.3 X1015 Fadsfasdfasdfasdfdsafsadfsdafsdafsadfdsaffsadfadal F+ fsadfsadfsadfsdafasdfasdfasdfdsafsafasfasdfadsfasd L 2.8 14.6 23.1 4.0 53.3 84.5 X 1014 M 27.3 40.6 80.8 11.4 63.9 127.1 X 1014 N 1.6 17.2 35.8 2.2 53.1 110.3 X 1014 O 0.68 20.7 6.5 1.1 62.5 19.6 X 1015 a = 1GPU = 10− cm ( STP) cm ⋅ s ⋅ cmHg 172 Chapter 13 References Balanzat, E., et al., Swift heavy io irradiation of polystryene Nuclear Instruments and Methods in Physicis Research B, 1996 116: p 159 - 163 Xu, X.L.A.M., Ion beam irradiation effect on gas permeation properties of polyimide films Journal of Applied Polymer Science, 1995 55: p 99 - 105 Xu, X.L.A.M., A new approach to microporous materials - application of ion beam technology of 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