| 1. |
- Alimohammadzadeh, Rana, et al.
(författare)
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Direct Organocatalytic Thioglycolic Acid Esterification of Cellulose Nanocrystals : A simple entry to click chemistry on the surface of nanocellulose
- 2022
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Ingår i: Carbohydrate Polymer Technologies and Applications. - : Elsevier BV. - 2666-8939. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- The mild and simple direct organocatalytic esterification of cellulose nanocrystals (CNC) and nanocellulose-based materials (e.g. foams and films) with thioglycolic acid (TGA) is disclosed. The transformation gives the corresponding thiol group (-SH) functionalized crystalline nanocellulose (CNC-SH) using simple, naturally occurring, and non-toxic organic acids (e.g. tartaric acid) as catalysts. We also discovered that the direct esterification of cellulose with TGA is autocatalytic (i.e. the TGA is catalyzing its own esterification). The introduction of the -SH functionality at the nanocellulose surface opens up for further selective applications. This was demonstrated by attaching organic catalysts and fluorescent molecules, which are useful as sensors, to the CNC-SH surface by thiol-ene click chemistry. Another application is to use the CNC-SH-based foam as a heterogeneous biomimetic reducing agent, which is stable during multiple recycles, for the copper-catalyzed alkyne-azide 1,3-dipolar cycloaddition (“click” reaction).
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| 2. |
- Ayalew, Bahiru Tsegaye, et al.
(författare)
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Thermoplastic lignocellulose materials : A review on recent advancement and utilities
- 2023
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Ingår i: Carbohydrate Polymer Technologies and Applications. - : Elsevier BV. - 2666-8939. ; 5
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Forskningsöversikt (refereegranskat)abstract
- Lignocellulosic biomass is the most abundantly available resource in nature. However, its potential as a replacement of oil in plastic production has not been fully exploited. To reduce the carbon footprint, the use of lignocellulose biomass to produce bio-based plastics is attracting increasing global interest. The aim of this review article is to systematically summarize the recent advancements of the development of lignocellulose materials that possess thermoplastic properties, meaning they can be processed/shaped by common plastic processing techniques. The approaches used for modification of lignocellulose biomass and the properties of the modified materials, as well as factors affecting the properties of these, are discussed. The regulatory aspects and policy directions of bio-based plastics, including thermoplastic lignocellulose, are also mentioned. Current challenges of producing thermoplastic lignocellulose and the way forward to solve this are also explored.
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| 3. |
- Das, Atanu Kumar
(författare)
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Bio-based composites from bagasse using carbohydrate enriched cross-bonding mechanism: A formaldehyde-free approach
- 2024
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Ingår i: Carbohydrate Polymer Technologies and Applications. - 2666-8939. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- In this study, cross-bonded self-binding and bone glue-bonded particleboards were manufactured from sugarcane (Saccharum officinarum L.) bagasse with different pre-treatments of particles. Six types of panels were manufactured from bagasse particles with and without bone glue. The physical, mechanical, and thermal properties of the panels were examined according to the standards. Fourier Transform Infrared (FTIR) spectroscopy and thermogravimetric analysis (TG) were performed to investigate the changes in the chemical bonds and thermal stability of the fabricated composites, respectively. It was found that cross-bonded bagasse self-binding (TC) and bone glue-bonded (T3) panels fabricated from non-boiled bagasse particles showed higher physical and mechanical properties compared to the other types of panels. Non-boiled bagasse particles with bone glue panels showed the highest mechanical properties, i.e., modulus of rupture (MOR = 26.22 MPa), modulus of elasticity (MOE = 4302 MPa), tensile strength = 8.35 MPa, and hardness = 1.72 MPa. TC and T3 panels also showed higher thermal stability compared to the other types of panels. A new peak at 3331-3334 cm-1 for the N-H stretching vibration in the FTIR analysis represents the presence of bone glue in the cross-bonded particleboards. Thus, this research advances the production of formaldehyde-free bagasse particleboard, introducing the cross-bonding technique and sustainable bone glue.
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| 4. |
- Islam, Md. Nazrul, et al.
(författare)
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Bio-based composites from bagasse using carbohydrate enriched cross-bonding mechanism : A formaldehyde-free approach
- 2024
-
Ingår i: Carbohydrate Polymer Technologies and Applications. - : Elsevier BV. - 2666-8939. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, cross-bonded self-binding and bone glue-bonded particleboards were manufactured from sugarcane (Saccharum officinarum L.) bagasse with different pre-treatments of particles. Six types of panels were manufactured from bagasse particles with and without bone glue. The physical, mechanical, and thermal properties of the panels were examined according to the standards. Fourier Transform Infrared (FTIR) spectroscopy and thermogravimetric analysis (TG) were performed to investigate the changes in the chemical bonds and thermal stability of the fabricated composites, respectively. It was found that cross-bonded bagasse self-binding (TC) and bone glue-bonded (T3) panels fabricated from non-boiled bagasse particles showed higher physical and mechanical properties compared to the other types of panels. Non-boiled bagasse particles with bone glue panels showed the highest mechanical properties, i.e., modulus of rupture (MOR = 26.22 MPa), modulus of elasticity (MOE = 4302 MPa), tensile strength = 8.35 MPa, and hardness = 1.72 MPa. TC and T3 panels also showed higher thermal stability compared to the other types of panels. A new peak at 3331-3334 cm-1 for the N-H stretching vibration in the FTIR analysis represents the presence of bone glue in the cross-bonded particleboards. Thus, this research advances the production of formaldehyde-free bagasse particleboard, introducing the cross-bonding technique and sustainable bone glue.
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| 5. |
- Jayarathna, Shishanthi, et al.
(författare)
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Development and characterization of biocomposite films using banana pseudostem, cassava starch and poly(vinyl alcohol): A sustainable packaging alternative
- 2024
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Ingår i: Carbohydrate Polymer Technologies and Applications. - 2666-8939. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- To meet the need for sustainable packaging, we introduce a novel biocomposite film consisting of banana pseudostem, cassava starch, and poly(vinyl alcohol). We aimed to evaluate the optimal biocomposite film composition, which is characteristic for packaging materials. Using the solvent casting method, we produced biocomposite films with varying proportions (10-40 % w/w) of the lignocellulosic component from both Sour and Ash Plantain banana pseudostems. The resulting biocomposite films were characterized for mechanical, chemical, thermal, water absorption, gas permeability, and morphological properties. At the 25 % lignocellulosic level, a notable drop (P < 0.05) in tensile strength and elongation was observed, while water absorption increased, and gas permeability decreased. Fourier Transform Infrared Spectroscopy analysis revealed insights into the structural attributes of lignocellulosic composites. Thermogravimetric analysis indicated an onset temperature of 120 degree celsius for thermal degradation, confirming the biocomposite's thermal stability. A fundamental discovery emerged with the optimal composition at a 30 % pseudostem powder inclusion, offering an exceptional balance of tensile strength, elongation at break, water absorption, and gas permeability. This breakthrough holds significant implications for eco-friendly biocomposite films, particularly in food packaging. Future work may be undertaken to further explore banana pseudostems' potential in creating biocomposite films with advanced functionalities and their broader applications, including characterizations.
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| 6. |
- Naserifar, Shirin, 1991, et al.
(författare)
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Cellulose gelation in aqueous hydroxide solutions by CO 2 (g): Fact and theory
- 2024
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Ingår i: Carbohydrate Polymer Technologies and Applications. - : Elsevier Ltd. - 2666-8939. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Understanding how the solvent structure affects the stability of the dissolved state and the following precipitation is important for designing future dissolution-coagulation systems for cellulose processing. In this study, two morpholinium hydroxides with different alkyl chain lengths, namely N,N-dimethylmorpholinium hydroxide (NDMMOH(aq)) and N‑butyl‑N-methyl morpholinium hydroxide (BMMorOH(aq)), were studied and compared with the previously thoroughly investigated cellulose solvent benzyltriemethylammonium hydroxide (Triton B(aq)) which is well-known for its superior ability to stabilize the dissolved state. Cellulose solutions in each solvent were characterized by NMR, flow and frequency sweeps, while cellulose coagulation by CO2(g) was followed by in situ FTIR, pH and temperature measurements. The coagulated systems were characterized by CP/MAS 13C NMR, flow, and frequency sweep measurements. Complementary molecular dynamic (MD) simulations were performed to gain a deeper insight into the observed gelation behavior. The intrinsic viscosity indicated more extended cellulose chains in the solvents with more hydrophobic moieties (Triton B and BMMorOH). Even though the course of coagulation did not show any significant differences during monitoring, both the properties of the obtained gels and the MD simulations indicated differences in formation and properties of the coagulated materials that could be related both to the choice of solvent and coagulant.
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| 7. |
- Schmitz, Eva, et al.
(författare)
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Altering the water holding capacity of potato pulp via structural modifications of the pectic polysaccharides
- 2021
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Ingår i: Carbohydrate Polymer Technologies and Applications. - : Elsevier BV. - 2666-8939. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Potato pulp is a low value agricultural side stream with great valorisation potential as prebiotic food ingredient. An interesting functionality different from other prebiotics is its high water holding capacity (WHC). This study aims at exploring the relationship between physical and enzymatic modifications in the potato pulp and its WHC. Different temperature treatments and storage conditions were found to have a great influence on the WHC, freezing decreasing the WHC the least (15%) compared to fresh pulp. Ultrasonication of frozen pulp increased its WHC by 32%, while it did not have an effect on fresh pulp. Of the various tested enzymes, only protease led to an increase in WHC of fresh pulp (by 48%). The WHC of frozen and dry pulp could not be positively influenced by enzymatic treatment. Structurally, the potato pulps with increased WHC exhibited a larger surface area and more flaky structure.
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| 8. |
- Tideland, Hannah, et al.
(författare)
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Bendable transparent films from cellulose nanocrystals–Study of surface and microstructure-property relationship
- 2023
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Ingår i: Carbohydrate Polymer Technologies and Applications. - 2666-8939. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- The presented work focuses on preparing transparent bendable films from nanocellulose. In comparison to cellulose nanofibrils and bacterial cellulose, nanocrystalline cellulose are shorter and have higher crystallinity (CI<95 %). Sulfated CNC (CNCIH-OSO3H) were prepared, and by changing their counter ions from H+ to Na+ and Et4N+ (Tetraethyl ammonium) flexible films were prepared with a strength of 70.5 MPa and 2.6 % elongation at break. The CNC suspensions showed excellent dispersibility in DI water with Zeta-potential (ζ) values > -35 mV. In the preparation of films, pre-sonication was key in improving the tensile strength and improved elongation (>30 % increase compared to films prepared without sonication) and hydrophobicity. The change of counter ion, H+ to Na+ or Et4N+, improved the thermal and mechanical properties of CNC films. The films were investigated with UV–Vis spectroscopy and optical polarized spectroscopy to explain the arrangement of nanocellulose crystals in correlation with the mechanical properties. The wettability of CNC samples was also studied and explained in detail. CNC from CelluForce was also studied as commercial reference samples. The modified CNC films have adequate properties for application in flexible electronics, energy storage, and biodegradable smart packaging.
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| 9. |
- Wennman, Maria, 1985-, et al.
(författare)
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Plastic-free chitosan and cellulose binder providing dry and wet strength to paper and nonwoven
- 2022
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Ingår i: Carbohydrate Polymer Technologies and Applications. - : Elsevier BV. - 2666-8939. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Chemically-bonded nonwoven is commonly used in single-use products, and are often composed of cellulose fibers with a fossil-based binder. To reduce the amount of plastic littering, we investigated a biobased and biodegradable binder consisting of polyelectrolyte complexes based on chitosan, carboxymethyl cellulose and citric acid. The binder significantly improved the mechanical properties of two different types of cellulosic fiber systems in both dry and wet states. The quality of the water used in the binder had a significant impact on the mechanical properties, especially in the dry state, indicating a beneficial effect by the presence of cations. It was shown that covalent bonds were formed during the low temperature drying, and that the amount of bonds increased with a high temperature curing. Electron microscopy and tensile data indicated that the binder acted as a joint between the fiber/fiber parts. The presented results enable a sustainable solution for the current plastic-based nonwoven industry.
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