Abstract Sugar cane bagasse and curaua acidolysis lignins were used to get a better understanding of the mechanism involved in a new chemical modification of sugar cane bagasse and curaua fibres, consisting in a selective oxidation of lignin by chlorine dioxide and reacting some of the created unsaturated units (quinones or muconic derivatives) with furfuryl alcohol (FA). The objective of the treatment was to create a fibre coating increasing compatibility between fibres and phenolic resins in composites. The lignins were reacted with chlorine dioxide to oxidize the phenolic units of the polymer and then treated with furfuryl alcohol. Weight percent gain of 14% and 10% were obtained for sugar cane bagasse and curaua, respectively. 1 H and 31 P NMR, as well as FT-IR results showed that bagasse lignin had more guaiacyl than syringyl units and the reverse for curaua lignin. 1 H NMR of oxidized lignins revealed a decrease of the aromatic and methoxy content after the ClO 2 oxidation, due to partial degradation of the macromolecule. Thermal analysis showed that sugar cane lignin decomposes at lower temperature than curaua lignin, partly due to the high content of condensed structural units present in curaua lignin. Condensed units decompose at higher temperatures than uncondensed ones. The reaction of oxidized lignin with FA shifted the decomposition exotherm to lower temperature for both curaua and sugar cane bagasse lignins, due to the modification introduced into their structures.
Functional natural polymers - a new dimensional creativity in lignocellulosic chemistry chemical structures of cellulose, hemicelluloses and lignin reactivity and accessibility of cellulose, hemicellulose and lignins chemical modification of cellulose chemical modification of lignin chemical modification of solid wood liquefaction of wood surface modification and activation of wood chemical modification of nonwood lignocellulosics characterization of chemically modified wood weathering of chemic...
Abstract Treatment of the dewaxed wheat straw with 0.5 M KOH at 35°C for 2.5 h without ultrasonic irradiation and with ultrasound assistance for 5, 10, 15, 20, 25, 30, and 35 min resulted in a dissolution of 43.9%, 43.9%, 43.9%, 44.4%, 44.4%, 45.6%, 46.8%, and 49.1% of the original lignin, respectively. Much better results were achieved under the ultrasonic irradiation time for 35 min where nearly 50% of the original lignin was solubilized at 35°C for 2.5 h. The purity of the lignin preparations...
Lignin, extracted from sugarcane bagasse by the organosolv process, was used as a partial substitute of phenol (40 w/w) in resole phenolic matrices. Short sugarcane fibers were used as reinforcement in these polymeric matrices to obtain fiber-reinforced composites. Thermoset polymers (phenolic and lignophenolic) and related composites were obtained by compression molding and characterized by mechanical tests such as impact, differential mechanical thermoanalysis (DMTA), and hardness tests. The i...
To define the abundance and comprehend the reactivity of dibenzodioxocins in lignin, model compound studies, specific degradation experiments on milled wood lignin, and molecular modeling calculations have been performed. Quantitative 31P NMR measurements of the increase of biphenolic hydroxyl groups formed after a series of alkaline degradations in the presence of hydrosulfide anions (kraft conditions) showed the presence of 3.7 dibenzodioxocin rings/100 C9 units in milled wood lignin. The DFRC...
Abstract Soda lignin from black liquors of Alfa grass was precipitated with hydrochloric acid at pH 2 and 4.5, and with sulfuric acid at pH 4.5. The molecular structures of the lignins were analyzed for the first time. The phenolic structures were studied using UV-visible spectroscopy and 31 P-NMR spectrometry. The lignin fragments were also analyzed by size exclusion chromatography and β- O -4 bond content was determined by thioacidolysis. The total phenolic content was found to be low for annu...
Thermal decomposition under nitrogen of sugarcane bagasse, petroleum residue and their blends was studied by thermogravimetry (TG) at different heating rates (10, 20, 40 and 60°C/min). Thermal decomposition kinetic parameters were determined. Sugarcane bagasse pyrolysis was described as the sum of cellulose, hemicellulose, and lignin individual contributions. First order equations were used to determine the bagasse component thermal decomposition kinetics. Activation energies calculated were 235...
Abstract The evolution of water during the heating of cellulose is of great importance in understanding the degradation of cellulose because of the autoaccelerating role water plays in the degradation process. Water evolution from cellulose occurs both physically through desorption and chemically by elimination reactions. This paper discusses the mechanisms of water evolution from cellulose in three distinct temperature regimes: (i) loss of absorbed water at low temperatures ( 550°C). The evolut...
Abstract The impact performance of chopped bagasse–EVA matrix composites is evaluated and compared with the behavior of bagasse filled PP and PE matrix composites and wood-based materials. The volume fraction and size of the chopped bagasse used as filler was varied. The experimental results show that the incorporation of bagasse strongly reduces the deformation capacity of EVA polymer. The reduction of the deformation capacity of the composites was also inferred by solid-state NMR relaxation an...
Vegetable fibers like cotton, sisal, and sugar cane bagasse have been used as reinforcement in a polymeric matrix. Because of its low cost and affinity with lignocellulosic fibers, a phenol-formaldehyde resin —resol— was selected as the matrix. Composites were prepared by compression molding. The influence of fiber volume fraction-Vf-in flexural properties and density of composites has been studied. Cotton and sugar cane bagasse composites present a Vf value at which flexural strength and modulu...
Abstract Exotherms in the DSC analysis of wood and its components have been assigned using Akamatsu wood ( Pinus densiflora ). Analysis of wood powder indicated two exotherms at around 340 and 475°C. Among isolated components galactoglucomannan has a single exotherm at around 330–360°C, and other commercial amorphous polysaccharides are in the range of 300–370°C. Therefore, the transition at around 340°C in wood thermogram was considered to be due to polysaccharides. On the other hand, the tempe...
Sugarcane (Saccharum officinarum) bagasse (SCB) is a biomass of agricultural waste obtained from sugarcane processing that has been found in abundance globally. Due to its abundance in nature, researchers have been harnessing this biomass for numerous applications such as in energy and environmental sustainability. However, before it could be optimally utilised, it has to be pre-treated using available methods. Different pre-treatment methods were reviewed for SCB, both alkaline and alkali–acid ...
The utilization of sugarcane bagasse (SB) in fermentation requires pretreatment processes to render fermentable components available to microorganisms. Pretreatment by using ionic liquids (ILs) is considered promising but the high cost is an impediment in its adoption, therefore, a mixture of IL pretreated and untreated SB was utilized to obtain bacterial multienzyme under solid-state fermentation (SSF). Bacillus aestuarii UE25, a thermophilic strain was utilized for that purpose. Fermentation c...
Induction motors, acting as work house of industries, are affected by winding temperature due to poor insulation. In producing a sustainable polymer composite electrical insulator, this article gets into the investigative study of tensile strength, hydrophobicity, hardness and the electrical breakdown properties of silicone rubber (SR) reinforced with sugarcane bagasse ash (SCBA). In order to identify optimal proportion, various filler proportions are studied for mechanical, physical, tensile an...
Last. Ahmad Fudholi(UKM: National University of Malaysia)H-Index: 23
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Abstract null null Understanding the basic properties of natural fibers is important to determine the optimal intended uses for instance as high-quality bio-composite raw material. This review describes the characteristics, and potential uses of some natural fibers in order to improve their sustainability and economic values. The natural fibers have low density and high strength to weight ratio and reduction make them potential as light weight composite and reinforcement materials. The microstru...
A mixture of cyclohexyl methyl ethers was prepared from Kraft lignin pyrolysis oil for use as a biomass-derived aliphatic solvent. Using Kamlet–Taft solvatochromic parameters, it was determined that the solvent mixture is somewhat more basic and polar than cyclopentyl methyl ether. Neither the biomass-derived solvent nor pure cyclohexyl methyl ether formed any detectable peroxides in 12 weeks of exposure to air, even though THF formed peroxides rapidly under such conditions. This mixture can be ...
Last. Roohollah Talebitooti(IUST: Iran University of Science and Technology)H-Index: 21
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Both natural and synthetic fibers do not perform well at low frequencies and are also subjected to erosion, moisture, fire, etc., when used as an interior finish of room walls. To overcome these pr...
#1Roberta Motta Neves(UFRGS: Universidade Federal do Rio Grande do Sul)H-Index: 8
#2Heitor Luiz Ornaghi(UFRGS: Universidade Federal do Rio Grande do Sul)H-Index: 16
Last. Sandro Campos Amico(UFRGS: Universidade Federal do Rio Grande do Sul)H-Index: 36
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Abstract Cellulose and its derivatives are widely explored for films and thickening of pharmaceutical solutions, in paints, as reinforcement in composites, among others. This versatility is due to advantages such as renewability, low cost, and environmental friendliness. When used in polymer composites, due to the hydrophilic character of the cellulose, surface chemical modification is highly recommended to improve its compatibility with the polymeric matrix. Hence, this paper presents a systema...
A fractionation scheme for lignocellulosic biomass where major constituent biopolymers are recovered in applicable forms is essential for integrated biorefinery. In this study, a sequential two-step fractionation of sugarcane bagasse using liquid hot water followed an organic acid-catalyzed aqueous glycerol-based organosolv process was developed. Under optimal conditions, 66.1% of the hemicellulose was recovered as saccharides by the acid-catalyzed hydrothermal step. Formic acid was superior to ...
