| 1. |
- Reddy, C. Nagendranatha, et al.
(author)
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Review of microplastic degradation : Understanding metagenomic approaches for microplastic degrading organisms
- 2023
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In: Polymer testing. - : Elsevier BV. - 0142-9418 .- 1873-2348. ; 128, s. 108223-
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Research review (peer-reviewed)abstract
- Environmental problems caused by plastic pollution are among the most pressing issues of our time. In recent years, metagenomics has become a powerful tool for understanding the microbial communities responsible for plastic biodegradation. In this review, recent developments and trends in metagenomics are discussed, and a comprehensive overview of the metagenomic methodology, analysis, and comparison of plastic-degrading bacteria is provided. In addition, the environmental consequences of plastic degradation are discussed, such as the impact on soil, water, and air quality, as well as the potential health risks posed by ingesting and inhaling microplastics. Possible solutions to the plastic degradation problem, such as using biodegradable materials and implementing recycling programs, are also explained. This review highlights the potential impact of metagenomics on the development of sustainable solutions to plastic pollution.
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| 2. |
- Sanandaji, Nima, et al.
(author)
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Unusual crystals of poly(epsilon-caprolactone) by unusual crystallisation : The effects of rapid cooling and fast solvent loss on the morphology, crystal structure and melting
- 2013
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In: Polymer. - : Elsevier BV. - 0032-3861 .- 1873-2291. ; 54:5, s. 1497-1503
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Journal article (peer-reviewed)abstract
- The lateral habit, unit cell structure and melting behaviour of single crystals of poly(epsilon-caprolactone) (PCL) prepared by the rapid expansion of a supercritical solution technique was studied by AFM at ambient and higher temperatures and by grazing-incident X-ray scattering using a synchrotron source. After dissolving PCL in a solution of supercritical CO2 and 0.1 vol.% chloroform, an extremely fast phase transfer from a supercritical to a gas-like state occurred during expansion into atmospheric conditions, leading to a temporary temperature drop to below -;50 degrees C at the silica surface where the crystals were deposited. Single crystals of a hitherto unreported rectangular lateral habit were observed. Six-sided crystals were also observed, but they were fewer than the rectangular crystals and in addition the angles between the lateral faces were different from the theoretical angles between adjacent {110} faces and {110} and {100} faces. X-ray scattering indicated a polymorphic structure also including the orthorhombic (110) and (200) diffraction peaks. Distinct low angle peaks essentially along the c-axis indicated a stacking on a very fine scale (3.7-4.7 nm) within the crystals. The equatorial diffraction peaks indicated a less dense packing of the PCL stems. Rectangular single crystals with a height according to AFM of 11-27 nm melted between 40 and 45 degrees C, which is lower than the melting points (55 degrees C) recorded for the distorted six-sided crystals. The unusual conditions for crystallisation used gave the polymer molecules a severe limitation to rearrange from the initial random coil state. The facetted crystals consisted of a stack of 4 nm thick blocks; these blocks most probably constituted a regular variation in molecular packing, i.e. molecular order. The pronounced changes in the angles between adjacent faces from those observed in mature PCL crystals and the wide-angle X-ray scattering data indicated the presence of conformational disorder in the crystals.
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| 3. |
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| 4. |
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| 5. |
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| 6. |
- Johansson, Kenth S., et al.
(author)
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Surface modification of wheat gluten films for improved water resistance
- 2010
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In: Abstracts of Papers of the American Chemical Society. - : American Chemical Society (ACS). - 0065-7727. ; 240
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Journal article (other academic/artistic)abstract
- Renewable packaging materials are of interest for a more sustainable environment, and wheat gluten (WG) is one of the most interesting candidates to replace petroleum-based oxygen-barrier polymers for packaging applications. This is due to its attractive combination of flexibility and strength, high gas (especially O2) barrier properties under low humidity conditions and renewability. The main drawback of WG, as with most biopolymers, is its water and moisture sensitivity. The aim of this study was therefore to improve the hydrophobicity of WG films by means of surface modification while maintaining the excellent O2 barrier properties. The surface modification work included a combination of electrospinning of WG fibers and different plasma surface modifications. The latter involved He plasma treatment for crosslinking the WG film prior to the deposition of electrospun WG fibers, O2/Ar plasma etching of the WG films with and without electrospun WG fibers for increasing the surface roughness, and plasma polymerization of hexamethyldisiloxane (HMDSO) and other hydrophobic precursors for hydrophobicity. The plasma polymerization trials were performed both at reduced and atmospheric pressure conditions. The aim of the combined work was to maximize the hydrophobicity by combining a suitable nano-microstructure of the WG fibers with the hydrophobicity of the plasma-deposited coatings. The surface modification work was mainly evaluated by means of water contact angle measurements (hydrophobicity), Scanning Electron Microscopy (surface structures), Water Vapor Transmission Rate (WVTR) (moisture barrier) and Oxygen Transmission Rate (OTR) measurements (oxygen barrier). The surface modification work resulted in significantly improved hydrophobic properties of the WG films. The initial water contact angle increased from 65 to 110-130 degrees, depending on the combinations of electrospinning and plasma modification conditions. The plasma coatings prepared at ambient conditions resulted in slightly lower contact angles compared the plasma coating prepared at reduced pressure. The WVTR and OTR measurements are still in progress and will be reported at the meeting.
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| 7. |
- Kuktaite, Ramune, et al.
(author)
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Monitoring Nanostructure Dynamics and Polymerization in Glycerol Plasticized Wheat Gliadin and Glutenin Films : Relation to Mechanical Properties
- 2016
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In: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 4:6, s. 2998-3007
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Journal article (peer-reviewed)abstract
- Gliadin and glutenin proteins with 10, 20, 30 and 40% of glycerol were compression molded into films (130 °C) and evaluated for protein polymerization, β-sheet structure and nano-structural morphology. Here, for the first time we show how different amounts of glycerol impact the nano-structure and functional properties of the gliadin and glutenin films. Most polymerized protein was found in the gliadin films with 20 and 30% glycerol, and in all the glutenin films (except 10%), by RP-HPLC. A β-sheet-rich protein structure was found to be high in the 10 and 20% glycerol gliadin films, and in the 20 and 30% glycerol glutenin films by FT-IR. Glycerol content of 20, 30 and 40% impacted the nano-structural morphology of the gliadin glycerol films observed by SAXS, and to a limited extent for 10 and 20% glycerol gliadin films revealed by WAXS. No ordered nano-structure was found for the glutenin glycerol films. The 20%, 30% and 40% glycerol films were the most tunable for specific mechanical properties. For the highest stiffness and strength, the 10% glycerol protein films were the best choice.
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| 8. |
- Muneer, Faraz, et al.
(author)
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Innovative Gliadin/Glutenin and Modified Potato Starch Green Composites : Chemistry, Structure, and Functionality Induced by Processing
- 2016
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In: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 4:12, s. 6332-6343
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Journal article (peer-reviewed)abstract
- In this study, we combined two wheat proteins, gliadin (Gli)/glutenin (GT), and modified potato starch (MPS) into composites using extrusion. In the Gli/GT MPS composites, we studied the structural dynamics of proteins and starch, protein starch interactions, protein properties, and composite morphology in relation to mechanical and barrier properties. Materials with different ratios of Gli/GT and MPS were extruded using either glycerol or glycerol water at 110 and 130 degrees C. For the first time, a hierarchical hexagonal structure of Gli proteins was observed in Gli MPS composite at both extrusion temperatures. The higher temperature (130 degrees C) induced a higher degree of protein cross-links, an increase in the polymer size, and formation of beta-sheets compared to 110 degrees C. The combination of plasticizers (glycerol and water) favored a micro-structural morphology with improved gelatinization of starch, processability, as well as strength, stiffness, and extensibility of GT MPS composites. The highest amount of the oxidized proteins was observed in the samples with the highest protein content and at high extrusion temperature. The Gli- and GT MPS (30/70) samples showed promising oxygen barrier properties under ambient testing conditions. These findings provide in-depth information for tailoring the structural functional relationship of the Gli/GT-potato starch composites for their promising use in designing various green materials.
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| 9. |
- Plackett, David, et al.
(author)
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Physical Properties and Morphology of Films Prepared from Microfibrillated Cellulose and Microfibrillated Cellulose in Combination with Amylopectin
- 2010
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In: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 117:6, s. 3601-3609
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Journal article (peer-reviewed)abstract
- Two types of microfibrillated cellulose (MFC) were prepared using either a sulfite pulp containing a high amount of hemicellulose (MFC 1) or a carboxymethylated dissolving pulp (MFC 2). MFC gels were then combined with amylopectin solutions to produce solvent-cast MFC-reinforced amylopectin films. Tensile testing revealed that MFC 2-reinforced films exhibited a more ductile behavior and that MFC 1-reinforced films had higher modulus of elasticity (E-modulus) at MFC loadings of 50 wt % or higher. Pure MFC films had relatively low oxygen permeability values when data were compared with those for a variety of other polymer films. MFC 1 and MFC 2 films had similar opacity but differences in appearance which were attributed to the presence of some larger fibers and nanofiber agglomerates in MFC 2. Field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) were used to illustrate the morphology of MFC nanofibers in pure films and in an amylopectin matrix.
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| 10. |
- Rasheed, Faiza, et al.
(author)
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Structural architecture and solubility of native and modified gliadin and glutenin proteins : non-crystalline molecular and atomic organization
- 2014
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In: RSC Advances. - 2046-2069. ; 4:4, s. 2051-2060
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Journal article (peer-reviewed)abstract
- Wheat gluten (WG) and its components, gliadin and glutenin proteins, form the largest polymers in nature, which complicates the structural architecture of these proteins. Wheat gluten, gliadin and glutenin proteins in unmodified form showed few secondary structural features. Structural modification of these proteins using heat, pressure and the chemical chaperone glycerol resulted in a shift to organized structure. In modified gliadin, nano-structural molecular arrangements in the form of hexagonal closed packed (HCP) assemblies with lattice parameter of (58 angstrom) were obvious together with development of intermolecular disulphide bonds. Modification of glutenin resulted in highly polymerized structure with proteins linked not only by disulphide bonds, but also with other covalent and irreversible bonds, as well as the highest proportion of beta-sheets. From a combination of experimental evidence and protein algorithms, we have proposed tertiary structure models of unmodified and modified gliadin and glutenin proteins. An increased understanding of gliadin and glutenin proteins structure and behavior are of utmost importance to understand the applicability of these proteins for various applications including plastic materials, foams, adhesives, films and coatings.
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| 11. |
- Rasheed, Faiza, et al.
(author)
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The use of plants as a "green factory" to produce high strength gluten-based materials
- 2016
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In: Green Chemistry. - : Royal Society of Chemistry. - 1463-9262 .- 1463-9270. ; 18:9, s. 2782-2792
-
Journal article (peer-reviewed)abstract
- The aim of the present study was to develop an understanding of how wheat plants can be used as a "green factory" by the modulation of genotype (G) and environmental (E) interactions to fine-tune the structure and increase the strength of gluten based materials. Two wheat genotypes (5 + 10 and 2 + 12) were grown under four nitrogen and two temperature regimes to obtain gluten of various characteristics. Protein microstructure morphology revealed by confocal laser scanning microscopy suggested a higher polymerisation of proteins in glycerol plasticized films from the 5 + 10 compared to the 2 + 12 genotype. Also, films with the highest Young's modulus and maximum stress were obtained from the 5 + 10 genotype, which might be explained by the higher number of cysteine residues and consequently more disulphide crosslinks in this genotype compared to the 2 + 12 one. The presence of two nano-scaled morphologies, hexagonal and lamellar structures and their internal relations were found to be of relevance for formation of beta-sheets and also to be related to performance (strength) of the material. Thus, plants could be used as a "green factory", avoiding the use of chemicals, to tune the tensile properties of the materials. Structural properties such as relatively low protein aggregation, high beta-sheet content and a high hexagonal to lamellar structural ratio at the nano-scale were found to yield films with high stiffness and strength.
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| 12. |
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| 13. |
- Bjurstrom, Anton, et al.
(author)
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A Review of Polyolefin-Insulation Materials in High Voltage Transmission; From Electronic Structures to Final Products
- 2024
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In: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095.
-
Research review (peer-reviewed)abstract
- This review focuses on the use of polyolefins in high-voltage direct-current (HVDC) cables and capacitors. A short description of the latest evolution and current use of HVDC cables and capacitors is first provided, followed by the basics of electric insulation and capacitor functions. Methods to determine dielectric properties are described, including charge transport, space charges, resistivity, dielectric loss, and breakdown strength. The semicrystalline structure of polyethylene and isotactic polypropylene is described, and the way it relates to the dielectric properties is discussed. A significant part of the review is devoted to describing the state of art of the modeling and prediction of electric or dielectric properties of polyolefins with consideration of both atomistic and continuum approaches. Furthermore, the effects of the purity of the materials and the presence of nanoparticles are presented, and the review ends with the sustainability aspects of these materials. In summary, the effective use of modeling in combination with experimental work is described as an important route toward understanding and designing the next generations of materials for electrical insulation in high-voltage transmission.
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| 14. |
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| 15. |
- Chen, Fei, et al.
(author)
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Wheat gluten/chitosan blends : A new biobased material
- 2014
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In: European Polymer Journal. - : Elsevier BV. - 0014-3057 .- 1873-1945. ; 60, s. 186-197
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Journal article (peer-reviewed)abstract
- Wheat gluten and chitosan are renewable materials that suffer from some poor properties that limit their use as a potential replacement of petroleum-based polymers. However, polymer blends based on wheat gluten and chitosan surprisingly reduced these shortcomings. Films were cast from acidic aqueous or water/ethanol solutions of wheat gluten and chitosan. Wheat gluten was the discontinuous phase in the 30-70 wt.% wheat gluten interval investigated. The most homogeneous films were obtained when reducing agents were used (alone or together with urea or glycerol). They consisted mainly of 1-2 mu m wheat gluten particles uniformly distributed in the continuous chitosan phase. Slightly smaller particles were also observed in the water/ethanol solvent system, but together with significantly larger particles (as large as 200 mu m). Both small and large particles were observed, albeit in different sizes and contents, when surfactants (both with and without a reducing agent) or urea (without a reducing agent) were used. The particles were often elongated, and preferably along the film, the most extreme case being observed when the glyoxal crosslinker was used together with sodium sulfite (reducing agent), showing particles with an average thickness of 0.6 mu m and an aspect ratio of 4.2. This film showed the highest transparency of all the blend films studied. For one of the most promising systems (with sodium sulfite), having good film homogeneity and small particles, the mechanical and moisture solubility/diffusivity properties were studied as a function of chitosan content. The extensibility, toughness and moisture solubility increased with increasing chitosan content, and the moisture diffusivity was highest for the pristine chitosan material. It is noteworthy that the addition of 30 wt.% wheat gluten to chitosan reduced the moisture uptake, while the extensibility/toughness remained unchanged.
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| 16. |
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| 17. |
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| 18. |
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| 19. |
- Cho, Sung-Woo, et al.
(author)
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Effects of glycerol content and film thickness on the properties of vital wheat gluten films cast at pH 4 and 1
- 2010
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In: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 117:6, s. 3506-3514
-
Journal article (peer-reviewed)abstract
- This study deals with the optical properties and plasticizer migration properties of vital wheat gluten (WG) films cast at pH 4 and 11. The films contained initially 8, 16, and 25 wt % glycerol and were aged at 23 degrees C and 50% relative humidity for at least 17 weeks on a paper support to simulate a situation where a paper packaging is laminated with an oxygen barrier film of WG. The films, having target thicknesses of 50 and 250 mu m, were characterized visually and with ultraviolet/visible and infrared spectroscopy; the mass loss was measured by gravimetry or by a glycerol-specific gas chromatography method. The thin films produced at pH 4 were, in general, more heterogeneous than those produced at pH 11. The thin pH 4 films consisted of transparent regions surrounding beige glycerol-rich regions, the former probably rich in gliadin and the latter rich in glutenin. This, together with less Maillard browning, meant that the thin pH 4 films, in contrast to the more homogeneous (beige) thin pH 11 films, showed good contact clarity. The variations in glycerol content did not significantly change the optical properties of the films. All the films showed a significant loss of glycerol to the paper support but, after almost 9 months, the thick pH 11 film containing initially 25 wt % glycerol was still very flexible and, despite a better contact to the paper, had a higher residual glycerol content than the pH 4 film, which was also more brittle.
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| 20. |
- Cho, Sung-Woo, et al.
(author)
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Effects of glycerol content and film thickness on the properties of vital wheat gluten films cast at pH 4 and 11
- 2010
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In: Journal of Applied Polymer Science. - : John Wiley & Sons, Inc.. - 0021-8995 .- 1097-4628. ; 117:6, s. 3506-3514
-
Journal article (peer-reviewed)abstract
- This study deals with the optical properties and plasticizer migration properties of vital wheat gluten (WG) films cast at pH 4 and 11. The films contained initially 8, 16, and 25 wt.% glycerol and were aged at 23 °C and 50% relative humidity for at least 17 weeks on a paper support to simulate a situation where a paper packaging is laminated with an oxygen barrier film of WG. The films, having target thicknesses of 50 and 250 μm, were characterized visually and with ultraviolet/visible and infrared spectroscopy; the mass loss was measured by gravimetry or by a glycerol-specific gas chromatography method. The thin films produced at pH 4 were, in general, more heterogeneous than those produced at pH 11. The thin pH 4 films consisted of transparent regions surrounding beige glycerol-rich regions, the former probably rich in gliadin and the latter rich in glutenin. This, together with less Maillard browning, meant that the thin pH 4 films, in contrast to the more homogeneous (beige) thin pH 11 films, showed good contact clarity. The variations in glycerol content did not significantly change the optical properties of the films. All the films showed a significant loss of glycerol to the paper support but, after almost 9 months, the thick pH 11 film containing initially 25 wt.% glycerol was still very flexible and, despite a better contact to the paper, had a higher residual glycerol content than the pH 4 film, which was also more brittle.
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| 21. |
- Cho, Sung-Woo, et al.
(author)
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Heat-sealing properties of compression-molded wheat gluten films
- 2007
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In: Journal of Biobased Materials and Bioenergy. - : American Scientific Publishers. - 1556-6560 .- 1556-6579. ; 1:1, s. 56-63
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Journal article (peer-reviewed)abstract
- The impulse heat-sealing properties of wheat gluten films were investigated. Films containing 30 wt% glycerol were compression molded at 100-130 °C and then sealed in a lap-shear or peel-test geometry at 120-175 °C. The tensile properties of the pristine films and the lap-shear and peel strength of the sealed films were evaluated and the seals were examined by scanning electron microscopy. Glycerol was added to the film surfaces prior to sealing in an attempt to enhance the seal strength. It was observed that the wheat gluten films were readily sealable. At a 120 °C sealing temperature and without glycerol as adhesive, the lap-shear strength was greater than or similar to that of polyethylene film, although the peel strength was poorer. The sealing temperature had a negligible effect on the lap-shear strength, but the peel strength increased with sealing temperature. The lap-shear strength increased with increasing mold temperature and the failure mode changed, especially in the absence of glycerol adhesive, from a cohesive (material failure) to an adhesive type. From previous results, it is known that the high-temperature (130 °C) compression-molded film was highly cross-linked and aggregated, and this prevents molecular interdiffusion and entanglement and thus leads to incomplete seal fusion and, in general, adhesive failure. The presence of glycerol adhesive had a beneficial affect on the peel strength but no, or only a minor, effect on the lap-shear strength.
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| 22. |
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| 23. |
- Cho, Sung-Woo, et al.
(author)
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Injection-molded nanocomposites and materials based on wheat gluten
- 2011
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In: International Journal of Biological Macromolecules. - : Elsevier BV. - 0141-8130 .- 1879-0003. ; 48:1, s. 146-152
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Journal article (peer-reviewed)abstract
- This is, to our knowledge, the first study of the injection molding of materials where wheat gluten (WG) is the main component. In addition to a plasticizer (glycerol), 5 wt.% natural montmorillonite clay was added. X-ray indicated intercalated clay and transmission electron microscopy indicated locally good clay platelet dispersion. Prior to feeding into the injection molder, the material was first compression molded into plates and pelletized. The filling of the circular mold via the central gate was characterized by a divergent flow yielding, in general, a stronger and stiffer material in the circumferential direction. It was observed that 20–30 wt.% glycerol yielded the best combination of processability and mechanical properties. The clay yielded improved processability, plate homogeneity and tensile stiffness. IR spectroscopy and protein solubility indicated that the injection molding process yielded a highly aggregated structure. The overall conclusion was that injection molding is a very promising method for producing WG objects.
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| 24. |
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| 25. |
- Cho, Sung-Woo, et al.
(author)
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Properties of Wheat Gluten/Poly(lactic acid) Laminates
- 2010
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In: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 58:12, s. 7344-7350
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Journal article (peer-reviewed)abstract
- Laminates of compression-molded glycerol-plasticized wheat gluten (WG) films surrounded and supported by poly(lactic acid) (PLA) films have been produced and characterized. The objective was to obtain a fully renewable high gas barrier film with sufficient mechanical integrity to function in, for example, extrusion-coating paper/board applications. It was shown that the lamination made it possible to make films with a broad range of glycerol contents (0-30 wt %) with greater strength than single unsupported WG films. The low plasticizer contents yielded laminates with very good oxygen barrier properties. In addition, whereas the unsupported WO films had an immeasurably high water vapor transmission rate (WVTR), the laminate showed values that were finite and surprisingly, in several cases, also lower than that of PLA. Besides being a mechanical support (as evidenced by bending and tensile data) and a shield between the WG and surrounding moisture, the PLA layer also prevented the loss of the glycerol plasticizer from the WG layer. This was observed after the laminate had been aged on an "absorbing" blotting paper for up to 17 weeks. The interlayer adhesion (peel strength) decreased with decreasing glycerol content and increasing WG film molding temperature (130 degrees C instead of 110 degrees C). The latter effect was probably due to a higher protein aggregation, as revealed by infrared spectroscopy. The lamination temperature (110-140 degrees C) did not, however, have a major effect on the final peel strength.
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| 26. |
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| 27. |
- Cho, Sung-Woo, et al.
(author)
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Wheat Gluten-Laminated Paperboard with Improved Moisture Barrier Properties : A New Concept Using a Plasticizer (Glycerol) Containing a Hydrophobic Component (Oleic Acid)
- 2012
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In: International Journal of Polymer Science. - : Hindawi Limited. - 1687-9422 .- 1687-9430. ; , s. 454359-
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Journal article (peer-reviewed)abstract
- This paper presents a novel approach to reduce the water vapor transmission rate (WVTR) and water absorbance of wheat gluten/paperboard laminates by introducing a hydrophobic component (oleic acid (OA)) into the hydrophilic plasticizer (glycerol). Whereas the paperboard showed immeasurably high WVTR, the laminate with gluten/glycerol yielded finite values. More importantly, by incorporating 75wt.% OA into the plasticizer, the WVTR and water absorbance were reduced by, respectively, a factor of three and 1.5-2. Of particular interest was that the mechanical properties were not changing dramatically between 0 and 50 wt.% OA. The results showed clear benefits of combining a gluten film with paperboard. Whereas the paperboard provided toughness, the WG layer contributed with improved moisture barrier properties. In addition, WVTR indicated that the paperboard reduced the swelling of the outer gluten/glycerol layer in moist conditions; a free standing gluten/glycerol film would yield infinite, rather than finite, WVTR values.
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| 28. |
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| 29. |
- Gallstedt, Mikael, et al.
(author)
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Film Extrusion of Crambe abyssinica/Wheat Gluten Blends
- 2017
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In: Journal of Visualized Experiments. - : JOURNAL OF VISUALIZED EXPERIMENTS. - 1940-087X. ; :119
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Journal article (peer-reviewed)abstract
- Crambe abyssinica is a plant with potential for use in industrial (non-food) plant oil production. The side stream from this oil production is a high-protein crambe meal that has limited value, as it is not fit for food or feed use. However, it contains proteins that could potentially make it a suitable raw material for higher-value products. The purpose of this study was to find methods of making this side stream into extruded films, showing that products with a higher value can be produced. The study mainly considered the development of material compositions and methods of preparing and extruding the material. Wheat gluten was added as a supportive protein matrix material, together with glycerol as a plasticizer and urea as a denaturant. The extrudate was evaluated with respect to mechanical (tensile testing) and oxygen barrier properties, and the extrudate structure was revealed visually and by scanning electron microscopy. A denser, more homogeneous material had a lower oxygen transmission rate, higher strength, and higher extensibility. The most homogeneous films were made at an extruder die temperature of 125-130 degrees C. It is shown here that a film can be extruded with promising mechanical and oxygen barrier properties, the latter especially after a final compression molding step.
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| 30. |
- Gedde, Ulf W, et al.
(author)
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Mass and charge transport in polyethylene – Structure, morphology and properties
- 2023
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In: Polymer. - : Elsevier BV. - 0032-3861 .- 1873-2291. ; 266
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Research review (peer-reviewed)abstract
- Polyethylene is a model for semicrystalline polymers that provides the option to vary crystallinity within wide ranges and then to establish relationships between structure and mass and charge transport properties. Three different topics are covered: diffusion of n-hexane in polyethylene, extensive penetrant uptake kinetics, swelling and the design of a novel sensor, and finally electrical conduction in polyethylene, a field important to modern distribution of electric power (HVDC). This feature article presents past and ongoing studies at KTH Royal Institute of Technology using a variety of experimental methods and computer-aided simulation and modelling.
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| 31. |
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| 32. |
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| 33. |
- Hedenqvist, Mikael S., et al.
(author)
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Barrier properties of SiOx-coated polymers : multi-layer modelling and effects of mechanical folding
- 2003
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In: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 172:1, s. 7-12
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Journal article (peer-reviewed)abstract
- The oxygen permeability properties of poly(ethylene terephthalate), low- and high-density polyethylenes and polypropylene coated with SiOx using cold plasma were studied. A previously developed computer model for the calculation of transport properties in laminates containing very different layer thickness was fitted to experimental permeability data to obtain the oxygen transport properties of the SiOx coating. For the first time, to the best of our knowledge, it was possible to obtain the oxygen diffusivity and solubility of a SiOx coating on a polymer substrate. The effects of folding the laminates through 90degrees on the permeability properties of the SiOx coating were also investigated. The surface roughness of the substrates was obtained by atomic force microscopy and the morphology of the laminate surfaces was analysed by scanning electron microscopy. The oxygen diffusivity and solubility of a 45-nm-thick SiOx coating deposited on a 4000-fold thicker polypropylene substrate were 5 x 10(-12) cm(2) s(-1) and 0.72 cm(2) (STP) cm(-3) atm(-1), respectively. The diffusivity was approximately four orders of magnitude lower than that of the polymer substrate and, surprisingly, the solubility was higher than that of the polypropylene film. A hypothesis to explain these results is that the coating contained voids and, according to the permeability time lag, these were not continuous through the coating. The oxygen permeability of the coating increased with increasing substrate surface roughness, and was consequently lowest for poly(ethylene terephthalate). The folding operation initiated cracks in the coating, and the resulting increase in oxygen permeability was greater in the rougher substrates.
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| 34. |
- Hedenqvist, Mikael S., et al.
(author)
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Extrusion of protein plastics
- 2017
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In: Abstracts of Papers of the American Chemical Society. - : American Chemical Society (ACS). - 0065-7727. ; 253
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Journal article (other academic/artistic)
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| 35. |
- Henrik Ullsten, N., et al.
(author)
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Extruded high quality materials from wheat gluten
- 2010
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In: Polymers from Renewable Resources. - : SAGE Publications. - 2041-2479 .- 2045-1377. ; 1:4, s. 173-186
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Journal article (peer-reviewed)abstract
- In this study, we report that the addition of ammonium hydroxide (NH4OH)significantly enhance the properties of extruded WG-based materials. The grainystructure disappeared and the extrudate became more uniform and glossy. Thebarrier properties improved and the oxygen permeability at dry conditions was aslow as that for a number of petroleum-based plastics (poly(ethylene terephthalateand polyamide 66). The protein structure in this material was extensivelyaggregated, which improved the strength and stiffness; there was a ca 4-foldincrease in maximum stress compared to that of the NH4OH-free samples. Theprotein solubility decreased to almost zero. Even a severe sonication treatmentin sodium dodecyl sulphate (SDS) did not increase the solubility. The only typeof protein that it was possible to extract was the 'thermo-resistant' w-gliadinslacking disulfide-bonds. Our result provides new opportunities to develop a WGbasedfilm extrudate for potential use as e.g. a renewable barrier layer in foodand non-food laminate packagings.
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| 36. |
- Holder, Shima L., et al.
(author)
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Solubility and Diffusivity of Polar and Non-Polar Molecules in Polyethylene-Aluminum Oxide Nanocomposites for HVDC Applications
- 2020
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In: Energies. - : MDPI AG. - 1996-1073. ; 13:3, s. 722-
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Journal article (peer-reviewed)abstract
- The best commercial high-voltage insulation material of today is (crosslinked) ultra-pure low-density polyethylene (LDPE). A 100-fold decrease in electrical conductivity can be achieved by adding 1–3 wt.% of well-dispersed inorganic nanoparticles to the LDPE. One hypothesis is that the nanoparticle surfaces attract ions and polar molecules, thereby cleaning the surrounding polymer, and thus reducing the conductivity. LDPE-based nanocomposites with 1–12 wt.% octyl-coated aluminum oxide nanoparticles were prepared and the sorption and desorption of one polar compound (acetophenone, a crosslinking by-product) and one non-polar compound of a similar size (limonene) were examined. Since the uptake of acetophenone increased linearly with increasing filler content, whereas the uptake of limonene decreased, the surface attraction hypothesis was strengthened. The analytical functions for predicting composite solubility as a function of particle size and filler fraction were derived using experimental solubility measurements and Monte Carlo simulations.
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| 37. |
- Jansson, S. E. A., et al.
(author)
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Packaging materials for fermented milk : Effects of material crystallinity and polarity on food quality
- 2001
-
In: Packaging technology & science. - : Wiley. - 0894-3214 .- 1099-1522. ; 14:3, s. 119-127
-
Journal article (peer-reviewed)abstract
- The ability of a packaging material to protect the food product and extend its shelf-life depends on several material properties. In this work the effects of material crystallinity and polarity on the quality of fermented milk were studied. The fermented milk is a high-quality Swedish product, similar to yoghurt. The quality of the food product was determined as a function of storage time by containing the liquid in pouches of different materials. The material crystallinity was varied by using very low-density polyethylene, high-density polyethylene and aluminium laminate as packaging materials. Aluminium was used on account of its '100%' gas-tightness. The polarity was varied by comparing an aliphatic polyketone with polyethylene of similar crystallinity. The carbon dioxide (CO2) and oxygen (O-2) contents in the headspace of the pouches were determined. The food quality was determined by measuring whey syneresis, viscosity and the content of desired Bifidobacteria, as well as of undesired yeast and mould. A trained taste panel determined the degree of acidity and of the sparkling taste. It was found that the content of CO2 increased and that of O-2 decreased in the pouches with increasing degree of crystallinity and increasing polarity. The sparkling taste of fermented milk was a clear function of the headspace CO2 content. The data presented here could thus be used to 'design' a package for a desired sparkling taste of the fermented milk by selecting a certain material crystallinity. Whey syneresis, viscosity and content of Bifidobacteria were found to be independent of pouch material. While the degree of whey syneresis and the viscosity increased with increasing storage time, the content of Bifidobacteria slowly decreased. The content of yeast and mould in the liquid was below the existing limit values for foodstuffs. The degrees of acidity and sparkling taste were highest for the liquids contained in aluminium and polyketone pouches, although the differences in acidulous taste between the various pouch materials were small.
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| 38. |
- Jansson, S. E. A., et al.
(author)
-
Packaging materials for fermented milk Part 2 : Solute-induced changes and effects of material polarity and thickness on food quality
- 2002
-
In: Packaging technology & science. - : Wiley. - 0894-3214 .- 1099-1522. ; 15:6, s. 287-300
-
Journal article (peer-reviewed)abstract
- This work is a continuation of the application of a developed methodology for the selection of packaging material for a specific food product, in this case the 'demanding' food product. fermented milk. The effects of different packaging material parameters on the quality of fermented milk were studied. Food quality after storage was determined as a function of material polarity and pouch thickness by storing the liquid in pouches of different materials. The material polarity was varied by using laminates with polyethylene, poly(ethylene-co-vinyl alcohol) with two different ethylene contents and an aliphatic polyketone. The effects of pouch thickness were studied using high-density polyethylene films of different thicknesses between 25 mum and 200 mum. The interactions between the milk product and the pouch material were analysed by oxygen and water permeability, gas chromatography-mass spectrometry and tensile testing. The CO2 and O-2 contents in the headspace of the pouches were determined. The food quality was determined by measuring whey syneresis and the contents of Bifidobacteria, Enterobacteriaceae, yeast and mould. A trained taste panel determined the sensory properties. The content of CO2, and consequently the sparkling taste, increased with increasing polarity and/or pouch thickness. The CO2 content was affected more easily by changes in material polarity than by changes in pouch thickness. The increase in whey syneresis and the decrease in Bifidobacteria content with time were independent Of material polarity and pouch thickness. The contents Of Enterobacteriaceae, yeast and mould in the liquid were always below existing limits for foodstuffs. A newly developed method was used by which the CO2 and 02 permeabilities of the pouch/packaging could be estimated, using the kinetics of the gas composition in the pouch headspace. Permeability values, as estimated by the method, revealed that the CO2 production and the O-2 consumption rates of the fermented milk were dependent on the CO2 and O-2 headspace concentrations. An increase in permeability, determined by conventional methods, suggested that both the non-polar and the polar polymers were plasticized by fermented milk. The plasticization was, however, modest and undetectable when the polyethylene tensile test data were analysed.
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| 39. |
- Kallio, Kai J., 1967-, et al.
(author)
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Ageing properties of car fuel-lines;accelerated testing in “close-to-real” service conditions
- 2010
-
In: Polymer testing. - : Elsevier. - 0142-9418 .- 1873-2348. ; 29:1, s. 41-48
-
Journal article (peer-reviewed)abstract
- The use of ethanol-based fuels and tougher restrictions on fuel emissions put a higher demand on car fuel-line (pipe) systems. In this context, it is important to be able to establish and predict properties based on measurements on pipes exposed to real or “close-to-real” environments. This paper presents a new method to age pipes in accelerated “close-to-real” conditions. In this method, the pipe is exposed to circulating fuel on the inside and to air on the outside. The method/equipment allows for non-destructive mechanical testing on “continuous” pipes. The usefulness of the ageing method/system was illustrated on polyamide-12 (PA12) pipes exposed to fuels with varying ethanol content at 50 °C and 110 °C for a maximum of, respectively, ca 3 years and 100 days. “Non-destructive” three-point bending as well as tensile testing was used to assess the ageing-induced changes in mechanical properties. The most conclusive information was that the lowest pipe extensibility (ductility) of dried, previously fuel-exposed pipes was observed at the end of the ageing periods and at the higher ethanol contents. In fact, optical microscopy showed that the tensile fractured pipes, exposed to 25/30 vol. % ethanol at 110 °C (100 h), showed no signs of macroscopic yielding. The trends were interpreted, based also on findings from previous work, as being due to the loss of plasticiser (possibly also PA12 monomers/oligomers) and material “degradation/annealing” processes, the latter involving possibly stabiliser issues.
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| 40. |
- Karlsson, G. E., et al.
(author)
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Determining limonene diffusion in molten polyethylene from within 0.1 mu s molecular dynamics trajectories
- 2002
-
In: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 35:19, s. 7453-7459
-
Journal article (peer-reviewed)abstract
- Molecular dynamics simulations of the diffusion of limonene into molten polyethylene were performed in order to explore the possibility of using atomistic simulations to predict the diffusion of larger solute molecules in polymers. The system contained 6000 anisotropic united atom methylene units with a molar mass of 84 000 g mol(-1). A united atom limonene molecule (C10H16) was introduced into the polyethylene matrix. Limonene trajectories were generated for 2-100. ns at 77-227 degreesC. The simulated diffusivities were compared with experimental zero-concentration diffusivities of limonene in natural rubber and ultrahigh molar mass polyethylene, obtained from desorption measurements in the same temperature range. The simulated diffusivities and activation energy were within 30%. and 16% of the experimental thermodynamic diffusivities and activation energies, respectively. The simulated average diffusivities, obtained from 10 trajectories, changed by only 33% when the simulation time was shortened from 100 ns to 500 ps. The limonene molecule vibrated in a cagelike fashion on a 1-2 ps scale, whereas on a larger time scale the jumping was liquidlike. The limonene molecule showed tumbling during its motion through the polyethylene matrix.
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| 41. |
- Karlsson, G. E., et al.
(author)
-
Physical properties of dense amorphous poly(vinyl alcohol) as revealed by molecular dynamics simulation
- 2002
-
In: Journal of Macromolecular Science, Part B. - 0022-2348 .- 1525-609X. ; B41:2, s. 185-206
-
Journal article (peer-reviewed)abstract
- Dense amorphous poly(vinyl alcohol) (PVAL) built from a chain with 145 repeating units was studied by constant number of particles, pressure, and temperature-molecular dynamics simulations at temperatures between 400 and 527K. The results of the simulations were compared with pressure-volume-temperature data, solubility parameter, x-ray scattering pattern, and data for the characteristic ratio. The fractional free-volume distribution was computed and the diffusion characteristics of water in the polymer were studied. Experimental water desorption data were obtained and they were compared with the results obtained from the simulations. The AMBER-force field was initially adopted to generate the dynamics, but this force field yielded structures with too high specific volumes. The size of the oxygen atoms was then decreased until the maximum difference between experimental and simulated specific volumes was within 2.2%. This modification of the force field resulted in satisfactory agreement between experimental and simulated data for the volume expansion coefficient and the compressibility in the temperature range from 402 to 502K. The essential features in the local packing of the atoms as revealed by wide-angle x-ray scattering were also present in the simulated structures. Simulated values for the characteristic ratio were in agreement with earlier reported experimental values. The solubility parameter showed only minor deviations from reported experimental values. Water-molecule trajectories yielded diffusivity in accordance with the experimental zero-concentration diffusivity. The water molecule makes well-resolved jumps (cage-like penetrant motion) even at the highest temperature of simulation, 510K. The water molecule rotates much faster than it makes jumps in the PVAL matrix. The lifetimes of the hydrogen bonds between polymer chain segments were longer than for those of the hydrogen bonds formed between water and polymer chain segments. This finding suggests that the primary rate-controlling factor for water diffusion in this polymer is the constraining effect of hydrogen bonds formed between polymer chain segments.
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| 42. |
- Kuktaite, Ramune, et al.
(author)
-
Changes in the hierarchical protein polymer structure : Urea and temperature effects on wheat gluten films
- 2012
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 2:31, s. 11908-11914
-
Journal article (peer-reviewed)abstract
- Understanding bio-based protein polymer structures is important when designing new materials with desirable properties. Here the effect of urea on the wheat gluten (WG) protein structure in WG-urea films was investigated. Small-angle X-ray scattering indicated the formation of a hexagonal close-packed (HCP) hierarchical structure in the WG-urea materials. The HCP structure was influenced significantly by the urea concentration and processing conditions. The interdomain distance d I between the HCP scattering objects increased with increasing content of urea and the objects seemed to be oriented in the extrusion direction. Additionally, the effect of temperature on the HCP structure was studied and it was shown that at ≥55°C the HCP structure disappeared. Transmission electron microscopy revealed a rather denatured pattern of both HMW-glutenins and gliadins in the WG-urea films. The molecular packing of the WG protein polymer can be highly affected by an additive and the processing method used.
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| 43. |
- Kuktaite, Ramune, et al.
(author)
-
Gluten biopolymer and nanoclay-derived structures in wheat gluten-urea-clay composites
- 2014
-
In: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 2:6, s. 1439-1445
-
Journal article (peer-reviewed)abstract
- Here, we investigated the structure of natural montmorillonite (MMT) and modified Cloisite C15A (MMT pre-intercalated with a dimethyl-dehydrogenated tallow quaternary ammonium surfactant) nanoclays in the wheat gluten-urea matrix in order to obtain a nanocomposite with improved barrier and mechanical properties. Small-angle X-ray scattering indicated that the characteristic hexagonal closed packed structure of the wheat gluten-urea matrix was not found in the C15A system and existed only in the 3 and 5 wt % MMT composites. SAXS/WAXS, TGA, and water vapor/oxygen barrier properties indicated that the dispersion of the C15A clay was somewhat better than the natural MMT clay. Confocal laser scanning microscopy showed MMT clay clusters and C15A clay particles dispersed in the protein matrix, and these were preferentially oriented in the extrusion direction only at 5 wt % of the C15 clay. The water vapor/oxygen barrier properties were improved with the presence of clay. Independent of the clay content used, the stiffness decreased and the extensibility increased in the presence of C15A due to the surfactant induced changes on the protein. The opposite "more expected" clay effect (increasing stiffness and decreasing extensibility) was observed for the MMT composites.
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| 44. |
- Kuktaite, Ramune, et al.
(author)
-
Gluten Biopolymer and Nanoclay-Derived Structures in Wheat Gluten-Urea-Clay Composites: Relation to Barrier and Mechanical Properties
- 2014
-
In: ACS Sustainable Chemistry & Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 2:6, s. 1439-1445
-
Journal article (peer-reviewed)abstract
- Here, we investigated the structure of natural montmorillonite (MMT) and modified Cloisite C15A (MMT pre-intercalated with a dimethyl-dehydrogenated tallow quaternary ammonium surfactant) nanoclays in the wheat gluten-urea matrix in order to obtain a nanocomposite with improved barrier and mechanical properties. Small-angle X-ray scattering indicated that the characteristic hexagonal closed packed structure of the wheat gluten-urea matrix was not found in the CISA system and existed only in the 3 and 5 wt % MMT composites. SAXS/WAXS, TGA, and water vapor/oxygen barrier properties indicated that the dispersion of the C15A clay was somewhat better than the natural MMT clay. Confocal laser scanning microscopy showed MMT clay clusters and C15A clay particles dispersed in the protein matrix, and these were preferentially oriented in the extrusion direction only at 5 wt % of the CIS clay. The water vapor/oxygen barrier properties were improved with the presence of clay. Independent of the clay content used, the stiffness decreased and the extensibility increased in the presence of C15A due to the surfactant induced changes on the protein. The opposite "more expected" clay effect (increasing stiffness and decreasing extensibility) was observed for the MMT composites.
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| 45. |
- Kuktaite, Ramune, et al.
(author)
-
Structure and Morphology of Wheat Gluten Films : From Polymeric Protein Aggregates toward Superstructure Arrangements
- 2011
-
In: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 12:5, s. 1438-1448
-
Journal article (peer-reviewed)abstract
- Evaluation of structure and morphology of extruded wheat gluten (WG) films showed WG protein assemblies elucidated on a range of length scales from nano (4.4 angstrom and 9 to 10 angstrom, up to 70 angstrom) to micro (10 mu m). The presence of NaOH in WG films induced a tetragonal structure with unit cell parameters, a = 51.85 angstrom and c = 40.65 angstrom, whereas NH4OH resulted in a bidimensional hexagonal close-packed (HCP) structure with a lattice parameter of 70 angstrom. In the WG films with NH4OH, a highly polymerized protein pattern with intimately mixed glutenins and gliadins bounded through SH/SS interchange reactions was found. A large content of beta-sheet structures was also found in these films, and the film structure was oriented in the extrusion direction. In conclusion, this study highlights complexities of the supramolecular structures and conformations of wheat gluten polymeric proteins in biofilms not previously reported for biobased materials.
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| 46. |
- Moyassari, Ali, et al.
(author)
-
First-principle simulations of electronic structure in semicrystalline polyethylene
- 2017
-
In: Journal of Chemical Physics. - : American Institute of Physics (AIP). - 0021-9606 .- 1089-7690. ; 146:20
-
Journal article (peer-reviewed)abstract
- In order to increase our fundamental knowledge about high-voltage cable insulation materials, realistic polyethylene (PE) structures, generated with a novel molecular modeling strategy, have been analyzed using first principle electronic structure simulations. The PE structures were constructed by first generating atomistic PE configurations with an off-lattice Monte Carlo method and then equilibrating the structures at the desired temperature and pressure using molecular dynamics simulations. Semicrystalline, fully crystalline and fully amorphous PE, in some cases including crosslinks and short-chain branches, were analyzed. The modeled PE had a structure in agreement with established experimental data. Linear-scaling density functional theory (LS-DFT) was used to examine the electronic structure (e.g., spatial distribution of molecular orbitals, bandgaps and mobility edges) on all the materials, whereas conventional DFT was used to validate the LS-DFT results on small systems. When hybrid functionals were used, the simulated bandgaps were close to the experimental values. The localization of valence and conduction band states was demonstrated. The localized states in the conduction band were primarily found in the free volume (result of gauche conformations) present in the amorphous regions. For branched and crosslinked structures, the localized electronic states closest to the valence band edge were positioned at branches and crosslinks, respectively. At 0 K, the activation energy for transport was lower for holes than for electrons. However, at room temperature, the effective activation energy was very low (similar to 0.1 eV) for both holes and electrons, which indicates that the mobility will be relatively high even belowthe mobility edges and suggests that charge carriers can be hot carriers above the mobility edges in the presence of a high electrical field.
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| 47. |
- Muneer, Faraz, et al.
(author)
-
Impact of pH Modification on Protein Polymerization and Structure-Function Relationships in Potato Protein and Wheat Gluten Composites
- 2019
-
In: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 20:1
-
Journal article (peer-reviewed)abstract
- Wheat gluten (WG) and potato protein (PP) were modified to a basic pH by NaOH to impact macromolecular and structural properties. Films were processed by compression molding (at 130 and 150 degrees C) of WG, PP, their chemically modified versions (MWG, MPP) and of their blends in different ratios to study the impact of chemical modification on structure, processing and tensile properties. The modification changed the molecular and secondary structure of both protein powders, through unfolding and re-polymerization, resulting in less cross-linked proteins. The beta-sheet formation due to NaOH modification increased for WG and decreased for PP. Processing resulted in cross-linking of the proteins, shown by a decrease in extractability; to a higher degree for WG than for PP, despite higher beta-sheet content in PP. Compression molding of MPP resulted in an increase in protein cross-linking and improved maximum stress and extensibility as compared to PP at 130 degrees C. The highest degree of cross-linking with improved maximum stress and extensibility was found for WG/MPP blends compared to WG/PP and MWG/MPP at 130 degrees C. To conclude, chemical modification of PP changed the protein structures produced under harsh industrial conditions and made the protein more reactive and attractive for use in bio-based materials processing, no such positive gains were seen for WG.
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| 48. |
- Muneer, Faraz, et al.
(author)
-
Nanostructural Morphology of Plasticized Wheat Gluten and Modified Potato Starch Composites: Relationship to Mechanical and Barrier Properties
- 2015
-
In: Biomacromolecules. - : American Chemical Society (ACS). - 1526-4602 .- 1525-7797. ; 16:3, s. 695-705
-
Journal article (peer-reviewed)abstract
- In the present study, we were able to produce composites of wheat gluten (WG) protein and a novel genetically modified potato starch (MPS) with attractive mechanical and gas barrier properties using extrusion. Characterization of the MPS revealed an altered chain length distribution of the amylopectin fraction and slightly increased amylose content compared to wild type potato starch. WG and MPS of different ratios plasticized with either glycerol or glycerol and water were extruded at 110 and 130 °C. The nanomorphology of the composites showed the MPS having semicrystalline structure of a characteristic lamellar arrangement with an approximately 100 Å period observed by small-angle X-ray scattering and a B-type crystal structure observed by wide-angle X-ray scattering analysis. WG has a structure resembling the hexagonal macromolecular arrangement as reported previously in WG films. A larger amount of β-sheets was observed in the samples 70/30 and 30/70 WG-MPS processed at 130 °C with 45% glycerol. Highly polymerized WG protein was found in the samples processed at 130 °C versus 110 °C. Also, greater amounts of WG protein in the blend resulted in greater extensibility (110 °C) and a decrease in both E-modulus and maximum stress at 110 and 130 °C, respectively. Under ambient conditions the WG-MPS composite (70/30) with 45% glycerol showed excellent gas barrier properties to be further explored in multilayer film packaging applications.
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| 49. |
- Muneer, Faraz, et al.
(author)
-
Preparation, Properties, Protein Cross-Linking and Biodegradability of Plasticizer-Solvent Free Hemp Fibre Reinforced Wheat Gluten, Glutenin, and Gliadin Composites
- 2014
-
In: BioResources. - : BioResources. - 1930-2126. ; 9:3, s. 5246-5261
-
Journal article (peer-reviewed)abstract
- The present study is aimed at evaluating the use of plant-based polymers and fibres for the production of sustainable biocomposites. For the first time, plasticiser/solvent-free hemp fibre-reinforced wheat gluten and hemp-gliadin and glutenin composites were obtained by compression moulding at different temperatures. The plasticiser/solvent-free sample preparation method developed in this study facilitated the use of a powdered protein matrix with a mat of randomly oriented hemp fibres. The tensile and protein cross-linking properties, as well as the biodegradability, were investigated. The addition of hemp fibre to the protein matrix increased the E-modulus by 20 to 60% at 130 degrees C. An increase in moulding temperature from 110 to 130 degrees C resulted in an increase in maximum stress due to the formation of intermolecular bonds between protein chains. The gliadin composites had higher E-modulus and maximum stress and showed a larger increase in protein polymerisation with increased temperature compared to the gluten in composites. A comparison of tensile properties revealed that the composites were stiffer and stronger compared to several similarly produced biobased composites. The composites were found to be fully biodegradable under a simulated soil environment after 180 days. Biocomposites produced in the present study were found to be environmentally friendly with fairly good mechanical properties.
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| 50. |
- Muneer, Faraz, et al.
(author)
-
The impact of newly produced protein and dietary fiber rich fractions of yellow pea (Pisum sativum L.) on the structure and mechanical properties of pasta-like sheets
- 2018
-
In: Food Research International. - : Elsevier. - 0963-9969 .- 1873-7145. ; 106, s. 607-618
-
Journal article (peer-reviewed)abstract
- Two fractions from pea (Pisum sativum L.), protein isolate (PPI) and dietary fiber (PF), were newly produced by extraction-fractionation method and characterized in terms of particle size distribution and structural morphology using SEM. The newly produced PPI and PF fractions were processed into pasta-like sheets with varying protein to fiber ratios (100/0, 90/10, 80/20, 70/30 and 50/50, respectively) using high temperature compression molding. We studied protein polymerization, molecular structure and protein-fiber interactions, as well as mechanical performance and cooking characteristics of processed PPI-PF blends. Bi-modal particle size distribution and chemical composition of the PPI and PF fractions influenced significantly the physicochemical properties of the pasta-like sheets. Polymerization was most pronounced for the 100 PPI, 90/10 and 80/20 PPI-PF samples as studied by SE-HPLC, and polymerization decreased with addition of the PF fraction. The mechanical properties, as strength and extensibility, were likewise the highest for the 100 PPI and 90/10 PPI-PF blends, while the E-modulus was similar for all the studied blends (around 38 MPa). The extensibility decreased with the increasing amount of PF in the blend. The highest amounts of beta-sheets were found in the pasta-like sheets with high amounts of PPI (100, 90 and 80%), by FT-IR. An increase in PF fraction in the blend, resulted into the high amounts of unordered structures as observed by FT-IR, as well as in an increase in the molecular scattering distances observed by SAXS. The water uptake increased and cooking loss decreased with increased proportions of the PF fraction, and the consistency of 10 min cooked pasta-like sheets were alike al dente texture. The new knowledge obtained in this study on the use of extraction-fractionation method to produce novel PPI and PF fractions for developing innovative high nutritious food can be of a great importance. The obtained knowledge on the pea protein and fiber processing behaviour could greatly contribute to a better control of functional properties of various temperature-processed products from yellow pea.
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