| 1. |
- Birdsong, Björn K., et al.
(författare)
-
Large-scale synthesis of 2D-silica (SiOx) nanosheets using graphene oxide (GO) as a template material
- 2023
-
Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 15:31, s. 13037-13048
-
Tidskriftsartikel (refereegranskat)abstract
- Graphene oxide (GO) was used in this study as a template to successfully synthesize silicon oxide (SiOx) based 2D-nanomaterials, adapting the same morphological features as the GO sheets. By performing a controlled condensation reaction using low concentrations of GO (<0.5 wt%), the study shows how to obtain 2D-nanoflakes, consisting of GO-flakes coated with a silica precursor that were ca. 500 nm in lateral diameter and ca. 1.5 nm in thickness. XPS revealed that the silanes had linked covalently with the GO sheets at the expense of the oxygen groups present on the GO surface. The GO template was shown to be fully removable through thermal treatment without affecting the nanoflake morphology of the pure SiOx-material, providing a methodology for large-scale preparation of SiOx-based 2D nanosheets with nearly identical dimensions as the GO template. The formation of SiOx sheets using a GO template was investigated for two different silane precursors, (3-aminopropyl) triethoxysilane (APTES) and tetraethyl orthosilicate (TEOS), showing that both precursors were capable of accurately templating the graphene oxide template. Molecular modeling revealed that the choice of silane affected the number of layers coated on the GO sheets. Furthermore, rheological measurements showed that the relative viscosity was significantly affected by the specific surface area of the synthesized particles. The protocol used showed the ability to synthesize these types of nanoparticles using a common aqueous alcohol solvent, and yield larger amounts (∼1 g) of SiOx-sheets than what has been previously reported.
|
|
| 2. |
- Capezza, Antonio Jose, et al.
(författare)
-
Biodegradable Fiber-Reinforced Gluten Biocomposites for Replacement of Fossil-Based Plastics
- 2023
-
Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 9:1, s. 1341-1351
-
Tidskriftsartikel (refereegranskat)abstract
- Biocomposites based on wheat gluten and reinforced with carbon fibers were produced in line with the strive to replace fossil-based plastics with microplastic-free alternatives with competing mechanical properties. The materials were first extruded/compounded and then successfully injection molded, making the setup adequate for the current industrial processing of composite plastics. Furthermore, the materials were manufactured at very low extrusion and injection temperatures (70 and 140 degrees C, respectively), saving energy compared to the compounding of commodity plastics. The sole addition of 10 vol % fibers increased yield strength and stiffness by a factor of 2-4 with good adhesion to the protein. The biocomposites were also shown to be biodegradable, lixiviating into innocuous molecules for nature, which is the next step in the development of sustainable bioplastics. The results show that an industrial protein coproduct reinforced with strong fibers can be processed using common plastic processing techniques. The enhanced mechanical performance of the reinforced protein-based matrix herein also contributes to research addressing the production of safe materials with properties matching those of traditional fossil-based plastics.
|
|
| 3. |
- Perez-Puyana, Victor M., et al.
(författare)
-
Functionalization Routes for Keratin from Poultry Industry Side-Streams-Towards Bio-Based Absorbent Polymers
- 2023
-
Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 15:2, s. 351-
-
Tidskriftsartikel (refereegranskat)abstract
- Keratin is a largely available protein that can be obtained from the ca. 3 million tons of feathers that the European poultry industry produces as a side-stream. Here, the functionalization of keratin from poultry feathers was evaluated using a one- versus two-stage process using two functionalization agents (succinic anhydride-SA and ethylene dianhydride-EDTAD). The functionalization resulted in the keratin having improved liquid swelling capacities, reaching up to 400%, 300%, and 85% increase in water, saline, and blood, respectively, compared to non-functionalized keratin. The highest swelling was obtained for samples functionalized with EDTAD (one-stage process), while the highest saline uptake was noted for samples processed with 25 wt% SA (two-stage process). Swelling kinetics modeling indicated that the water uptake by the functionalized samples takes place in two steps, and the EDTAD samples showed the highest diffusivity. It is demonstrated that the one-stage functionalization of keratin utilizing EDTAD results in better performance than two-stages, which allows for resource-saving and, thereby, protecting the environment. The results show some potential for the keratin to be utilized as liquid absorbent materials in water, saline, and blood uptake applications. Using keratin from side-streams is an advantage from a sustainability perspective over biomacromolecules that need to be extracted from virgin biomass.
|
|
| 4. |
- Capezza, Antonio Jose, et al.
(författare)
-
Greenhouse gas emissions of biobased diapers containing chemically modified protein superabsorbents
- 2023
-
Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 387
-
Tidskriftsartikel (refereegranskat)abstract
- Replacing the current mainly fossil-based, disposable, and non-biodegradable sanitary products with sustainable, functional alternatives is an industry priority. Suggested biobased alternatives require evaluation of their actual impact on greenhouse gas (GHG) emissions. We evaluated GHG emissions of biobased baby diapers as the most consumed sanitary product, using a biodegradable functionalized protein superabsorbent polymer (bioSAP) and compared them with currently used fossil-based counterparts. Assessment of the diapers also included estimated GHG emissions from the production of the biobased components, transport, and end-of-life combustion of these items. It was shown that only a few of the biobased diaper alternatives resulted in lower GHG emissions than commercial diapers containing fossil-based materials. At the same time, it was demonstrated that the production of the bioSAP via chemical modification of a protein raw material is the primary GHG contributor, with 78% of the total emissions. Reduction of the GHG contribution of the bioSAP production was achieved via a proposed recycling route of the functionalization agent, reducing the GHG emissions by 13% than if no recycling was carried out. Overall, we demonstrated that reduced and competitive GHG emissions could be achieved in sanitary articles using biobased materials, thereby contributing to a sanitary industry producing disposable products with less environmental pollution while allowing customers to keep their current consumption patterns.
|
|
| 5. |
- Guo, Boyang, et al.
(författare)
-
Fast Depolymerization of PET Bottle Mediated by Microwave Pre-Treatment and An Engineered PETase
- 2023
-
Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 16:18
-
Tidskriftsartikel (refereegranskat)abstract
- Recycling plastics is the key to reaching a sustainable materials economy. Biocatalytic degradation of plastics shows great promise by allowing selective depolymerization of man-made materials into constituent building blocks under mild aqueous conditions. However, insoluble plastics have polymer chains that can reside in different conformations and show compact secondary structures that offer low accessibility for initiating the depolymerization reaction by enzymes. In this work, we overcome these shortcomings by microwave irradiation as a pre-treatment process to deliver powders of polyethylene terephthalate (PET) particles suitable for subsequent biotechnology-assisted plastic degradation by previously generated engineered enzymes. An optimized microwave step resulted in 1400 times higher integral of released terephthalic acid (TPA) from high-performance liquid chromatography (HPLC), compared to original untreated PET bottle. Biocatalytic plastic hydrolysis of substrates originating from PET bottles responded to 78 % yield conversion from 2 h microwave pretreatment and 1 h enzymatic reaction at 30 °C. The increase in activity stems from enhanced substrate accessibility from the microwave step, followed by the administration of designer enzymes capable of accommodating oligomers and shorter chains released in a productive conformation.
|
|
| 6. |
- Jugé, Agnès, et al.
(författare)
-
Porous Thermoformed Protein Bioblends as Degradable Absorbent Alternatives in Sanitary Materials
- 2023
-
Ingår i: ACS Applied Polymer Materials. - : American Chemical Society (ACS). - 2637-6105. ; 5:9, s. 6976-6989
-
Tidskriftsartikel (refereegranskat)abstract
- Protein-based porous absorbent structures can be processed and assembled into configurations suitable for single-use, biodegradable sanitary materials. In this work, a formulation based on a mixture of proteins available as industrial coproducts is processed into continuous porous structures using extrusion and assembled using conventional thermal methods. The experimental design led to formulations solely based on zein-gluten protein bioblends that could be manufactured as liquid absorbent pellets, compressed pads, and/or porous films. The processing versatility is attributed to the synergistic effect of zein as a low viscosity thermoformable protein with gluten as a readily cross-linkable high molecular weight protein. The capillary-driven sorption, the biodegradability of the materials, and the possibility to assemble the products as multilayer components provide excellent performance indicators for their use as microplastic-free absorbents. This work shows the potential of biopolymers for manufacturing sustainable alternatives to current nonbiodegradable and highly polluting disposable items such as pads and diapers.
|
|
| 7. |
- Liu, Sirui, et al.
(författare)
-
Design of Hygroscopic Bioplastic Products Stable in Varying Humidities
- 2023
-
Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 308:2
-
Tidskriftsartikel (refereegranskat)abstract
- Hygroscopic biopolymers like proteins and polysaccharides suffer from humidity-dependent mechanical properties. Because humidity can vary significantly over the year, or even within a day, these polymers will not generally have stable properties during their lifetimes. On wheat gluten, a model highly hygroscopic biopolymer material, it is observed that larger/thicker samples can be significantly more mechanically stable than thinner samples. It is shown here that this is due to slow water diffusion, which, in turn, is due to the rigid polymer structure caused by the double-bond character of the peptide bond, the many bulky peptide side groups, and the hydrogen bond network. More than a year is required to reach complete moisture saturation (≈10 wt.%) in a 1 cm thick plate of glycerol-plasticized wheat gluten, whereas this process takes only one day for a 0.5 mm thick plate. The overall moisture uptake is also retarded by swelling-induced mechanical effects. Hence, hygroscopic biopolymers are better suited for larger/thicker products, where the moisture-induced changes in mechanical properties are smeared out over time, to the extent that the product remains sufficiently tough over climate changes, for example, throughout the course of a year.
|
|
| 8. |
- Newson, William, et al.
(författare)
-
Green Chemistry to Modify Functional Properties of Crambe Protein Isolate-Based Thermally Formed Films
- 2023
-
Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 8:23, s. 20342-20351
-
Tidskriftsartikel (refereegranskat)abstract
- Proteins are promising precursors to be used in production of sustainable materials with properties resembling plastics, although protein modification or functionalization is often required to obtain suitable product characteristics. Here, effects of protein modification were evaluated by crosslinking behavior using high-performance liquid chromatography (HPLC), secondary structure using infrared spectroscopy (IR), liquid imbibition and uptake, and tensile properties of six crambe protein isolates modified in solution before thermal pressing. The results showed that a basic pH (10), especially when combined with the commonly used, although moderately toxic, crosslinking agent glutaraldehyde (GA), resulted in a decrease in crosslinking in unpressed samples, as compared to acidic pH (4) samples. After pressing, a more crosslinked protein matrix with an increase in β-sheets was obtained in basic samples compared to acidic samples, mainly due to the formation of disulfide bonds, which led to an increase in tensile strength, and liquid uptake with less material resolved. A treatment of pH 10 + GA, combined either with a heat or citric acid treatment, did not increase crosslinking or improve the properties in pressed samples, as compared to pH 4 samples. Fenton treatment at pH 7.5 resulted in a similar amount of crosslinking as the pH 10 + GA treatment, although with a higher degree of peptide/irreversible bonds. The strong bond formation resulted in lack of opportunities to disintegrate the protein network by all extraction solutions tested (even for 6 M urea + 1% sodium dodecyl sulfate + 1% dithiothreitol). Thus, the highest crosslinking and best properties of the material produced from crambe protein isolates were obtained by pH 10 + GA and pH 7.5 + Fenton, where Fenton is a greener and more sustainable solution than GA. Therefore, chemical modification of crambe protein isolates is effecting both sustainability and crosslinking behavior, which might have an effect on product suitability.
|
|
| 9. |
- Sajjad, Anila, et al.
(författare)
-
Integration of Zinc Oxide Nanoparticles in Wheat Gluten Hydrolysates-Development of Multifunctional Films with Pliable Properties
- 2023
-
Ingår i: Journal of Inorganic and Organometallic Polymers and Materials. - : Springer Nature. - 1574-1443 .- 1574-1451. ; 33:4, s. 914-929
-
Tidskriftsartikel (refereegranskat)abstract
- Biodegradable wheat gluten hydrolysates (WGH) and zinc oxide nanoparticles (ZNPs) with cross-linkers were prepared as nanocomposite films. The physiochemical analysis demonstrated the formation of ZNPs of size approximately 18.37 nm with spherical and hexagonal nanostructures. The ZNPs are endowed with different functional groups, as corroborated by X-ray diffractogram (XRD), field emission electron microscopy (FE-SEM), and fourier transform infrared spectroscopy (FT-IR), respectively. XRD and functional group patterns (IR) of WG and ZNPs exhibited minor changes during film development, indicating a successful interaction between the components. The SEM analysis revealed that the integration of ZNPs into the wheat gluten polymer promoted nano-aggregation on the film surface and the cross-section. The swelling capacity of films was found to be highest by WG/PVP/ZNPs with 265% (pH 7) and 198% (at pH 9). The antibacterial assessments revealed the sensitivity of Pseudomonasaeruginosa and E.coli toward WG/PVP/ZNPs with 14 and 13 mm zone of inhibition, demonstrating the maximum release of zinc ions from WG/PVP/ZNPs films. Furthermore, the WG/PVP/ZNPs film exhibits maximum oxidant scavenging (84%) and oxidant quenching potential (75%). The findings suggest that casting of WGH with ZNPs has a remarkable effect on the films’ physical and biological properties, allowing for their potential use as future bioplastics in biomedical and industrial sectors.
|
|
| 10. |
- Sajjad, Anila, et al.
(författare)
-
Wheat gluten hydrolysates with embedded Ag-nanoparticles; a structure-function assessment for potential applications as wound sorbents with antimicrobial properties
- 2023
-
Ingår i: Polymer testing. - : Elsevier BV. - 0142-9418 .- 1873-2348. ; 118
-
Tidskriftsartikel (refereegranskat)abstract
- Numerous approaches have been used to prevent bacterial infection from injured skin, such as bandages and topical creams. However, the higher level of reactive oxygen species, bacterial infections, and excess wound exudates remain the major challenges for wound healing. In this study, we have tailored the structure of wheat gluten hydrolysates (WGH) as a continuous matrix by compositing it with a minimal amount of PVA, PVP, and PEG as polymer crosslinkers (0.5 wt%) to provide film structure integrity. Silver nanoparticles (AgNPs) were impregnated into the WGH to develop a control release matrix of the AgNPs. Scanning electron microscopy, X-ray diffractogram, and functional group patterns of WG and AgNPs indicate a successful integration of AgNPs into the wheat gluten matrix. The swelling capacity of the films was tested at acidic, neutral, and basic pH and was found to be highest in WG/PEG/Ag at pH 9 with 389%. The gradual release of Ag+/AgNPs from the films significantly scavenged free radicals and increased the antibacterial activity with up to a 12 mm inhibition zone against Pseudomonas aeruginosa. According to these findings, WGH with AgNPs has been successfully cast in films with increased absorption capacity, free radicals scavenging, oxidant quenching, and antibacterial capabilities, along with the sustained release of silver ions. The results, therefore, show the potential of the developed films in biomedical applications such as wound dressing.
|
|
