scholarly journals Assessing the enzymatic effects of cellulases and LPMO in improving mechanical fibrillation of cotton linters

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Cristina Valls ◽  
F. I. Javier Pastor ◽  
M. Blanca Roncero ◽  
Teresa Vidal ◽  
Pilar Diaz ◽  
...  
Cellulose ◽  
2021 ◽  
Author(s):  
María González Martínez ◽  
Nathalie Marlin ◽  
Denilson Da Silva Perez ◽  
Capucine Dupont ◽  
Carolina del Mar Saavedra Rios ◽  
...  

2020 ◽  
pp. 1-14
Author(s):  
Јovana Milanovic ◽  
Тijana Lazic ◽  
Irena Zivkovic ◽  
Маrija Vuksanovic ◽  
Milena Milosevic ◽  
...  

2013 ◽  
Vol 856 ◽  
pp. 309-313 ◽  
Author(s):  
Anupama Kaushik ◽  
Alka Garg

In this study the castor oil based polyurethane (PU) nanocomposites were prepared by dispersing the cellulose nanocrystallites (CNC) isolated from cotton linters. CNC was dispersed in PU matrix using ultrasonicator coupled with high shear homogenizer. The filler loading was varied from 0-10% of the total weight of the mixture. The PU/CNC nanocomposites were characterized by SEM, XRD, FTIR, mechanical and barrier properties. SEM confirmed homogeneous dispersion of CNCs in polyurethane matrix with small agglomerates at certain places. Improvement in mechanical properties was observed as compared to neat PU. Diffusivity and permeability of the nanocomposites was reduced at higher loadings of CNC.


1923 ◽  
Vol 15 (8) ◽  
pp. 819-822
Author(s):  
William F. Henderson

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Masoumeh Hassanzadeh ◽  
Ronald Sabo ◽  
Alan Rudie ◽  
Richard Reiner ◽  
Roland Gleisner ◽  
...  

TEMPO nanofibrillated cellulose (TNFC) from two underutilized Appalachian hardwoods, Northern red oak (Quercus rubra) and yellow poplar (Liriodendron tulipifera), was prepared to determine its feasibility to be used as template for antimicrobial metallic copper particles. In addition, a comparison of the TNFC from the two species in terms of their morphological, chemical, thermal, and mechanical properties was also performed. The woody biomass was provided in the form of logging residue from Preston County, West Virginia. A traditional kraft process was used to produce the pulp followed by a five-stage bleaching. Bleached pulps were then subjected to a TEMPO oxidation process using the TEMPO/NaBr/NaClO system to facilitate the final mechanical fibrillation process and surface incorporation of metallic copper. The final TNFC diameters for red oak and yellow poplar presented similar dimensions, 3.8±0.74 nm and 3.6±0.85 nm, respectively. The TNFC films fabricated from both species exhibited no statistical differences in both Young’s modulus and the final strength properties. Likely, after the TEMPO oxidation process both species exhibited similar carboxyl group content, of approximately 0.8 mmol/g, and both species demonstrated excellent capability to incorporate antimicrobial copper on their surfaces.


Holzforschung ◽  
2007 ◽  
Vol 61 (5) ◽  
pp. 504-508 ◽  
Author(s):  
Alain Castellan ◽  
Reinaldo Ruggiero ◽  
Elisabete Frollini ◽  
Ludmila A. Ramos ◽  
Christine Chirat

Abstract Steady-state fluorescence emission spectra of various celluloses were measured at an excitation wavelength of 320 nm. Various spectra recorded in the solid state were compared: (1) ECF bleached papers made of hardwood, the anhydroglucose units of which were chemically modified at C1 and C6 or C2 and C3 positions with carboxylic groups; (2) microcrystalline cellulose; (3) cotton linters; and (4) delignified sisal fibers (mercerized or not). Fluorescence emission was quite independent of the carboxylic acid content and average molecular weight (determined by viscosimetry) of the cellulose polymers. Microcrystalline cellulose (Avicel), cotton linters, and mercerized delignified sisal cellulose were acetylated in homogeneous medium (DMAc/LiCl as solvent system) to obtain soluble polymers in dichloromethane for comparison of spectra recorded in the solid and liquid states. Fluorescence of cellulose acetates in solution (CH2Cl2) and in the solid state was compared under similar experimental conditions to non-esterified celluloses in the solid state. The importance of the solid state for fluorescence emission could be demonstrated. Fluorophores are present in minute amounts in the polymer and their favorable energy transfer for excitation in the solid state likely enhances fluorescence emission. Among numerous fluorophores, dityrosine appeared to be a good candidate for fluorescence because it displayed emission in the fluorescence range of cellulose. Dityrosine is an amino acid involved in the lignification of non-woody plants. Mercerized sisal impregnated with tyrosine in the presence of peroxidase and hydrogen peroxide did not show enhanced emission, in contrast to para-hydroxycinnamic acid (coumaric acid), which is also involved in the lignification process at least for non-woody plants. The origin of cellulose fluorescence remains uncertain and appears to have several origins. This study clearly underlines the importance of the solid state for enhancing fluorophore emission.


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