Classification of papyrus fragments by chemometric analysis of near-infrared spectra.

Papyrus has been used for millennia to record information, for sophisticated works of art as well as mundane notes. The collection, identification, and translation of papyrus fragments therefore opens a gateway into the past. To aid the efforts to access the history recorded in papyri, we investigated the suitability of NIR spectroscopy to perform two tasks: One is to support the authentication of ancient papyri, by differentiation of papyri that were manufactured more recently and subjected to accelerated ageing to resemble the originals.

The impact of the carbohydrate-binding module on how a lytic polysaccharide monooxygenase modifies cellulose fibers.

Background: In recent years, lytic polysaccharide monooxygenases (LPMOs) that oxidatively cleave cellulose have gained increasing attention in cellulose fiber modification. LPMOs are relatively small copper-dependent redox enzymes that occur as single domain proteins but may also contain an appended carbohydrate-binding module (CBM). Previous studies have indicated that the CBM "immobilizes" the LPMO on the substrate and thus leads to more localized oxidation of the fiber surface.

Strategies for multivariate characterization and classification of pulps and papers by near-infrared spectroscopy.

Background: Multivariate calibration by Partial Least Squares (PLS) on near-infrared data has been applied successfully in several industrial sectors, including pulp and paper. The creation of multivariate calibration models relies on a set of well-characterised samples that cover the range of the intended application. However, sample sets that originate from an industrial process often show an uneven distribution of reference values.

Oxidized reducing ends in celluloses: Quantitative profiling relative to molar mass distribution by fluorescence labeling.

Fluorescence labeling with N-(1-naphthyl)ethylenediamine is highly effective for quantifying oxidized reducing end groups (REGs) in cellulosic materials. When combined with size exclusion chromatography in DMAc/LiCl, along with fluorescence / multiple-angle laser light scattering / refractive index detection, a detailed profile of C1-oxidized REGs relative to the molecular weight distribution of the cellulosic material can be obtained. In this work, the derivatization process was extensively optimized, to be carried out heterogeneously in the solvent N-methyl-2-pyrrolidone.

Beyond the Surface: A Methodological Exploration of Enzyme Impact along the Cellulose Fiber Cross-Section.

Despite the wide range of analytical tools available for the characterization of cellulose, the in-depth characterization of inhomogeneous, layered cellulose fiber structures remains a challenge. When treating fibers or spinning man-made fibers, the question always arises as to whether the changes in the fiber structure affect only the surface or the entire fiber. Here, we developed an analysis tool based on the sequential limited dissolution of cellulose fiber layers.

Oxidation of cellulose fibers using LPMOs with varying allomorphic substrate preferences, oxidative regioselectivities, and domain structures.

Lytic polysaccharide monooxygenases (LPMOs) are excellent candidates for enzymatic functionalization of natural polysaccharides, such as cellulose or chitin, and are gaining relevance in the search for renewable biomaterials. Here, we assessed the cellulose fiber modification potential and catalytic performance of eleven cellulose-active fungal AA9-type LPMOs, including C1-, C4-, and C1/C4-oxidizing LPMOs with and without CBM1 carbohydrate-binding modules, on cellulosic substrates with different degrees of crystallinity and polymer chain arrangement, namely, Cellulose I, Cellulose II, and amorphous cellulose. The potential of LPMOs for cellulose fiber modification varied among the LPMOs and depended primarily on operational stability and substrate binding, and, to some extent, also on regioselectivity and domain structure.

Tapping the Full Potential of Infrared Spectroscopy for the Analysis of Technical Lignins.

We present an approach to overcome the challenges associated with the increasing demand of high-throughput characterization of technical lignins, a key resource in emerging bioeconomies. Our approach offers a resort from the lack of direct, simple, and low-cost analytical techniques for lignin characterization by employing multivariate calibration models based on infrared (IR) spectroscopy to predict structural properties of lignins (i. e.

A novel approach to analyze the impact of lytic polysaccharide monooxygenases (LPMOs) on cellulosic fibres.

Enzymatic treatment of cellulosic fibres is a green alternative to classical chemical modification. For many applications, mild procedures for cellulose alteration are sufficient, in which the fibre structure and, therefore, the mechanical performance of cellulosic fibres are preserved. Lytic polysaccharide monooxygenases (LPMOs) bear a great potential to become a green reagent for such targeted cellulose modifications.

Profiling of historical rag papers by their non-cellulosic polysaccharide composition.

Hemicellulose and pectin are noteworthy components of historical European rag papers, and have not been studied in detail so far. Rag papers were made from used textiles, and fiber-based utilities, such as ropes and bags. These had been prepared until the mid-19 century from plant-based fibers.

Study toward a More Reliable Approach to Elucidate the Lignin Structure-Property-Performance Correlation.

The correlation between lignin structure, its properties, and performance is crucial for lignin engineering in high-value products. Currently, a widespread approach is to compare lignins which differ by more than one parameter (i.e.

Towards Tailored Dialdehyde Cellulose Derivatives: A Strategy for Tuning the Glass Transition Temperature.

The derivatization of dialdehyde cellulose (DAC) has received increasing attention in the development of sustainable thermoplastics. In this study, a series of dialcohol celluloses were generated by borohydride reduction, which exhibited glass transition temperature (T ) values ranging from 23 to 109 °C, depending on the initial degree of oxidation (DO) of the DAC intermediate. However, the DAC derivatives did not exhibit thermoplastic behavior when the DO of the modified DAC was below 26 %.

Lignin-Based Polyurethanes from the Blocked Isocyanate Approach: Synthesis and Characterization.

Lignin, the world's second most abundant biopolymer, has been investigated as a precursor of polyurethanes due to its high availability and large amount of hydroxyls present in its structure. Lignin-based polyurethanes (LPUs) are usually synthesized from the reaction between lignin, previously modified or not, and diisocyanates. In the present work, LPUs were prepared, for the first time, using the blocked isocyanate approach.

From liquid to solid-state, solvent-free oxidative ammonolysis of lignins - an easy, alternative approach to generate "N-lignins".

A new chemical modification protocol to generate N-lignins is presented, based on Indulin AT and Mg-lignosulfonate. The already known ammonoxidation reaction in liquid phase was used as a starting point and stepwise optimised towards a full solid-state approach. The "classical" liquid ammonoxidation products, the transition products from the optimization trials, as well as the "solid-state" products were comprehensively analysed and compared to the literature.

Debugging periodate oxidation of cellulose: Why following the common protocol of quenching excess periodate with glycol is a bad idea.

Periodate oxidation of cellulose to produce "dialdehyde cellulose" (DAC) has lately received increasing attention in sustainable materials development. Despite the longstanding research interest and numerous reported studies, there is still an enormous variation in the proposed preparation and work-up protocols. This apparently reduces comparability and causes reproducibility problems in DAC research.

Chemical composition of the lipophilic compounds from the rind and pith of papyrus ( L.) stems.

Papyrus ( L.) is a sedge plant with a high rate of biomass productivity that represents an interesting raw material to produce chemicals, materials and fuels, which are currently still obtained from fossil resources, in the context of a lignocellulosic biorefinery. In this work, the content and chemical composition of the lipids present in papyrus stems were thoroughly studied.

Reductive Amination of Dialdehyde Cellulose: Access to Renewable Thermoplastics.

The reductive amination of dialdehyde cellulose (DAC) with 2-picoline borane was investigated for its applicability in the generation of bioderived thermoplastics. Five primary amines, both aliphatic and aromatic, were introduced to the cellulose backbone. The influences of the side chains on the course of the reaction were examined by various analytical techniques with microcrystalline cellulose as a model compound.

Exploring Alkyl-O-Alkyl Ether Structures in Softwood Milled Wood Lignins.

Recent studies have suggested that there are significant amounts of various alkyl ether (Alk-O-Alk; Alk = alkyl) moieties in a spruce native lignin preparation, milled wood lignin (SMWL). However, the comprehensive NMR assignment to these moieties has not been addressed yet. This study focused on investigating different types of Alk-O-Alk structures at the α- and γ-positions of the lignin side chain in an heteronuclear single-quantum coherence (HSQC) spectrum of SMWL using experimental NMR data of lignin and synthesized model compounds.

Sustainable polyesters via direct functionalization of lignocellulosic sugars.

The development of sustainable plastics from abundant renewable feedstocks has been limited by the complexity and efficiency of their production, as well as their lack of competitive material properties. Here we demonstrate the direct transformation of the hemicellulosic fraction of non-edible biomass into a tricyclic diester plastic precursor at 83% yield (95% from commercial xylose) during integrated plant fractionation with glyoxylic acid. Melt polycondensation of the resulting diester with a range of aliphatic diols led to amorphous polyesters (M = 30-60 kDa) with high glass transition temperatures (72-100 °C), tough mechanical properties (ultimate tensile strengths of 63-77 MPa, tensile moduli of 2,000-2,500 MPa and elongations at break of 50-80%) and strong gas barriers (oxygen transmission rates (100 µm) of 11-24 cc m day bar and water vapour transmission rates (100 µm) of 25-36 g m day) that could be processed by injection moulding, thermoforming, twin-screw extrusion and three-dimensional printing.

Acetylation of cellulose - Another pathway of natural cellulose aging during library storage of books and papers.

Gaseous acetic acid is formed under conditions of storage of historic paper objects. Its presence not only promotes hydrolytic cleavage of cellulose, but also causes acetylation of the cellulosic material to very small degree. The acetylation reaction proceeds under ambient conditions and without catalyst.

Facile Preparation of Mechanically Robust and Functional Silica/Cellulose Nanofiber Gels Reinforced with Soluble Polysaccharides.

Nanoporous silica gels feature extremely large specific surface areas and high porosities and are ideal candidates for adsorption-related processes, although they are commonly rather fragile. To overcome this obstacle, we developed a novel, completely solvent-free process to prepare mechanically robust CNF-reinforced silica nanocomposites via the incorporation of methylcellulose and starch. Significantly, the addition of starch was very promising and substantially increased the compressive strength while preserving the specific surface area of the gels.

High-Resolution Profiling of the Functional Heterogeneity of Technical Lignins.

In technical lignins, functionality is strongly related to molar mass. Hence, any technical lignin exhibits concurrent functionality-type distribution (FTD) along its molar mass distribution (MMD). This study combined preparative size-exclusion chromatography with offline characterizations to acquire highly resolved profiles of the functional heterogeneity of technical lignins, which represent crucial information for their material use.

Assessing Fire-Damage in Historical Papers and Alleviating Damage with Soft Cellulose Nanofibers.

The conservation of historical paper objects with high cultural value is an important societal task. Papers that have been severely damaged by fire, heat, and extinguishing water, are a particularly challenging case, because of the complexity and severity of damage patterns. In-depth analysis of fire-damaged papers, by means of examples from the catastrophic fire in a 17th-century German library, shows the changes, which proceeded from the margin to the center, to go beyond surface charring and formation of hydrophobic carbon-rich layers.

Fourier transform and near infrared dataset of dialdehyde celluloses used to determine the degree of oxidation with chemometric analysis.

This dataset is related to the research article entitled ``A fast method to measure the degree of oxidation of dialdehyde celluloses using multivariate calibration and infrared spectroscopy''. In this article, 74 dialdehyde cellulose samples with different degrees of oxidation were prepared by periodate oxidation and analysed by Fourier-transform infrared (FTIR) and near-infrared spectroscopy (NIR). The corresponding degrees of oxidation were determined indirectly by periodate consumption using UV spectroscopy at 222 nm and by the quantitative reaction with hydroxylamine hydrochloride followed by potentiometric titration.

A fast method to measure the degree of oxidation of dialdehyde celluloses using multivariate calibration and infrared spectroscopy.

The properties of dialdehyde celluloses, which are usually generated by periodate oxidation, are highly dependent on the aldehyde content, i.e. the degree of oxidation (DO).