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Raheem H, Craster B, Seshia A. Analysis of Permeation and Diffusion Coefficients to Infer Aging Attributes in Polymers Subjected to Supercritical CO2 and H2 Gas at High Pressures. Polymers (Basel) 2022; 14:polym14183741. [PMID: 36145885 PMCID: PMC9502564 DOI: 10.3390/polym14183741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/23/2022] [Accepted: 08/26/2022] [Indexed: 11/29/2022] Open
Abstract
There is a need to understand the permeation flux behavior of polymers exposed to high-pressure and -temperature fluids continuously for long time intervals. This study investigates evidence of structural alterations in polymer specimens as indicators of material aging through the monitoring of transport coefficients at pressure steps from 10 barg to 400 barg and temperatures ranging between 30 °C and 90 °C. The continuous flow permeation methodology is a well-established technique described in the literature for applications from membrane separation processes to polymeric pressure barriers used for complex fluid containment in the oil and gas industry. In this study, a novel methodology has been used that allows the permeating flux of supercritical CO2 and H2 gas through raised-temperature polyethylene and polyvinylidene fluoride films at varying elevated temperatures and pressures to be determined, over timescales of several months using gas chromatography. During these long-term measurements, changes in the test conditions, principally in temperature and stepwise increases in differential gas pressure, were made in order to determine the activation energy for permeation along with the transport coefficients of permeation, diffusion, and sorption. At no time was the polymer film allowed to outgas during the temperature or pressure alterations. The permeation experiments are complemented by differential scanning calorimetry tests to track changes in polymer crystallinity before and after exposure of the specimen to plasticizing gases, which revealed the extent of structural alterations inflicted on the specimen due to high temperature and pressure loads. It is seen that specimens that were exposed to starting high pressures aged more than those that had gradual increases in feed pressure. Furthermore, the relationship between transport coefficients and fractional free volume in the polymer upon exposure to high pressure and temperature conditions is explored. Lastly, the benefit of using fugacity in place of feed pressure for the calculation of the permeability coefficient is discussed. This study contributes to the understanding of the effect of prolonged exposure of the polymeric specimens to CO2 and H2 gas under stepwise pressure and temperature loading on their flux behaviors and crystallinity, and to candidate polyethylene-based specimens for oil field deployment.
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Affiliation(s)
- Hamad Raheem
- Department of Engineering, University of Cambridge, Trumpington St., Cambridge CB2 1PZ, UK
- Correspondence: (H.R.); (B.C.)
| | - Bernadette Craster
- Materials and Structural Integrity, TWI Ltd., Granta Park, Cambridge CB21 6AL, UK
- Correspondence: (H.R.); (B.C.)
| | - Ashwin Seshia
- Department of Engineering, University of Cambridge, Trumpington St., Cambridge CB2 1PZ, UK
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Kiran E, Sarver JA, Hassler JC. Solubility and Diffusivity of CO2 and N2 in Polymers and Polymer Swelling, Glass Transition, Melting, and Crystallization at High Pressure. A Critical Review and Perspectives on Experimental Methods, Data, and Modeling. J Supercrit Fluids 2021. [DOI: 10.1016/j.supflu.2021.105378] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Khalid HU, Ismail MC, Nosbi N. Permeation Damage of Polymer Liner in Oil and Gas Pipelines: A Review. Polymers (Basel) 2020; 12:polym12102307. [PMID: 33050120 PMCID: PMC7601364 DOI: 10.3390/polym12102307] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 11/23/2022] Open
Abstract
Non-metallic pipe (NMP) materials are used as an internal lining and standalone pipes in the oil and gas industry, constituting an emerging corrosion strategy. The NMP materials are inherently susceptible to gradual damage due to creep, fatigue, permeation, processing defects, and installation blunder. In the presence of acid gases (CO2, H2S), and hydrocarbons under high pressure and temperature, the main damage is due to permeation. The monitoring of possible damage due to permeation is not well defined, which leads to uncertainty in asset integrity management. Assessment of permeation damage is currently performed through mechanical, thermal, chemical, and structural properties, employing Tensile Test, Differential Scanning Calorimetry (DSC), Fourier-transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM)/Transmission Electron Microscopy (TEM), to evaluate the change in tensile strength, elongation, weight loss or gain, crystallinity, chemical properties, and molecular structure. Coupons are commonly used to analyze the degradation of polymers. They are point sensors and did not give real-time information. Polymers are dielectric materials, and this dielectric property can be studied using Impedance Analyzer and Dielectric Spectroscopy. This review presents a brief status report on the failure of polymer liners in pipelines due to the exposure of acid gases, hydrocarbons, and other contaminants. Permeation, liner failures, the importance of monitoring, and new exclusive (dielectric) property are briefly discussed. An inclusive perspective is provided, showing the challenges associated with the monitoring of the polymer liner material in the pipeline as it relates to the life-time prediction requirement.
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Yang Y, Narayanan Nair AK, Sun S. Sorption and Diffusion of Methane and Carbon Dioxide in Amorphous Poly(alkyl acrylates): A Molecular Simulation Study. J Phys Chem B 2020; 124:1301-1310. [PMID: 31995385 DOI: 10.1021/acs.jpcb.9b11840] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Molecular simulations were carried out to understand the structural features and the sorption and diffusion behavior of methane and carbon dioxide in amorphous poly(alkyl acrylates) in the temperature range of 300-600 K. The hybrid Monte Carlo/molecular dynamics approach was employed to address the effects of polymer swelling and framework flexibility on the gas sorption. Simulations show that the glass-transition temperature decreases with the side-chain length of poly(alkyl acrylate), consistent with experiments. This is due to the fact that the shielding of the polar ester groups increases with the side-chain length. The simulated sorption isotherms for methane and carbon dioxide were in agreement with the experimental data. The polymer swelling becomes more pronounced, especially in the case of sorption of carbon dioxide. A significant swelling occurs, possibly because of the greater interaction between carbon dioxide and the polar ester groups in the polymers. The uptake of methane and carbon dioxide by poly(alkyl acrylates) generally increases with the side-chain length. Our simulations confirm the experimental findings that the diffusion coefficients of methane and carbon dioxide in poly(alkyl acrylates) increase with the side-chain length. Interestingly, the activation energies of gas diffusion decrease with the side-chain length. The diffusion coefficients of the penetrants have an exponential relationship with the void fraction, which is in agreement with the free volume theory.
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Affiliation(s)
- Yafan Yang
- Physical Science and Engineering Division (PSE), Computational Transport Phenomena Laboratory , King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900 , Saudi Arabia
| | - Arun Kumar Narayanan Nair
- Physical Science and Engineering Division (PSE), Computational Transport Phenomena Laboratory , King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900 , Saudi Arabia
| | - Shuyu Sun
- Physical Science and Engineering Division (PSE), Computational Transport Phenomena Laboratory , King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900 , Saudi Arabia
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Wenzel JE, Moorman V, Wang L, Spencer‐Williams I, Hall M, Samaniego CS, Ammerman ML. In-situ extraction and impregnation of black walnut husk into polyethylene film using supercritical carbon dioxide with an ethanol modifier. Food Sci Nutr 2020; 8:612-619. [PMID: 31993184 PMCID: PMC6977517 DOI: 10.1002/fsn3.1348] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 11/14/2019] [Indexed: 01/02/2023] Open
Abstract
Walnuts are commonly cultivated for their kernel, which is a rich source of antioxidant phenolic compounds. The husk likewise contains antioxidant and antimicrobial compounds, but is typically discarded without further processing. Antioxidant compounds are useful in creating active packaging films, but typically decompose at melt extrusion temperatures in polymer processing. Due to carbon dioxide's low critical point and ability to swell polymer films, supercritical carbon dioxide may be used to impregnate phenolic compounds into polymers. For this study, a novel technique is used to simultaneously produce walnut husk extracts and impregnate the extract into polymer films in the same batch extractor using supercritical carbon dioxide with a 15 wt-% ethanol modifier at 60°C at 19.4 MPa. The effect of varying the loading of walnut husk in the extractor upon impregnation mass was evaluated with the impregnation mass of the film increasing with walnut husk loading. It was determined by FTIR, as well as the reduction of the protein cytochrome c, that antioxidant compounds may be extracted from walnut husks and impregnated into low-density polyethylene film (LDPE) by this technique.
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Jahan N, Mighri F, Rodrigue D, Ajji A. Thermally stable cellular poly(vinylidene) ferroelectrets: Optimization of CO
2
driven inflation process. J Appl Polym Sci 2019. [DOI: 10.1002/app.47929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Nusrat Jahan
- CREPEC: Research Center for High Performance Polymer and Composite Systems, 2500 Chemin Polytechnique Montréal Quebec H3T 1J4 Canada
- Department of Chemical Engineering, Polytechnique Montréal C.P. 6079, Montreal Quebec H3C 3A7 Canada
| | - Frej Mighri
- CREPEC: Research Center for High Performance Polymer and Composite Systems, 2500 Chemin Polytechnique Montréal Quebec H3T 1J4 Canada
- Department of Chemical EngineeringUniversité Laval QC Quebec G1V 0A6 Canada
| | - Denis Rodrigue
- CREPEC: Research Center for High Performance Polymer and Composite Systems, 2500 Chemin Polytechnique Montréal Quebec H3T 1J4 Canada
- Department of Chemical EngineeringUniversité Laval QC Quebec G1V 0A6 Canada
| | - Abdellah Ajji
- CREPEC: Research Center for High Performance Polymer and Composite Systems, 2500 Chemin Polytechnique Montréal Quebec H3T 1J4 Canada
- Department of Chemical Engineering, Polytechnique Montréal C.P. 6079, Montreal Quebec H3C 3A7 Canada
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Yang Y, Narayanan Nair AK, Sun S. Adsorption and Diffusion of Methane and Carbon Dioxide in Amorphous Regions of Cross-Linked Polyethylene: A Molecular Simulation Study. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b00690] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Yafan Yang
- Computational Transport Phenomena Laboratory, Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Arun Kumar Narayanan Nair
- Computational Transport Phenomena Laboratory, Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Shuyu Sun
- Computational Transport Phenomena Laboratory, Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
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Jahan N, Mighri F, Rodrigue D, Ajji A. Effect of the inflation strategy on the piezoelectric response of cellular poly(vinylidene fluoride) ferroelectret. J Appl Polym Sci 2019. [DOI: 10.1002/app.47540] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Nusrat Jahan
- CREPEC, Research Center for High Performance Polymer and Composite Systems, 2500 Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
- Department of Chemical Engineering; Polytechnique Montréal; C.P. 6079, Montreal QC H3C 3A7 Canada
| | - Frej Mighri
- CREPEC, Research Center for High Performance Polymer and Composite Systems, 2500 Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
- Department of Chemical Engineering; Université Laval; Quebec QC G1V 0A6 Canada
| | - Denis Rodrigue
- CREPEC, Research Center for High Performance Polymer and Composite Systems, 2500 Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
- Department of Chemical Engineering; Université Laval; Quebec QC G1V 0A6 Canada
| | - Abdellah Ajji
- CREPEC, Research Center for High Performance Polymer and Composite Systems, 2500 Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
- Department of Chemical Engineering; Polytechnique Montréal; C.P. 6079, Montreal QC H3C 3A7 Canada
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Sterr J, Fleckenstein BS, Langowski HC. The Theory of Decompression Failure in Polymers During the High-Pressure Processing of Food. FOOD ENGINEERING REVIEWS 2017. [DOI: 10.1007/s12393-017-9171-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Taguchi T, Saito H. Effects of plasticization and hydrostatic pressure on tensile properties of PMMA under compressed carbon dioxide and nitrogen. J Appl Polym Sci 2016. [DOI: 10.1002/app.43431] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Tomoaki Taguchi
- Department of Organic and Polymer Materials Chemistry; Tokyo University of Agriculture and Technology; Koganei-Shi, Tokyo 184-8588 Japan
| | - Hiromu Saito
- Department of Organic and Polymer Materials Chemistry; Tokyo University of Agriculture and Technology; Koganei-Shi, Tokyo 184-8588 Japan
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11
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Sterr J, Rötzer K, Weck K, Wirth ALK, Fleckenstein BS, Langowski HC. In-situ measurement of oxygen concentration under high pressure and the application to oxygen permeation through polymer films. J Chem Phys 2015; 143:114201. [PMID: 26395698 DOI: 10.1063/1.4931399] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Up until now, gas permeation through polymers under high pressure has not been able to be measured continuously. The combination of a special high pressure cell and a commercially available fluorescence-based oxygen measurement system allows in-situ monitoring of oxygen permeation through a polymer sample under pressure in an aqueous environment. The principle of the oxygen sensor is based on dynamic fluorescence quenching and measurement of the fluorescence decay time. It was observed that the decay time increases non-linearly with the applied pressure, and hence, the displayed oxygen concentration has to be corrected. This deviation between the measured and the real concentration depends not only on the pressure but also on the absolute oxygen concentration in the water. To obtain a calibration curve, tests were performed in the pressure range between 1 and 2000 bars and initial oxygen concentrations in the range between 40 and 280 μmol/l. The polynomial calibration curve was of the fourth order, describing the raw data with a coefficient of determination R(2) > 0.99. The effective oxygen permeation through polymeric samples can be calculated with this function. A pressure hysteresis test was undertaken but no hysteresis was found. No temperature dependence of the oxygen sensor signal was observed in the range between 20 °C and 30 °C. This study presents for the first time data showing the oxygen permeation rates through a polyethylene film in the pressure range between 1 and 2000 bars at 23 °C.
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Affiliation(s)
- Julia Sterr
- Center of Life and Food Sciences Weihenstephan, Technische Universität München, Freising-Weihenstephan, Germany
| | - Katharina Rötzer
- Center of Life and Food Sciences Weihenstephan, Technische Universität München, Freising-Weihenstephan, Germany
| | - Kathrin Weck
- Center of Life and Food Sciences Weihenstephan, Technische Universität München, Freising-Weihenstephan, Germany
| | - Andreas Leonhard Karl Wirth
- Center of Life and Food Sciences Weihenstephan, Technische Universität München, Freising-Weihenstephan, Germany
| | | | - Horst-Christian Langowski
- Center of Life and Food Sciences Weihenstephan, Technische Universität München, Freising-Weihenstephan, Germany
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Influence of high pressures on CH4, CO2 and H2S solubility in polyethylene: Experimental and molecular simulation approaches for pure gas and gas mixtures. Modelling of the sorption isotherms. J Memb Sci 2015. [DOI: 10.1016/j.memsci.2015.04.040] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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13
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From Solutions to Polymers: A High Temperature–High Pressure Journey in Experimental Thermodynamics. J SOLUTION CHEM 2015. [DOI: 10.1007/s10953-015-0302-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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14
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Sterr J, Fleckenstein BS, Langowski HC. The Effect of High-Pressure Processing on Tray Packages with Modified Atmosphere. FOOD ENGINEERING REVIEWS 2014. [DOI: 10.1007/s12393-014-9081-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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15
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Boyer SA, Gerland M, Castagnet S. Gas environment effect on cavitation damage in stretched polyvinylidene fluoride. POLYM ENG SCI 2013. [DOI: 10.1002/pen.23759] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Séverine A.E. Boyer
- INSTITUT PPRIME-P' - ISAE-ENSMA; UPR 3346 - Laboratoire de Mécanique et Physique des Matériaux, Téléport 2, Avenue Clément Ader, 86961 Futuroscope Chasseneuil France
| | - Michel Gerland
- INSTITUT PPRIME-P' - ISAE-ENSMA; UPR 3346 - Laboratoire de Mécanique et Physique des Matériaux, Téléport 2, Avenue Clément Ader, 86961 Futuroscope Chasseneuil France
| | - Sylvie Castagnet
- INSTITUT PPRIME-P' - ISAE-ENSMA; UPR 3346 - Laboratoire de Mécanique et Physique des Matériaux, Téléport 2, Avenue Clément Ader, 86961 Futuroscope Chasseneuil France
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16
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Akin O, Temelli F. Performance characterization of polyamide reverse osmosis membranes upon supercritical CO2 processing. J Supercrit Fluids 2012. [DOI: 10.1016/j.supflu.2011.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lin S, Yang J, Yan J, Zhao Y, Yang B. Sorption and Diffusion of Supercritical Carbon Dioxide in a Biodegradable Polymer. J MACROMOL SCI B 2010. [DOI: 10.1080/01495930903352308] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Shiquan Lin
- a School of Chemistry and Chemical Engineering , Shanghai Jiao Tong University , Shanghai, China
| | - Jing Yang
- a School of Chemistry and Chemical Engineering , Shanghai Jiao Tong University , Shanghai, China
| | - Jiefeng Yan
- a School of Chemistry and Chemical Engineering , Shanghai Jiao Tong University , Shanghai, China
| | - Yaping Zhao
- a School of Chemistry and Chemical Engineering , Shanghai Jiao Tong University , Shanghai, China
| | - Bin Yang
- a School of Chemistry and Chemical Engineering , Shanghai Jiao Tong University , Shanghai, China
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18
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Grolier JPE, Boyer SAE. Gas–Polymer Interactions: Key Thermodynamic Data and Thermophysical Properties. POLYMER THERMODYNAMICS 2010. [DOI: 10.1007/12_2010_83] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Boyer SAE, Yamada T, Yoshida H, Grolier JPE. Modification of molecular organization of polymers by gas sorption: Thermodynamic aspects and industrial applications. PURE APPL CHEM 2009. [DOI: 10.1351/pac-con-08-11-09] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In polymer science, gas–polymer interactions play a central role for the development of new polymeric structures for specific applications. This is typically the case for polymer foaming and for self-assembling of nanoscale structures where the nature of the gas and the thermodynamic conditions are essential to control. An important applied field where gas sorption in polymers has to be documented through intensive investigations concerns the (non)-controlled solubilization of light gases in the polymers serving, for example, in the oil industry for the transport of petroleum fluids. An experimental set-up coupling a vibrating-wire (VW) detector and a pVT technique has been used to simultaneously evaluate the amount of gas entering a polymer under controlled temperature and pressure and the concomitant swelling of the polymer. Scanning transitiometry has been used to determine the interaction energy during gas sorption in different polymers; the technique was also used to determine the thermophysical properties of polymers submitted to gas sorption. The role of the pressurizing fluid has been documented in terms of the influence of pressure, temperature, and nature of the fluid.
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Affiliation(s)
- Séverine A. E. Boyer
- 1Centre for Material Forming, CEMEF (CNRS UMR 7635), Mines ParisTech, 06904 Sophia Antipolis, France
| | - Takeshi Yamada
- 2Institute for Solid State Physics, The University of Tokyo, Tokyo, Kashiwa 277-8581, Japan
| | - Hirohisa Yoshida
- 3Graduate School of Environmental Science, Tokyo Metropolitan University, Hachiouji Tokyo 198-0397, Japan
| | - Jean-Pierre E. Grolier
- 4Laboratory of Thermodynamics of Solutions and Polymers, Blaise Pascal University, 63177 Aubière, France
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Boyer SA, Grolier JPE, Yoshida H, Haudin JM, Chenot JL. Phase transitions of polymers over T and P ranges under various hydraulic fluids: Polymer/supercritical gas systems and liquid to solid polymer transitions. J Mol Liq 2009. [DOI: 10.1016/j.molliq.2009.01.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Charpentier PA, Li X, Sui R. Study of the sol-gel reaction mechanism in supercritical CO2 for the formation of SiO2 nanocomposites. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:3748-3754. [PMID: 19231832 DOI: 10.1021/la803449z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Direct sol-gel reactions in supercritical CO2 (scCO2) have attracted significant interest for synthesizing nanomaterials by reacting alkoxides with a carboxylic acid. In this study, the hydrolysis of silicon alkoxides (TEOS or TMOS) was carried out using scCO2 as the solvent to generate silica nanoparticles within the matrix of polyethylene for the synthesis of polymeric nanocomposites. This methodology provides advantages of combining the sol-gel reactions and drying into a one-step process for producing polymer nanocomposites. The synthesized polymer silica composites were characterized by SEM, FTIR, and XPS. When the TEOS loading was below 10 wt % Si content, nanometer-sized silica particles were formed that were well dispersed within the polyethylene matrix. The mechanism of the silicon alkoxides reacting with acetic acid in scCO2 was further studied using online GC-MS and offline 13C NMR. Oligomer structures with a bridging methoxyl group between the two silicon atoms and the acetate monodentate were observed. This study suggests a new sol-gel pathway in scCO2 that is different from the hydrolysis-condensation reactions using the conventional sol-gel process.
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Affiliation(s)
- Paul A Charpentier
- Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario, Canada N6A 5B9.
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