| 1. |
- van Tour, Peter, 1966-
(författare)
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Counterpoint and Partimento : Methods of Teaching Composition in Late Eighteenth-Century Naples
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During the second half of the eighteenth century, the city of Naples had three music conservatories: the Conservatorio di Santa Maria di Onofrio, the Conservatorio di Santa Maria di Loreto, and the Conservatorio di Santa Maria della Pietà de’ Turchini. Through disciplines such as solfeggio, partimento, and counterpoint, the students at these institutions received highly professional training in singing, instrumental playing, and composition.This study reveals new evidence that partimenti were used not only as exercises in keyboard playing, but also as exercises in written counterpoint. As counterpoint exercises, partimenti were used either as bass lines over which students wrote one or several contrapuntal parts, or as notational devices that facilitated the sketching of fugues.Musicologists have previously encountered considerable difficulties in identifying and describing differences between the schools of Leonardo Leo and Francesco Durante, represented by the terms Leisti and Durantisti. This study shows that these schools are primarily defined through different methods of teaching counterpoint. Contemporary counterpoint notebooks show that the maestri at Sant’Onofrio and Santa Maria di Loreto followed Durante’s teaching methods, while the maestri at La Pietà followed Leo’s teaching methods. The school of Durante emphasized the writing of melodic lines over a hexachordal scale or a partimento bass, using different methods, such as the moti del basso and prescribed conditions. The school of Leo favored the use of invertible counterpoint, emphasizing skills in sketching and writing choral fugues from subjects and countersubjects.For the first time, the partimento and solfeggio repertoire used at the Neapolitan conservatories has been systematically investigated through the creation of two research tools, the databases UUPart: The Uppsala Partimento Database and UUSolf: The Uppsala Solfeggio Database, published online on two companion websites.
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| 2. |
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| 3. |
- Bjurhager, Ingela
(författare)
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Mechanical behaviour of hardwoods : effects from cellular and cell wall structures
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med den här avhandlingen var att undersöka mekaniska egenskaper hos olika arter av lövträd, och koppla egenskaperna till cell- och cellväggsstrukturen i materialet. Arterna som omfattades av undersökningen var Europeisk asp (Populus tremula), hybridasp (Populus tremula x Populus tremuloides) och ek (Quercus robur). Arterna inom familjen Populus, inklusive den snabbväxande hybridaspen, har på senare tid kommit att användas inom ett stort antal projekt inom genforskningen. Det har i sin tur ökat behovet av noggrannare bestämning av mekaniska egenskaper hos dessa arter. Ek har sedan tusentals år tillbaka varit ett populärt konstruktionsmaterial; något som har resulterat i ett stort antal arkeologiska ekfynd. Konservering av dessa inkluderar ofta dimensionsstabilisering med hjälp av polyetylen-glykol (PEG); en kemikalie som man vet påverkar de mekaniska egenskaperna. I vilken utstäckning detta sker är däremot inte helt klarlagt. Studien på euoropeisk asp och hybridasp inkluderade utveckling av en ny metod för provning av små juvenila prov i grönt tillstånd. Töjningsmätningar gjordes med hjälp av digital speckelfotografering (DSP). Axiell dragstyvhet och draghållfasthet var av speciellt intresse. Sämre mekaniska egenskaper hos hybridaspen korrelerade med medelvärden på densitet, som var lägre för hybriden än för den Europeiska aspen. Ek undersöktes i svällt tillstånd, där svällningen inducerades med hjälp av PEG (molekylvikt 600). Axiell dragstyvhet och draghållfasthet samt radiell tryckstyvhet och ytspänning undersöktes. Töjningsmätningar i axiell riktning gjordes med hjälp av videoextensiometer, medan töjning i radiell riktning gjordes med hjälp av DSP. Övrig karakterisering av materialet inkluderade scanning electron microscopy (SEM), röntgenmikrotomografi och wide angle X-ray scattering (WAXS) för bestämning av mikrofibrillvinkel. Axiell dragstyvhet och draghållfasthet påverkades bara marginellt av PEG-behandlingen. WAXS-mätningarna visade att mikrofibrillvinkeln i materialet var mycket liten. Därigenom blir de mekaniska egenskaperna i axiell riktning till stor del beroende av mikrofibrillerna, vilket samtidigt minimerar den mjukningseffekt som PEG-impregneringen har på cellväggsmatrisen. De mekaniska egenskaperna i radiell kompression påverkades däremot starkt negativt av impregneringen. Detta antogs bero på den försvagande och uppmjukande effekt som PEG:en har på de radiellt orienterade märgstrålarna i veden.
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| 4. |
- Brodin, Thomas, 1963-
(författare)
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Ovarian Reserve and Assisted Reproduction
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Treatment success in IVF-ICSI is mainly limited by female age, but differences in ovarian reserve (OR; the remaining pool of oocytes and their quality) between individuals modify treatment prerequisites among women of similar age. OR may be assessed by OR tests (ORTs). The main aims of this work were to study menstrual cycle length (MCL), basal levels of circulating gonadotrophins, antral follicle count (AFC) and serum Anti-Müllerian hormone (AMH) levels and their associations with and prognostic capacities regarding IVF-ICSI outcome in large cohorts of unselected women.Age-adjusted MCL was positively and linearly associated with pregnancy rates (PRs), live-birth rates (LBRs) and ovarian response to controlled ovarian hyperstimulation. An MCL of >34 days almost doubled the LBR compared with an MCL of <26 days.The grouped variable ‘combined FSH and LH levels’ was superior to both individual gonadotrophin levels and the LH:FSH ratio. The highest mean PR was seen in connection with a combination of FSH <6.7 U/l with LH >4.9 U/l; PRs were lowest when FSH-LH levels were opposite to this (high-low) and intermediate when FSH-LH levels were low-low or high-high. Associations with LBR and ovarian response were similar as those for PR.AFCs and serum AMH levels were positively and log-linearly associated with PR, LBR and ovarian response. Success rates levelled out above AFC 30 or AMH 5 ng/ml. Treatment outcome was superior among women with polycystic ovaries.Among the studied ORTs, logAFC and logAMH concentration correlated most strongly. After multivariate testing, entering all studied ORTs, AMH and female age remained independently associated with LBR. AMH + AFC + age predicted both poor and excessive ovarian responses with high accuracy.Adjusting for age and oocyte yield, all ORTs remained significant for LBR, implying that ORTs also capture information on oocyte quality.In conclusion, measures of OR are strongly associated with PR, LBR and ovarian response in a log-linear fashion, and partly reflect oocyte quality. The OR spectrum is continuous, from small ‘oligofollicular’ ovaries (the low extreme) to polycystic ovaries (the high extreme). Among the studied ORTs, AMH together with age provide the most powerful basal estimate for IVF/ICSI outcome.
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| 5. |
- Djahedi, Cyrus, 1985-
(författare)
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Deformation of cellulose allomorphs studied by molecular dynamics
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cellulose-based materials draw their good mechanical properties from the cellu-lose crystal. Improved understanding of crystal properties could lead to a wider range of applications for cellulose-based materials, Cellulose crystals show high axial Youngs modulus. Cellulose can attain several allomorphic forms which show unique structural arrangements in terms of both intra-molecular and inter-molecular bonding, as well as unit cell parameters and chain packing. Although several studies have confirmed that mechanical tensile properties of cellulose differ between different allomorphic forms, few reports have investigated the deformation mechanisms explaining the differences.In the first part of this thesis, the tensile elastic Youngs modulus of cellulose allo-morphs Iβ, II and III I were calculated under uniform conditions using Molecular Dynamics simulation techniques. As expected, a difference in modulus valuesc ould be observed, and the cooperative nature of energy contributions to crys-tal modulus is apparent. The allomorphs also show large differences in terms of how contributions to elastic energy are distributed between covalent bonds,angles, dihedrals, electrostatic forces, dispersion and steric forces.In the second part of this thesis, the cellulose Iβ and II allomorphs were sub-jected to a more detailed structural study. The purpose was to clarify how the deformation of the central glucosidic linkage between the monomer units depends on the hydrogen-bonding structures. This was carried out by studying simulated vibrational spectra and local deformations in the crystals.The results presented in this thesis confirm the differences in the tensile elastic properties of these cellulose allomorphs. These differences can in part be explained by the different intra-molecular hydrogen bonding patterns between allomorphs. Deformation mechanisms are discussed. The results are in supportof the so called ”leverage effect” proposed in the literature. The present analysis shows significant differences in details of deformation mechanisms compared with previous simpler analyses.
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| 6. |
- Garemark, Jonas
(författare)
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Integrated Cellulosic Wood Aerogel Structures
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Highly porous aerogels based on renewable materials that possess structural functionality are appealing for sustainable energy regulation and harvesting. Achieving structural anisotropy provides advantageous directional diffusion and mechanical strength, however, introduces great engineering challenges, such as complex, costly, and time-consuming processing. Direct use of wood, where nanocellulose is favorably orientated, offers the opportunity of forming low-cost, scalable, and eco-friendly aerogels.This thesis explores a new type of nanostructured wood material design by filling the empty wood space with cellulosic aerogel structures based on its intrinsic biopolymers. The structure control is achieved through selective reassembly of the cell wall nanocomponents by cell wall partial dissolution and regeneration. The resultant structures, named integrated wood aerogels, show a unique combination of high specific surface area and strength due to partial retention of the wood hierarchical structure and formation of mesoporous nanofibrillated networks occupying the lumen. Different chemical systems are investigated, including DMAc/LiCl, ionic liquid (IL), and aqueous NaOH, and the processing-structure-property relationships are investigated. DMAc/LiCl is successfully used as proof of concept for integrated wood aerogel formation, but moisture sensitivity and toxicity of the system hinder further development. The IL [MTBD][MMP] is developed to solve the issues and to improve the structure control in cell wall dissolution and regeneration. An aqueous NaOH system advances the integrated cellulosic wood aerogel preparation further, considering low cost and greener chemistry. Wood composition, lignin in particular, is critical to the processing and final properties of the integrated wood aerogel. The influence of lignin content is investigated based on IL and NaOH systems. The influence of processing (such as chemical system, time and temperature) on the structure and properties (e.g. porosity, specific surface area, mechanical performance, thermal conductivity and charge density) of the aerogels are studied. Ascribing to the structure-property profile, the application of the integrated aerogel for efficient thermal insulation is demonstrated. Inspired by the water uptake in plants, high-performing pH-responsive wood power generators are formed based on water evaporation-induced electricity. The integrated aerogel structure greatly increases the solid/liquid interphase while allowing excellent mass diffusion.The methodologies presented in this thesis for selective nanoscale reassembly of the wood cell wall pave the way for advanced wood nanostructure control. The integrated wood aerogel structure reported here provides a universal material platform for advanced material design, such as a self-sustaining wood power generator. The facile and scalable processing contribute toward sustainable high-performing bioaerogels which can compete with fossil-based materials.
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| 7. |
- Hu, Yanlei, et al.
(författare)
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Composites of Silk Nanofibrils and Metal-Organic Framework Nanosheets for Fluorescence-Based Sensing and UV Shielding
- 2023
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Ingår i: ACS Applied Nano Materials. - : American Chemical Society. - 2574-0970. ; 6:7, s. 6046-6055
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Tidskriftsartikel (refereegranskat)abstract
- Silk fibroin, a widely used natural biopolymer, presents remarkable flexibility and biodegradability, making it of great interest as a polymer matrix for functional composite materials. Herein, composites of silk nanofibrils and metal-organic framework (MOF) nanosheets were successfully fabricated by a coincubation and coassembly process. Under heat incubation, silk fibroin self-assembled into one-dimensional nanofibrils, while MOF nanosheets simultaneously covered or wrapped on the silk nanofibrils in a water suspension. Transparent composite membranes were obtained from their water suspensions by the solution casting method. The regenerated silk nanofibrils formed a network structure, and the integrated MOF nanosheets (0.1 to 3.0 wt %) endowed the composites with aggregation-induced emission luminogen (AIEgen)-based fluorescence. The fluorescence intensity of the composites was significantly enhanced owing to the interfacial interactions between silk nanofibrils and MOF nanosheets. The composite membranes also offer excellent UV shielding while maintaining optical transparency in the visible spectrum. This work provides an efficient pathway to fabricate luminescent silk protein-based composites for functional materials such as fluorescence sensing and anticounterfeiting.
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| 8. |
- Koskela, Salla, et al.
(författare)
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An Oxidative Enzyme Boosting Mechanical and Optical Performance of Densified Wood Films
- 2023
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 19:17
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Tidskriftsartikel (refereegranskat)abstract
- Nature has evolved elegant ways to alter the wood cell wall structure through carbohydrate-active enzymes, offering environmentally friendly solutions to tailor the microstructure of wood for high-performance materials. In this work, the cell wall structure of delignified wood is modified under mild reaction conditions using an oxidative enzyme, lytic polysaccharide monooxygenase (LPMO). LPMO oxidation results in nanofibrillation of cellulose microfibril bundles inside the wood cell wall, allowing densification of delignified wood under ambient conditions and low pressure into transparent anisotropic films. The enzymatic nanofibrillation facilitates microfibril fusion and enhances the adhesion between the adjacent wood fiber cells during densification process, thereby significantly improving the mechanical performance of the films in both longitudinal and transverse directions. These results improve the understanding of LPMO-induced microstructural changes in wood and offer an environmentally friendly alternative for harsh chemical treatments and energy-intensive densification processes thus representing a significant advance in sustainable production of high-performance wood-derived materials.
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| 9. |
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| 10. |
- Medina, Lilian
(författare)
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High Clay Content Cellulose Nanocomposites for Mechanical Performance and Fire Retardancy
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Materials based on wood can offer sustainable alternatives to fossil-based plastics and composites, and show interesting mechanical properties. However, the issue of their flammability is generally unresolved. In this thesis, eco-friendly, fire retardant clay-cellulose nanofibril materials are investigated. The work focuses particularly on structure-property relationships and physical properties of these materials. The thesis is structured in two parts. The first part is concerned with paper-like materials, designated as “films”. The second part discusses materials of high-porosity, so-called “foams”.In the first part, films of clay and cellulose nanofibrils are prepared by filtration from water. The composition is systematically varied (from 0 to 100% clay) and effects on the nanostructure are investigated by synchrotron X-ray scattering, helium pycnometry and microscopy techniques. The mechanical properties of the films are determined by tensile testing, optical properties are measured by transmittance/haze tests, and strong effects of nanostructure are observed. A film with 50 wt% clay is demonstrated as a fire retardant coating on wood, by cone calorimetry testing. These films are also pre-impregnated with epoxy precursors and cured, to form ternary composites of clay, cellulose nanofibrils, and epoxy. These ternary nanocomposites show remarkably well-preserved mechanical and gas barrier properties in moist environment.In the second part, foams of high porosity are prepared by freeze-drying a suspension based on poly(vinyl alcohol), cellulose nanofibrils, and clay. The cellular structure is investigated by scanning electron microscopy, and effects from composition and cross-linking are analyzed. The compressive properties of the foams are determined and related to their structure. Addition of poly(vinyl alcohol) influences the unique degradation and charring behavior of cellulose nanofibrils in the presence of clay so that fire retardancy is decreased.
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| 11. |
- Mishchenko, Kateryna, 1973-
(författare)
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Numerical Algorithms for Optimization Problems in Genetical Analysis
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The focus of this thesis is on numerical algorithms for efficient solution of QTL analysis problem in genetics.Firstly, we consider QTL mapping problems where a standard least-squares model is used for computing the model fit. We develop optimization methods for the local problems in a hybrid global-local optimization scheme for determining the optimal set of QTL locations. Here, the local problems have constant bound constraints and may be non-convex and/or flat in one or more directions. We propose an enhanced quasi-Newton method and also implement several schemes for constrained optimization. The algorithms are adopted to the QTL optimization problems. We show that it is possible to use the new schemes to solve problems with up to 6 QTLs efficiently and accurately, and that the work is reduced with up to two orders magnitude compared to using only global optimization.Secondly, we study numerical methods for QTL mapping where variance component estimation and a REML model is used. This results in a non-linear optimization problem for computing the model fit in each set of QTL locations. Here, we compare different optimization schemes and adopt them for the specifics of the problem. The results show that our version of the active set method is efficient and robust, which is not the case for methods used earlier. We also study the matrix operations performed inside the optimization loop, and develop more efficient algorithms for the REML computations. We develop a scheme for reducing the number of objective function evaluations, and we accelerate the computations of the derivatives of the log-likelihood by introducing an efficient scheme for computing the inverse of the variance-covariance matrix and other components of the derivatives of the log-likelihood.
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| 12. |
- Oliaei, Erfan, 1991-
(författare)
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Lignocellulose Biocomposites– A Comparison of Wood Fibers and Microfibrillated Lignocellulose
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- All-lignocellulose composites, meaning densified fiber or fibril materials without added binder, show interesting mechanical properties and can be eco-friendly. Composites based on hot-pressed microfibrillated lignocellulose (MFLC) and lignocellulosic wood fiber (WF) reinforcements are compared with respect to processing, structure, mechanical properties, and eco-indicators. Also, these reinforcements are compared in hot-pressed degradable lignocellulosic crosslinked polycaprolactone (c-PCL) biocomposites based on in-situ polymerization of new caprolactone oligomers.The intermediate lignin content (≈11%) was favorable for MFLC preparation, although the cumulative energy demand was high for mechanical disintegration from unbleached softwood kraft pulp. The mechanical properties were much better for random-in-plane MFLC compared with WF composites due to lower porosity, better interfiber bonding, and smaller-scale defects. Data for strain-field development during tensile tests was in support of these findings. For c-PCL biocomposites, much higher ultimate strength was obtained for the c-PCL/MFLC composites compared with c-PCL/WF. The most important reason was the strainhardening behavior combined with higher strain to failure, since the scale of developing defects was much smaller with MFLC reinforcement.
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| 13. |
- Prakobna, Kasinee, 1983-
(författare)
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Biocomposites Based on Core-Shell Cellulose Nanofibers : Preparation, Structure, and Properties
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cellulose nanofibers (CNFs) are of interest as load-bearing components for polymer matrix nanocomposites. A wide range of nanostructured materials including nanopaper/films, foams, aerogels, and hydrogels can be prepared from CNFs. The material performance can be fine-tuned when CNFs are combined with different polymer matrices. The main idea of the present study is to test the hypothesis that the concept of Core-shell CNFs can provide processing and performance advantages for nanocomposites through improved nanostructural control.The problems of matrix distribution and interface structure at nanoscale are investigated. The first part of this thesis (Paper I-III) describes an alternative preparation procedure for biocomposites based on the Core-shell concept. Inspired by the structural framework and mechanical function of the primary cell wall in plants, Core-shell CNFs are formed by coating wood CNFs with a polysaccharide matrix, and are subsequently used for fabrication of biocomposite films. The nanostructure of Core-shell CNFs and their nanocomposites is characterized. Mechanical properties of the biocomposites at various hydration conditions are investigated. A study on molecular water mobility and moisture stability of the materials is conducted. In the present thesis, three different biological polysaccharides including amylopectin, xyloglucan and galactoglucomannan have been used for man-made nanocomposites based on Core-shell nanofibers.The later sections of the thesis (Paper IV-V) describe an alternative method to disintegrate holocellulose nanofibers from wood chips. These CNFs based on holocellulose possess Core-shell structure with native hemicelluloses as “shell”. Peracetic acid pretreatment is used for the preparation of holocellulose. This procedure is a promising single-step pulping as preparation for nanofibrillation. The nanostructure of the holocellulose nanofibers are characterized, and compared with CNFs prepared from enzymatic pretreatment. The holocellulose nanofibers are used for preparation of films and porous materials. The influence of nanostructural characteristics of two different nanofibers (CNFs from enzymatic pretreatment vs holocellulose nanofibers from peracetic acid pretreatment) on final properties of the nanocomposites is clarified. Favorable characteristics of Core-shell fibrils are reported in terms of colloidal stability, controlled matrix distribution, improved interface characteristics, and improved hygromechanical properties of the biocomposites. In both a scientific and industrial context, the Core-shell nanofiber concept thus offers great potential for the materials design of new cellulose nanomaterials with unique characteristics.
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| 14. |
- Schildt, Maria, 1966-
(författare)
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Gustav Düben at Work : Musical Repertory and Practice of Swedish Court Musicians, 1663-1690
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation is concerned with musical transfer in seventeenth-century northern Europe, and in particular the repertory and the musical practice of the musicians of the Swedish royal court during the period of the tenure of Gustav Düben as court chapel master (1663–1690). The starting point of and the precondition for the study is provided by the extensive musical collection, the Düben Collection, held by Uppsala University library: the remnants of the music library of the Düben family of whom four were Swedish court chapel masters. The collection has not previously been considered systematically in its entirety and the present study has answered many questions in areas such as establishing the function of the music as the repertory of the court musicians, the connection with the German Church in Stockholm and the identification of many of the anonymous sources and of concordances outside the collection. The extant music has been identified as belonging to specific areas of repertory, for example music for weddings, funerals and secular courtly divertissements. The study considers the different aspects of response to cultural transfer, above all the processes of the adaption of the music to the local context, and two forms of adaptation are specifically considered, the alteration of the texts and the modification of the scoring. Finally, the extant music composed by Gustav Düben has been narrowed down and is discussed with a special focus on borrowing and the practice of imitatio.
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| 15. |
- Wang, Shennan, Dr. 1992-, et al.
(författare)
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Strong, transparent, and thermochromic composite hydrogel from wood derived highly mesoporous cellulose network and PNIPAM
- 2022
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Ingår i: Composites. Part A, Applied science and manufacturing. - : Elsevier BV. - 1359-835X .- 1878-5840. ; 154, s. 106757-
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Tidskriftsartikel (refereegranskat)abstract
- Composite polymer hydrogels are of significant interests for high optical transparency and mechanical performance. In this work, a strong and transparent composite hydrogel is developed from a highly mesoporous cellulose network prepared from wood via top-down delignification followed by TEMPO-mediated oxidation and in situ polymerization of PNIPAM. Individualization of cellulose microfibrils inside the wood cell wall is critical for the fabrication of free-standing composite hydrogel with high water content of 94.9 wt% and high optical transmittance of 85.8% with anisotropic light scattering behavior. The composite hydrogel also showed anisotropic mechanical properties with a tensile strength, Young's modulus and toughness of 317 kPa, 5.4 MPa, and 39.2 kJ m- 3 in axial direction, and 152 kPa, 0.31 MPa and 57.1 kJ m- 3 in the transverse direction, respectively. It also showed thermochromic behavior, i.e., reversibly changing between transparent and brightly white by a temperature change between 25 and 40 degrees C, demonstrating great potential for optical applications.
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| 16. |
- Wang, Shennan, Dr. 1992-, et al.
(författare)
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Wood xerogel for fabrication of high-performance transparent wood
- 2023
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Optically transparent wood has been fabricated by structure-retaining delignification of wood and subsequent infiltration of thermo- or photocurable polymer resins but still limited by the intrinsic low mesopore volume of the delignified wood. Here we report a facile approach to fabricate strong transparent wood composites using the wood xerogel which allows solvent-free infiltration of resin monomers into the wood cell wall under ambient conditions. The wood xerogel with high specific surface area (260 m2 g–1) and high mesopore volume (0.37 cm3 g–1) is prepared by evaporative drying of delignified wood comprising fibrillated cell walls at ambient pressure. The mesoporous wood xerogel is compressible in the transverse direction and provides precise control of the microstructure, wood volume fraction, and mechanical properties for the transparent wood composites without compromising the optical transmittance. Transparent wood composites of large size and high wood volume fraction (50%) are successfully prepared, demonstrating potential scalability of the method.
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| 17. |
- Zha, Li, et al.
(författare)
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Mixed-linkage (1,3;1,4)-beta-D-glucans as rehydration media for improved redispersion of dried cellulose nanofibrils
- 2023
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 300
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Tidskriftsartikel (refereegranskat)abstract
- Improving the redispersion and recycling of dried cellulose nanofibrils (CNFs) without compromising their nanoscopic dimensions and inherent mechanical properties are essential for their large-scale applications. Herein, mixed-linkage (1,3;1,4)-beta-D-glucan (MLG) was studied as a rehydration medium for the redispersion and recycling of dried CNFs, benefiting from the intrinsic affinity of MLG to both cellulose and water molecules as inspired from plant cell wall. MLG from barley with a lower molar ratio of cellotriosyl to cellotetraosyl units was found homogeneously coated on CNFs, facilitating rehydration of the network of individualized CNFs. The addition of barley MLG did not impair the mechanical properties of the CNF/MLG composites as compared to neat CNFs nanopaper. With the addition of 10 wt% barley MLG, dry CNF/MLG composite film was successfully redispersed in water and recycled with well-maintained mechanical properties, while lichenan from Icelandic moss, cationic starch, and xyloglucan could not help the redispersion of dried CNFs.
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