An Empirical Method for Estimating the Degree of Crystallinity of Native Cellulose Using the X-Ray Diffractometer

Segal, Leon; Creely, Joseph J.; Martin, A.E.; Conrad, Carl M.

doi:10.1177/004051755902901003

Cited by 6,513 publications

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“…Data were analyzed employing X'Pert HighScore software. The crystallinity index, %Ic(XRD), was calculated at several temperatures using the equation proposed by Segal [38]:…”

Section: Methodsmentioning

confidence: 99%

Comparison of thermal behavior of natural and hot-washed sisal fibers based on their main components: Cellulose, xylan and lignin. TG-FTIR analysis of volatile products

et al. 2014

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Abstract:This paper presents in a comprehensive way the thermal behavior of natural and hot-.washed sisal fibers, based on the fundamental components of lignocellulosic materials: cellulose, xylan and lignin. The research highlights the influence exerted on the thermal stability of sisal fibers by other constituents such as non-cellulosic polysaccharides (NCP) and mineral matter. Thermal changes were investigated by thermal X-ray diffraction (TXRD), analyzing the crystallinity index (%Ic) of cellulosic samples, and by simultaneous thermogravimetric and differential thermal analysis coupled with Fourier-transformed infrared spectrometry (TG/DTA-FTIR), which allowed to examine the evolution of the main volatile compounds evolved during the degradation under inert and oxidizing atmospheres. The work demonstrates the potential of this technique to elucidate different steps during the thermal decomposition of sisal, providing extensible results to other lignocellulosic fibers, through the analysis of the evolution of CO 2 , CO, H 2 O, CH 4 , acetic acid, formic acid, methanol, formaldehyde and 2-butanone, and comparing it with the volatile products from pyrolysis of the biomass components. The hydroxyacetaldehyde detected during pyrolysis of sisal is indicative of an alternative route to that of levoglucosan, generated during cellulose pyrolysis.Hot-washing at 75 ºC mostly extracts non-cellulosic components of low decomposition temperature, and reduces the range of temperature in which sisal decomposition occurs, causing a retard in the pyrolysis stage and increasing Tb NCP and Tb CEL , temperatures at the maximum mass loss rate of non-cellulosic polysaccharides and cellulose decompositions, respectively. However, enriching sisal fibers in cellulose produces a decrease of Tb CEL under an oxidizing atmosphere, and furthermore, a delay of the combustion process, displacing Tb COM to higher temperatures.The results and findings of the paper would help further understanding of thermal processes where agave fibers are involved, as the decomposition of their composites.

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“…Data were analyzed employing X'Pert HighScore software. The crystallinity index, %Ic(XRD), was calculated at several temperatures using the equation proposed by Segal [38]:…”

Section: Methodsmentioning

confidence: 99%

Comparison of thermal behavior of natural and hot-washed sisal fibers based on their main components: Cellulose, xylan and lignin. TG-FTIR analysis of volatile products

et al. 2014

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“…O índice de cristalinidade (Ic) da celulose foi calculado através da equação: Ic = 1 -I 1 / I 2 [7,30,31] , onde I 1 = intensidade do mínimo de difração, relacionada à parte amorfa (2θ = 18,8°) e I 2 = intensidade do máximo de difração, relacionada à parte cristalina (2θ = 22,4°). Este método foi desenvolvido por Segal e colaboradores [30] e tem sido largamente utilizado para o estudo de fibras naturais [7,9,10,[31][32][33][34][35] .…”

Section: Methodsunclassified

Caracterização química e estrutural de fibra de sisal da variedade Agave sisalana

et al. 2009

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e beneficiamento da fibra e termina com a industrialização e confecção de artesanato [1,2,[4][5][6] .A planta do sisal é originária da península de Yucatã, no México, tendo recebido este nome de uma erva nativa chamada zizal-xiu [4] . Em 1834, as primeiras mudas foram levadas para o sul da Flórida (EUA) e a partir de 1892 começaram a ser cultivadas na África. No Brasil, as primeiras mudas de Agave sisalana Perrine foram introduzidas na Bahia em 1903, sendo esta a única espécie do gênero Agave cultivada comercialmente no país [5][6][7] . As fibras são extraídas das folhas, que possuem de 8 a 10 cm de largura e de 150 a 200 cm de comprimento. Da folha se obtém de 3 a 5% do seu peso em fibra. Os 95 a 97% restantes constituem os chamados resíduos do beneficiamento, que são utilizados como adubo orgânico, ração animal e pela indús-tria farmacêutica. As fibras são constituídas de fibrilas ou IntroduçãoO sisal é a principal fibra dura produzida no mundo, correspondendo a aproximadamente 70% da produção comercial de todas as fibras desse tipo. No Brasil, o cultivo do sisal se concentra na região Nordeste, sendo os estados da Bahia, Paraíba e Rio Grande do Norte os principais produtores, com 93,5, 3,5 e 3,0%, respectivamente, da produção nacional [1][2][3] . A agaveicultura se concentra em áreas de pequenos produtores, com predomínio do trabalho familiar. O sisal, além de constituir fonte de renda e emprego para um grande contingente de trabalhadores, é um importante agente de fixação do homem à região semi-árida nordestina, sendo, em algumas dessas regiões, a única alternativa de cultivo com resultados econômicos satisfatórios. A fibra do sisal, beneficiada ou industrializada, representa cerca de 80 milhões de dólares em divisas para o Brasil, além de gerar mais de meio milhão de empregos diretos e indiretos por Resumo: Nos últimos anos, o interesse pelo uso de fibras naturais em materiais compósitos poliméricos tem aumentado significativamente. Neste trabalho foram investigadas as propriedades, químicas, físicas, térmicas e estruturais da fibra de sisal brasileira da variedade Agave sisalana. Nosso objetivo foi avaliar a qualidade e o desempenho desta fibra para aplicações industriais. Foram realizados ensaios de resistência à tração, análise da composição química, difração de raios X, e estudos por microscopia eletrônica de varredura (MEV) ao longo do comprimento da fibra. A fibra de sisal brasileira apresentou propriedades mecânicas e térmicas dentro da faixa relatada na literatura, mostrando-se adequada para ser utilizada em materiais compósitos poliméricos. Palavras-chave: Fibras naturais, compósitos, composição química, caracterização. Chemical and Structural Characterization of Sisal Fibers from Agave sisalana VarietyAbstract: In recent years, the interest in the use of natural fibers in polymeric composite materials has increased significantly. In this work were investigated the structural, thermal, chemical, and physical properties of Brazilian sisal fiber from Agave sisalana variety. Our aim was to evaluate th...

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“…They are also becoming more cost-effective as compared to other pretreatment options (George et al 2015). ILs are efficient for biomass dissolution, which is typically reported as a change in crystallinity index (CrI) (Kumar et al 2009;Segal et al 1959;Thygesen et al 2005). For example, the degrees of crystallinity in cellulose reconstituted after being dissolved in 1-allyl-3-methylimidazolium chloride ([C 3 C 1 Im]Cl) and 1-butyl-3-methylimidazolium chloride ([C 4 C 1 Im]Cl) were lower than untreated cellulose, resulting in an increased accessibility of the polysaccharide chains to cellulases (Dadi et al 2007;Dadi et al 2006;Liu and Chen 2006).…”

Section: Introductionmentioning

confidence: 99%

Ionic liquid-tolerant microorganisms and microbial communities for lignocellulose conversion to bioproducts

Simmons

Singer

et al. 2016

Appl Microbiol Biotechnol

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Chemical and physical pretreatment of biomass is a critical step in the conversion of lignocellulose to biofuels and bioproducts. Ionic liquid (IL) pretreatment has attracted significant attention due to the unique ability of certain ILs to solubilize some or all components of the plant cell wall. However, these ILs not only inhibit enzyme activities, but also the growth and productivity of microorganisms used in downstream hydrolysis and fermentation processes.While pretreated biomass can be washed to remove residual IL and reduce inhibition, extensive washing is costly and not feasible in large-scale processes. IL tolerant microorganisms and microbial communities have been discovered from environmental samples and studies begun to elucidate mechanisms of IL tolerance. The discovery of IL tolerance in environmental microbial communities and individual microbes has lead to the proposal of molecular mechanisms of resistance. In this article, we review recent progress on discovering IL tolerant microorganisms, identifying metabolic pathways and mechanisms of tolerance, and engineering microorganisms for IL tolerance. Research in these areas will yield new approaches to overcome inhibition in lignocellulosic biomass bioconversion processes and increase opportunities for the use of ILs in biomass pretreatment.

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An Empirical Method for Estimating the Degree of Crystallinity of Native Cellulose Using the X-Ray Diffractometer

Cited by 6,513 publications

References 17 publications

Comparison of thermal behavior of natural and hot-washed sisal fibers based on their main components: Cellulose, xylan and lignin. TG-FTIR analysis of volatile products

Comparison of thermal behavior of natural and hot-washed sisal fibers based on their main components: Cellulose, xylan and lignin. TG-FTIR analysis of volatile products

Caracterização química e estrutural de fibra de sisal da variedade Agave sisalana

Ionic liquid-tolerant microorganisms and microbial communities for lignocellulose conversion to bioproducts

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