Carbon Dioxide Permeability Research Articles

Ultraviolet protection of recycled polyethylene terephthalate

ABSTRACTPolyethylene terephthalate (PET) is commonly used for food packaging due to its high clarity, high resistance to water vapor, oxygen and carbon dioxide permeation, and good mechanical properties. However, its high transmittance in the ultraviolet‐A (UVA) region leaves food susceptible to UV‐induced degradation reactions. Incorporating post‐consumer recycled (PCR) PET into virgin PET increased UVA absorption 100% when utilizing 100% PCR‐PET, thus, increasing the protection potential of food packaging by reducing UVA‐induced degradation reactions. Comparison of the current data with previous work demonstrated the reproducibility of UVA protection independent of the PC flake source. The thickness‐normalized absorbance at 350 nm was a reliable predictor of the UVA protection potential regardless of composition and manufacture date. Raman, fluorescence, and attenuated total reflectance‐Fourier transform infrared spectroscopy analyses provided support that the UVA absorbing moiety was a quinone derivative formed during degradation reactions that are known to occur during melt processing/re‐processing. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45181.

Description of the gas transport through dynamic liquid membrane

Description of the gas transport through dynamic liquid membrane

Cellulose Nanocrystals from Lignocellulosic Raw Materials, for Oxygen Barrier Coatings on Food Packaging Films

Cellulose nanocrystals (CNCs) are unique, renewable top-down nano particles from which coatings with improved gas barrier properties and new functionalities can be prepared. In this paper, the potential for obtaining such high performing nanocrystals from low-cost lignocellulosic by-products or raw materials is proved by a comparison study on CNCs obtained both from cotton linters and kraft pulp, by means of the ammonium persulfate (APS) process. Morphological and chemical characterization of the nanocrystals obtained, as well as the main functional properties of the poly(ethylene terephthalate) coated films, showed quite similar characteristics and performances of CNCs obtained from pure cellulose raw material (cotton linters) and the nanoparticles produced from a potential discard of paper making processes (kraft pulp). In particular, the gas barrier properties of the coating produced with CNCs obtained from kraft pulp were very promising, providing oxygen and carbon dioxide permeability values hundreds of times lower than those of equal thickness in comparison with common barrier synthetic polymers, over a broad range of temperatures. The results obtained are relevant not only for the outstanding performances achieved, but also because they evoke a possible positive example of industrial symbiosis in the packaging field, merging together the requirements and needs of the paper and plastic industries and addressing the way towards a better management of waste and materials. Copyright © 2017 John Wiley & Sons, Ltd.

Can the addition of carbon nanoparticles to a polyimide membrane reduce plasticization?

Can the addition of carbon nanoparticles to a polyimide membrane reduce plasticization?

Improved mechanical properties, barrier properties and degradation behavior of poly(butylenes adipate-co-terephthalate)/poly(propylene carbonate) films

Poly(butylene adipate-co-terephthalate) (PBAT) was blended with poly(propylene carbonate) (PPC) by a twin screw extruder and then the blends were made onto films via the blown film technique. PPC dispersed uniformly in the PBAT matrix, and the glass transition temperature (T g ) of PBAT were decreased with the increasing content of PPC. Wide angle X-ray diffraction confirmed that the crystallite dimension of PBAT was decreased after blending PBAT with the amorphous PPC. The results of mechanical tests indicated that the PBAT/PPC films showed high tensile strength and tear strength. In addition, the PBAT/PPC films showed high carbon dioxide permeability and moderate oxygen and nitrogen permeability. After embedding in soil, the weight loss and mechanical properties analysis demonstrated that the films were remarkably biodegraded. These findings contributed to application of the biodegradable materials, such as design and manufacture polymer packaging.

Aminosilane-functionalized ZIF-8/PEBA mixed matrix membrane for gas separation application

Aminosilane-functionalized ZIF-8/PEBA mixed matrix membrane for gas separation application

PBAT/organoclay composite films: preparation and properties

Environmental problems caused by the increased waste associated with short-term use of plastic materials, particularly by the food packaging industry, prompted the search for biodegradable alternatives. This contribution studied one of these alternatives, poly(butylene adipate-co-terephthalate)—PBAT, a polymer that is fully biodegradable in common landfills, compounded with a small amount of Cloisite 20A organoclay. Materials were mixed in a laboratory internal mixer and films prepared in a chill roll extruder. Results show that the presence of organoclay does not increase degradation of the polymer matrix during processing, nor affects its crystallization characteristics. However, organoclay addition significantly diminished oxygen and carbon dioxide permeability of the films, making them a very interesting alternative for the food packaging industry.

Investigation of gas pressure and temperature effects on the permeability and steady-state time of chinese anthracite coal: An experimental study

Investigation of gas pressure and temperature effects on the permeability and steady-state time of chinese anthracite coal: An experimental study

Effect of polyelectrolyte on the barrier efficacy of layer-by-layer nanoclay coatings

Effect of polyelectrolyte on the barrier efficacy of layer-by-layer nanoclay coatings

Gas Permeability and Permselectivity of Poly(L-Lactic Acid)/SiOx Film and Its Application in Equilibrium-Modified Atmosphere Packaging for Chilled Meat.

A layer of SiOx was deposited on the surface of poly(L-lactic acid) (PLLA) film to fabricate a PLLA/SiOx layered film, by plasma-enhanced chemical vapor deposition (PECVD) process. PLLA/SiOx film showed Young's modulus and tensile strength increased by 119.2% and 91.6%, respectively, over those of neat PLLA film. At 5 °C, the oxygen (O2 ) and carbon dioxide (CO2 ) permeability of PLLA/SiOx film decreased by 78.7% and 71.7%, respectively, and the CO2 /O2 permselectivity increased by 32.5%, compared to that of the neat PLLA film. When the PLLA/SiOx film was applied to the equilibrium-modified atmosphere packaging of chilled meat, the gas composition in packaging reached a dynamic equilibrium with 6% to 11% CO2 and 8% to 13% O2 . Combined with tea polyphenol pads, which effectively inhibited the microbial growth, the desirable color of meat was maintained and an extended shelf life of 52 d was achieved for the chilled meat.

Porous hollow fiber membranes with varying hydrophobic–hydrophilic surface properties for gas–liquid membrane contactors

In relation to the demand for asymmetric porous hollow fiber membranes to be used in gas–liquid membrane contactors designed for operation in organic media, polysulfone membranes of this type have been prepared and subsequently modified to impart oleophobic properties to their surface. The structure and properties of the membranes have been characterized using various techniques, such as optical and scanning electron microscopy, and by measuring contact angles and the permeability of helium, carbon dioxide, and hexane. The surface properties of the membranes have been modified by etching with a mixture of hydrogen peroxide and sulfuric acid or coating with a perfluorinated acrylic copolymer. In the latter case, modified membrane samples have shown a significant reduction in wettability with both water and organic liquids. The hexane permeability data indicate the absence of hexane flow through the membrane modified with perfluorinated acrylic copolymer until a gauge pressure of about 1 atm. The results of the study lead to the conclusion that these membranes can find use in gas–liquid membrane contactors, e.g., for the removal of dissolved gases from liquid hydrocarbons.

Simplified Approach Based on Polynomial Equations to Predict the Permeability of Micro‐perforated Polymeric Films

A simplified approach to predict the mass transport properties of micro‐perforated films was presented in this work. In particular, the proposed mathematical model was based on a second‐degree polynomial function. Different types of micro‐perforated films with two thicknesses (35 and 25 µm) were tested for gas and water vapour permeability, under proper conditions. The films differed in both number of holes per unit area and hole diameter. Corresponding non‐perforated films were also tested. The experimental data obtained were used to validate the model. Moreover, the surface response plot of the interactions between hole diameter and number of holes per area relative to oxygen, water vapour and carbon dioxide permeability were determined. Results of the mean relative deviation modulus (E%) between the experimental and predicted data confirmed the ability of the proposed model to predict the permeability of micro‐perforated films. Copyright © 2016 John Wiley & Sons, Ltd.

Aluminophosphate-17 and silicoaluminophosphate-17 membranes for CO2 separations

Aluminophosphate-17 and silicoaluminophosphate-17 membranes for CO2 separations

Permeability of carbon dioxide and nitrogen gases through SiO2 and MgO incorporated ENR/PVC membranes

Two mixed-matrix membranes (MMM) for gas permeability test were prepared by introducing inorganic fillers (silica (SiO2) and magnesium oxide (MgO)) in the composite blend of epoxidized natural rubber (ENR) and polyvinyl chloride (PVC). Inclusion of SiO2 and MgO particles in the membranes resulted in pores formation as observed through scanning electron microscopy. Thermal study demonstrated that there were interaction between the fillers and polymer matrix with SiO2 exhibited better interaction. SiO2 was also observed to disperse more evenly in the membrane compared to MgO. The permeability of carbon dioxide (CO2) and nitrogen (N2) gases was measured in order to determine the effects of SiO2 and MgO in CO2/N2 separation performance of the ENR/PVC/filler membranes. CO2 was found to exhibit higher permeability compared to N2 for all the membranes. The gas permeability of ENR/PVC/SiO2 membrane was significantly higher than ENR/PVC/MgO and ENR/PVC membranes. Interestingly, despite having lower permeability, MgO-filled membrane exhibited higher CO2/N2 selectivity. When compared to the Robeson’s upper bound, it was found that introduction of fillers had improved gas separation performance of ENR/PVC membrane.

The effect of temperature on the permeation properties of Sulphonated Poly (Ether Ether) Ketone in wet flue gas streams

The effect of temperature on the permeation properties of Sulphonated Poly (Ether Ether) Ketone in wet flue gas streams

Composite blending of ionic liquid–poly(ether sulfone) polymeric membranes: Green materials with potential for carbon dioxide/methane separation

ABSTRACTThe incorporation of imidazolium‐based ionic liquids into a poly(ether sulfone) (PES) polymeric membrane resulted in a dense and void‐free polymeric membrane. As determined through the ideal gas permeation test, the carbon dioxide (CO2) permeation increased about 22% compared to that of the pure PES polymeric membrane whereas the methane (CH4) permeation decreased tremendously. This made the CO2/CH4 ideal separation increase substantially by more than 100%. This study highlighted the utilization of imidazolium‐based ionic liquids in the synthesis of ionic liquid polymeric membranes (ILPMs). Two different ionic liquids were used to compare the CO2 separation performance through the membranes. The glass‐transition temperatures (Tgs) of ILPMs were found to be lower than the Tg of the pure PES polymeric membranes; this supported the high CO2 permeation of the ILPMs due to the increase in PES flexibility caused by ionic liquid addition. The results also draw attention to new trends of ionic liquids as a potential green candidates for future membrane synthesis. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43999.

Penetrant transport in semicrystalline poly(ethylene furanoate)

Penetrant transport in semicrystalline poly(ethylene furanoate)

Enzymatically-boosted ionic liquid gas separation membranes using carbonic anhydrase of biomass origin

Enzymatically-boosted ionic liquid gas separation membranes using carbonic anhydrase of biomass origin

Structural, thermal, and gas transport properties of HDPE/LLDPE blend‐based nanocomposites using a mixture of HDPE‐g‐MA and LLDPE‐g‐MA as compatibilizer

Nanocomposites based on high density polyethylene (HDPE)/linear low density polyethylene (LLDPE) blend were prepared by melt compounding in a twin‐screw extruder using organoclay (montmorillonite) as nano‐filler and a 50/50 wt% mixture of maleic anhydride functionalized high density polyethylene (HDPE‐g‐MA) and linear low density polyethylene (LLDPE‐g‐MA) as the compatibilizing system. The addition of a maleated polyethylene‐based compatibilizing system was required to improve the organoclay dispersion in the HDPE/LLDPE blend‐based nanocomposite. In this work, the relationships between thermal properties, gas transport properties, and morphology were correlated. The compatibilized nanocomposite exhibited an intercalated morphology with a small number of individual platelets dispersed in the HDPE/LLDPE matrix, leading to an significant decrease in the oxygen permeation coefficient of the nanocomposites. A decrease in the carbon dioxide permeability and oxygen permeability with increase of nanoclay was observed for the compatibilized nanocomposites. The carbon dioxide permeability of the compatibilized nanocomposites was lower than the carbon dioxide permeability of the uncompatibilized nanocomposites even with the low intrinsic barrier properties of the compatibilizer. These effects were attributed to a good dispersion of the inorganic filler, good wettability of the filler by the polymer matrix, and strong interactions at the interface that increased the tortuous path for diffusion. Theoretical permeability models were used to estimate the final aspect ratio of nanoclay in the nanocomposite and showed good agreement with the aspect ratio obtained directly from TEM images. POLYM. ENG. SCI., 56:765–775, 2016. © 2016 Society of Plastics Engineers

Prediction of gas transport across amine mixed matrix membranes with ideal morphologies based on the Maxwell model

The incorporation of highly selective molecular sieve such as carbon molecular sieve (CMS) and highly affinitive solvent such as diethanolamine (DEA) into polyethersulfone (PES) have been implemented to synthesize amine mixed matrix membranes (MMMs) with an enhanced gas performance. Synergetic effect of CMS and DEA has caused the improvement of carbon dioxide (CO2) permeability and ideal CO2/CH4 selectivity. While existing theoretical models define the relative permeability well for binary mixed matrix membranes they fail to predict the relative permeability of amine mixed matrix membranes. In fact, the degree of deviation from the simple model predictions provides understanding into the detailed properties of the third component, which has been neglected in previous analyses of these models. Modification of an existing model, namely the Maxwell model, provides an outline to analyze the gas permeation properties of model systems with CMS and DEA in glassy polymer phase. The new model is developed by modifying the basic Maxwell MMMs model. The modification also includes the optimization of λdm, which is defined as the ratio of dispersed phase permeability to matrix permeability, and the determination of permeability of the dispersed phase. Furthermore, this Maxwell model has been extended to model the performance of amine mixed matrix membranes by incorporation of combined volume fraction of filler and amine φ*ad. The proposed approach can predict the permeability of CO2 through amine MMMs and also lowers the AARE % value.