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Showing 1 to 20 of 37 for “"Lignins"”.
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Comprehensive Structural and Thermal Characterization of Selected Grass Lignins
… region is richer in PCGL. Among the selected lignins, PCGL and SGL have higher degrees of condensation compared to BBSL and MSL. Although, the selected grass lignins primarily constitute similar structural moieties and inter-unit linkages, they widely wary in the amount present. In summary, …
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Studies of Sustainable Polymers: Novel Lignins to Reprocessable Polymers
… For the degradation process of the resultant lignins, the presence of more C-monolignol during polymerization facilitated greater degradation. This work demonstrated the chemical factors that influenced the physical properties of lignin and lignin degradation, which could impact biofuel …
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Dilute solution studies of molecular weight distributions of nitrocellulose, modified lignins and PMMA graft polymers
… the hydrodynamic behavior of hydroxypropylated lignins using GPC/LALLS/DV and VPO. These materials were found to increase in molecular weight upon storage in solution due to association. Special precautions had to be taken in running experiments to obtain the correct molecular weights and …
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Structural changes to Pinus radiata wood lignin during kraft pulping and bleaching
… native (within wood) and residual (within pulps) lignins. A better understanding of the structure of lignin will assist the development of improved pulping and bleaching sequences. However, before this can be done, it is necessary to develop approaches to lignin isolation which provide more …
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Analysis of polymeric extractives of Western Juniper (Juniperus occidentalis) heartwood
… is comparable to similar correlations found in lignins. The two other long-range correlations at around δ = 5.00 ppm and δ = 5.30 ppm are not assignable to any lignin-like structure. The 2D HMBC experiment can be used as an improved quantitative NMR technique for the assessment of labelled …
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Synthetic, Sulfated, Lignin-Based Anticoagulants
… which is more homogenous compared to previous lignins with respect to its inter-monomeric linkage. SbO4L is a selective inhibitor of thrombin and plasmin. SbO4L was found to act via a unique mechanism targeting thrombin exosite 2 in a manner similar to platelet glycoprotein Ibα (GPIbα). …
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Lignin acrylate derivatives and their behaviors in free radical copolymerizations
… were taken as model compounds for lignins and hydroxypropyl lignins to study their vinylation and copolymerization behaviors. Lignin model compounds and lignin were subjected to reaction with isocyanatoethyl methacrylate (IEM) using dibutyltin dilaurate as catalyst. The acrylate …
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Valorising South African lignin as a sustainable bitumen additive in pavement engineering
… mills around South Africa. The kraft and soda lignins were separated from their respective spent liquors using acid precipitation, while the lignosulfonate spent liquor was spray dried. The lignins were characterised, and they were then blended with bitumen at a 10 wt% blending ratio. This …
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Biochemical Evaluation of Lignin-like Molecules
… (HSV-1). Based on previous findings on sulfated lignins a size-dependent study on unsulfated LMWLs was done. The unsulfated lignins were found to not only inhibit HSV-1 entry into mammalian cells, but were more potent than sulfated lignins. Interestingly, shorter chains were found to be as active …
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Kraft lignin as a fuel for the rotary lime kiln
… in experiments using three different kraft lignins at various levels of replacement for natural gas. Lignins precipitated from black liquor by both the mineral acid and the carbon dioxide process were burned successfully as the sole fuel, or in conjunction with natural gas, to yield a stable …
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Understanding the Relative Importance of the Effects of Soluble and Insoluble Inhibitors on the Enzyme Digestibility of Steam Pretreated Radiata Pine
… present in this cocktail. Inhibition by lignin: Lignins were isolated from three insoluble substrates of differing pretreatment severity and their inhibitory effects on the digestibility of bleached kraft pulp were determined. Results showed: (i) that the inhibitory effects of added lignins …
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Functional analysis of soybean dirigent genes
… lignans, such as (+) or (-)-pinoresinol, and lignins, from the selective coupling of specific stereoisomers of deprotonated alcohol molecules. Lignans and lignins have been shown to have antimicrobial properties and human health benefits when polymerized. The expression patterns in leaves of …
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Lignin valorization
… of the structural features of such isolated lignins was performed through the use of a wide range of analytical methods. Alkaline lignins resulted in a better candidate as carbon precursor and macromonomers for the synthesis of polymer than organosolv lignin. In fact, alkaline lignins showed …
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Multiple ecosystem services in smallholder agriculture
… biomass and functional traits (green tissue N, lignins, polyphenols, lignins+polyphenols) of fallow plants and the condition of soils were quantified. Positive associations of tissue content of lignins+polyphenols with soil organic carbon (SOC) and steady infiltration rates indicated a role of …
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Hydroxypropylation of lignin and lignin-like model compounds
… of the particular lignin preparation. Various lignins including Kraft lignin, methylated Kraft lignin, and demethylated Kraft lignin were employed to reacted with propylene oxide at 190°c. The effect of lignin structure variations on both reaction rate and molar substitution were determined. …
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THE NATURE OF BOND FORMATION AND FAILURE IN WOOD-ADHESIVE SYSTEMS
… the adhesives interact chemically with mainly lignins and extractives and to a lesser extent with cellulose. These interactions are thought to be covalent links as only this type of bond will account for the spectral changes noted. The dopant compounds used were urea, dimetol urea, methylene …
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Mass Spectrometric Studies on Lignin Sequencing and Fast Pyrolysis, Functional-Group Selective Ion-Molecule Reactions and Reactivity of Bi- and Triradicals
… for the structural elucidation of unnknown lignins. Gas phase ion-molecule reaction can be useful in study of reaction kinetics and mechanism and even in probing the functional groups in unknown molecules. The functional group selective ion-molecule reaction has great potential for unknown …
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Microbial transformation of lignin
… decreased continually. Analyses of degraded lignins divulged that A. fumigatus brought about corporeal changes in the lignin macromolecule whereas C. versicolor was responsible for only cursory changes. Data obtained from degraded lignins such as OCH₃ loss, OH loss and yield of monomers and …
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Beiträge zur Entwicklung Wasser speichernder Materialien auf Basis von Stärke und Lignin
… was auf oxidativ bedingte Strukturänderungen des Lignins zurückzuführen war. Diese bestanden im Wesentlichen in der Spaltung und Oxidation der Lignin-Seitenkette sowie der Hydroxylierung der Seitenkette und aromatischer Strukturen. Die Vernetzung von Lignin mit Poly-(ethylenglycol)-diglycidylether …
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Functional properties of polyurethane based sealants blended with polymeric modifiers
… incorporating various types of kraft processed lignins including softwood, hardwood, and eucalyptus wood lignin, were produced and their performance properties established in a research program which sought to develop more durable cost effective sealants as well as cultivate a market for lignin, …
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