نتایج جستجو برای: milled wood lignin
تعداد نتایج: 51981 فیلتر نتایج به سال:
Given that terahertz (THz) radiation responds to intermolecular forces such as hydrogen bonds, THz time-domain spectroscopy (THz-TDS) has expanded possibilities in cellulose research. In this study, THz-TDS was used investigate the crystallinity of three types cellulose-based materials. Microcrystalline (MCC) and wood were ball milled at different times, pseudo-wood a mixture MCC lignin mass fr...
The composite structure of the S2 layer in the wood cell wall is defined by the angle of the cellulose microfibrils and concentration of polymers and this structure impacts strength and stiffness. The objective of this study was to use near infrared spectroscopy and X-ray diffraction to determine the effect of lignin and cellulose associated wavelengths, microfibril angle, density, and radial p...
A method based on FT-Raman spectroscopy is proposed for determining in situ concentrations of ethylenic resi dues in softwood lignin. Raman contributions at 1133 and 1654 cm-1, representing coniferaldehyde and coni feryl alcohol structures, respectively, were used in quan tifying these units in spruce wood with subsequent conversion to concentrations in lignin. For coniferalde hyde units, t...
In dilute acid pretreatment of lignocellulosic biomass, lignin has been shown to form droplets that deposit on the cellulose surface and retard enzymatic digestion of cellulose (Donohoe et al., 2008; Selig et al., 2007). However, studies of this nature are limited for hydrothermal pretreatment, with the result that the corresponding mechanisms that inhibit cellulosic enzymes are not well unders...
The properties and capacities of the ligninolytic enzymes of Daedaleopsis spp. are still unknown. This is the first study on the effect of plant residues and period of cultivation on the properties of Mn-oxidizing peroxidases and laccases of D. confragosa and D. tricolor, as well as their ligninolytic potentials. Wheat straw was the optimal carbon source for synthesis of highly active Mn-depend...
We have discovered a mutant loblolly pine (Pinus taeda L.) in which expression of the gene encoding cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.195) is severely reduced. The products of CAD, cinnamyl alcohols, are the precursors of lignin, a major cell wall polymer of plant vascular tissues. Lignin composition in this mutant shows dramatic modifications, including increased incorporation of t...
This study was to explore the conversion of low-cost bio-residuals into high value-added cellulose nanocrystals. Two enzymatic hydrolyzed residuals (i.e., HRMMW and HRSPW) were collected from two different bio-ethanol producing processes-hydrolyzing medium-milled wood (MMW) and hydrolyzing acid sulfite pretreated wood (SPW), respectively. The results showed that both residuals contained over 20...
A lignin-epoxy resin composite was prepared by blending lignin/wood flour with an epoxy resin and polyamine. The effects of the wood flour on the mechanical, thermal creep, and creep recovery properties, as well as the microstructure of the composite, were studied. Among the mechanical properties, the initial modulus increased with increasing content of wood flour. The glass transition temperat...
Near infrared (NIR) spectroscopy method was introduced to measure the lignin content in Acacia species. Acid-soluble lignin, Klason lignin, and total lignin contents from 78 wood meal samples of Acacia spp. trees grown in Guangxi province with different ages, height, and families were measured by wet chemistry. NIR spectra were also collected using a Bruker MPA spectrometer within 4000-12500cm ...
Several different enzymatic, chemical and mechanical methods have been developed for the isolation of lignin from wood and pulp. However, due to the heterogeneous nature of wood and pulp fibers and the heterogeneity that exists between individual fibers, no method is currently available for the quantitative isolation of native or residual lignin without the risk of structural changes during the...
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