| 1. |
- Bravo, L, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 2. |
- Tabiri, S, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 3. |
- Engel, Emile, et al.
(författare)
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Advances in the green chemistry of coordination polymer materials
- 2020
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Ingår i: Green Chemistry. - : Royal Society of Chemistry (RSC). - 1463-9262 .- 1463-9270. ; 22:12, s. 3693-3715
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Forskningsöversikt (refereegranskat)abstract
- Coordination polymers, including metal-organic frameworks, are a diverse class of materials with myriad properties and potential applications. However, a number of drawbacks have hindered the scaling up of such materials towards commercial applications. These include health and safety risks, environmental hazards, poor cost efficiency and sustainability shortfalls. In contrast to the systematic progress of organic green chemistry, which has contributed to improvements in the sustainability of chemical processing, the development of green chemistry in the context of coordination polymers has been fragmented and sporadic. This review describes advances in the use of green components: benign sustainable ligands and non-hazardous earth abundant metals. Additionally, solvent considerations, synthesis strategies for improved sustainability and the performance of coordination polymers relative to alternative competing materials are discussed.
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| 4. |
- Engel, Emile, et al.
(författare)
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Composite Hydrogel Spheroids Based on Cellulose Nanofibrils and Nanofibrous Chiral Coordination Polymer by Green Synthesis
- 2020
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Ingår i: Advanced Sustainable Systems. - : Wiley-VCH Verlag. - 2366-7486.
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Tidskriftsartikel (refereegranskat)abstract
- Cellulose-based hydrogels are promising sustainable materials for a variety of applications, including tissue engineering, water treatment, and drug delivery. However, the tailoring of diverse properties by efficient green chemistry methods is an ongoing challenge. Here, composite hydrogels of consistent spheroidal structure, incorporating TEMPO-oxidized cellulose nanofibrils and nanofibrous chiral Cu(II) aspartate coordination polymer, are presented. The hydrogels are prepared by a single-step procedure in aqueous media at ambient temperature and pressure, adhering to the principles of green chemistry. With a view to adapting this method for a variety of alternative coordination polymers (to tailor functional properties), the following critical factors for formation of robust composite hydrogel spheroids are identified: rheological properties of the primary matrix used for spheroidal hydrogel formation and coordination polymer self-assembly rate.
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| 5. |
- Householder, John Ethan, et al.
(författare)
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One sixth of Amazonian tree diversity is dependent on river floodplains
- 2024
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Ingår i: NATURE ECOLOGY & EVOLUTION. - 2397-334X.
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Tidskriftsartikel (refereegranskat)abstract
- Amazonia's floodplain system is the largest and most biodiverse on Earth. Although forests are crucial to the ecological integrity of floodplains, our understanding of their species composition and how this may differ from surrounding forest types is still far too limited, particularly as changing inundation regimes begin to reshape floodplain tree communities and the critical ecosystem functions they underpin. Here we address this gap by taking a spatially explicit look at Amazonia-wide patterns of tree-species turnover and ecological specialization of the region's floodplain forests. We show that the majority of Amazonian tree species can inhabit floodplains, and about a sixth of Amazonian tree diversity is ecologically specialized on floodplains. The degree of specialization in floodplain communities is driven by regional flood patterns, with the most compositionally differentiated floodplain forests located centrally within the fluvial network and contingent on the most extraordinary flood magnitudes regionally. Our results provide a spatially explicit view of ecological specialization of floodplain forest communities and expose the need for whole-basin hydrological integrity to protect the Amazon's tree diversity and its function.
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| 6. |
- Jain, Karishma, et al.
(författare)
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3D printable composites of modified cellulose fibers and conductive polymers and their use in wearable electronics
- 2023
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Ingår i: APPLIED MATERIALS TODAY. - : Elsevier BV. - 2352-9407. ; 30
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Tidskriftsartikel (refereegranskat)abstract
- There are many bioelectronic applications where the additive manufacturing of conductive polymers may be of use. This method is cheap, versatile and allows fine control over the design of wearable electronic devices. Nanocellulose has been widely used as a rheology modifier in bio-based inks that are used to print electrical components and devices. However, the preparation of nanocellulose is energy and time consuming. In this work an easy-to-prepare, 3D-printable, conductive bio-ink; based on modified cellulose fibers and poly(3,4-ethylene dioxythiophene) poly(styrene sulfonate) (PEDOT:PSS), is presented. The ink shows excellent printability, the printed samples are wet stable and show excellent electrical and electrochemical performance. The printed structures have a conductivity of 30 S/cm, high tensile strains (>40%), and specific capacitances of 211 F/g; even though the PEDOT:PSS only accounts for 40 wt% of the total ink composition. Scanning electron microscopy (SEM), wide-angle X-ray scattering (WAXS), and Raman spectroscopy data show that the modified cellulose fibers induce conformational changes and phase separation in PEDOT:PSS. It is also demonstrated that wearable supercapacitors and biopotential-monitoring devices can be prepared using this ink.
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| 7. |
- Lo Re, Giada, 1971, et al.
(författare)
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Melt processable cellulose fibres engineered for replacing oil-based thermoplastics
- 2023
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 458
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Tidskriftsartikel (refereegranskat)abstract
- If cellulosic materials are to replace materials derived from non-renewable resources, it is necessary to overcome intrinsic limitations such as fragility, permeability to gases, susceptibility to water vapour and poor three-dimensional shaping. Novel properties or the enhancement of existing properties are required to expand the applications of cellulosic materials and will create new market opportunities. Here we have overcome the well-known restrictions that impede melt-processing of high cellulose content composites. Cellulose fibres, partially derivatised to dialcohol cellulose, have been used to manufacture three-dimensional high-density materials by conventional melt processing techniques, with or without the addition of a thermoplastic polymer. This work demonstrates the use of melt processable chemically modified cellulose fibres in the preparation of a new generation of highly sustainable materials with tuneable properties that can be tailored for specific applications requiring complex three-dimensional parts.
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| 8. |
- Luize, Bruno Garcia, et al.
(författare)
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Geography and ecology shape the phylogenetic composition of Amazonian tree communities
- 2024
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Ingår i: JOURNAL OF BIOGEOGRAPHY. - 0305-0270 .- 1365-2699.
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Amazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types. Location: Amazonia. Taxon: Angiosperms (Magnoliids; Monocots; Eudicots). Methods: Data for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny. Results: In the terra firme and v & aacute;rzea forest types, the phylogenetic composition varies by geographic region, but the igap & oacute; and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R-2 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R-2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types. Main Conclusion: Numerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions.
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| 9. |
- Mehandzhiyski, Alexandar, et al.
(författare)
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Microscopic Insight into the Structure-Processing-Property Relationships of Core-Shell Structured Dialcohol Cellulose Nanoparticles
- 2022
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Ingår i: ACS Applied Bio Materials. - : American Chemical Society (ACS). - 2576-6422. ; 5:10, s. 4793-4802
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Tidskriftsartikel (refereegranskat)abstract
- In the quest to develop sustainable and environmentally friendly materials, cellulose is a promising alternative to synthetic polymers. However, native cellulose, in contrast to many synthetic polymers, cannot be melt-processed with traditional techniques because, upon heating, it degrades before it melts. One way to improve the thermoplasticity of cellulose, in the form of cellulose fibers, is through chemical modification, for example, to dialcohol cellulose fibers. To better understand the importance of molecular interactions during melt processing of such modified fibers, we undertook a molecular dynamics study of dialcohol cellulose nanocrystals with different degrees of modification. We investigated the structure of the nanocrystals as well as their interactions with a neighboring nanocrystal during mechanical shearing, Our simulations showed that the stress, interfacial stiffness, hydrogen-bond network, and cellulose conformations during shearing are highly dependent on the degree of modification, water layers between the crystals, and temperature. The melt processing of dialcohol cellulose with different degrees of modification and/or water content in the samples was investigated experimentally by fiber extrusion with water used as a plasticizer. The melt processing was easier when increasing the degree of modification and/or water content in the samples, which was in agreement with the conclusions derived from the molecular modeling. The measured friction between the two crystals after the modification of native cellulose to dialcohol cellulose, in some cases, halved (compared to native cellulose) and is also reduced with increasing temperature. Our results demonstrate that molecular modeling of modified nanocellulose fibers can provide fundamental information on the structure-property relationships of these materials and thus is valuable for the development of new cellulose-based biomaterials.
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| 10. |
- ter Steege, Hans, et al.
(författare)
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Mapping density, diversity and species-richness of the Amazon tree flora
- 2023
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Ingår i: COMMUNICATIONS BIOLOGY. - 2399-3642. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution. A study mapping the tree species richness in Amazonian forests shows that soil type exerts a strong effect on species richness, probably caused by the areas of these forest types. Cumulative water deficit, tree density and temperature seasonality affect species richness at a regional scale.
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