نتایج جستجو برای: cellulose properties
تعداد نتایج: 893779 فیلتر نتایج به سال:
BACKGROUND The bioconversion of cellulose into simple sugars or chemicals has attracted extensive attention in recent decades. The crystal allomorphs of cellulose are key factor affecting cellulose saccharification. However, due to the influence of lignin, hemicelluloses, and different characterization methods in the literature, the effect of cellulose allomorphs on cellulose saccharification i...
Two approaches for creating a new all-cellulose composite material have been studied: the biosynthesis of compartmentalised bacterial cellulose fibril aggregates and the compression moulding of commercial chemical wood pulps processed with only water. The objective was to study the structural changes during processing and the complexity of relating the mechanical properties of the final biocomp...
Quartz crystal microgravimetry (QCM) was used to investigate the interactions between cellulase enzymes and model cellulose substrates. The substrates consisted of thin films of cellulose that were spin-coated onto polyvinylamine (PVAm) precoated quartz crystal sensors carrying conductive gold surfaces. In QCM the quartz crystals are piezoelectrically driven and the frequency and dissipation sh...
pollution arising from plastic waste materials caused a great worry for researchers who are interested in protection of environment. this problem shifts their subject to bio-polymers for applications in packaging industries. however, their low water barrier properties are a critical problem. the effects of citric acid and methyl cellulose on water vapor and oxygen permeabilities and mechanical ...
cellulose wastes of a wood and paper factory were used to produce activated carbon. several chemical agents under various conditions were used for production of activated carbon and hence their adsorption properties have been evaluated. in addition the effect of process parameters such as raw material, chemical agent concentration, impregnation ratio, carbonization temperature, carbonization ti...
fe3o4 nanoparticles were synthesizedviaa simple chemical reaction between fecl2.4h2o and fe(no3)3.9h2o under nitrogen atmosphere at room temperature, and then nanoparticles were added to cellulose acetate (ca) polymer. the influence of nanoparticles on the thermal properties of ca polymeric matrix was studied using thermogravimetric analysis (tga). nanostructures were characterized by x-ray dif...
An earlier safety assessment of several cellulose polymers has been expanded to include cellulose itself and other cellulose polymers used in cosmetics. In general, these ingredients are modified cellulose polymers formed by reaction with the free hydroxyl groups in cellulose. The number of hydroxyl groups reacting, as well as the nature of the substitute group, largely determine the physical p...
The current examples of natural-fiber based polymer composites, because of their biobased and biodegradable properties, offer an alternative as a ‘green’ material available for automotive and other engineering applications. However such composites suffer from low strength and fatigue properties compared to the carbonor glass-fiber based polymer composites. Cellulose nanofibers (CNFs), a new typ...
Atomic force microscopy (AFM) and Fourier transformation infrared (FT-IR) spectroscopy was used for assessment of structural differences of celluloses of various origins. Investigated celluloses were: bacterial celluloses cultured in presence of pectin and/or xyloglucan, as well as commercial celluloses and cellulose extracted from apple parenchyma. The crystallinity index (XC%) varied from 25 ...
The bacteria Fibrobacter succinogenes, Ruminococcus flavefaciens, and Ruminococcus albus generally are regarded as the predominant cellulolytic microbes in the rumen. Comparison of available data from the literature reveals that these bacteria are the most actively cellulolytic of all mesophilic organisms described to date from any habitat. In light of numerous proposals to improve microbial ce...
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