File Name: on the determination of crystallinity and cellulose content in plant fibres doi.zip
Bo Madsen, E. The work on cellulose fiber composites is typically strictly divided into two separated research fields depending on the fiber origin, that is, from wood and from annual plants, representing the two different industries of forest and agriculture, respectively. The present paper evaluates in parallel wood fibers and plant fibers to highlight their similarities and differences regarding their use as reinforcement in composites and to enable mutual transfer of knowledge and technology between the two research fields.
- Wood versus Plant Fibers: Similarities and Differences in Composite Applications
- On the determination of crystallinity and cellulose content in plant fibres
- Physical and Chemical Modifications of Plant Fibres for Reinforcement in Cementitious Composites
The susceptibility and characteristics of biological degradation of lignocellulosic fibers, such as sisal fibers, are presented in this study using a modified soil burial test SBT protocol. Observation of the results indicated that biodegradation of the fibers was predominated by enzymatic hydrolysis of amorphous materials followed by degradation of crystalline cellulose.
A comparative study of cellulose crystallinity based on the sample crystallinity and the cellulose content in plant fibres was performed for samples of different origin. Strong acid hydrolysis was found superior to agricultural fibre analysis and comprehensive plant fibre analysis for a consistent determination of the cellulose content. Crystallinity determinations were based on X-ray powder diffraction methods using side-loaded samples in reflection Bragg-Brentano mode. This was shown to be straightforward to use and in many ways advantageous to traditional crystallinity determinations using the Segal or the Ruland—Vonk methods. These findings are significant in relation to strong fibre composites and bio-ethanol production.
Wood versus Plant Fibers: Similarities and Differences in Composite Applications
On the determination of crystallinity and cellulose content in plant fibres
Metrics details. Although measurements of crystallinity index CI have a long history, it has been found that CI varies significantly depending on the choice of measurement method. In this study, four different techniques incorporating X-ray diffraction and solid-state 13 C nuclear magnetic resonance NMR were compared using eight different cellulose preparations. We found that the simplest method, which is also the most widely used, and which involves measurement of just two heights in the X-ray diffractogram, produced significantly higher crystallinity values than did the other methods. Data in the literature for the cellulose preparation used Avicel PH support this observation.
Metrics details. Calotropis procera fiber CPF is the fruit fiber of C. In this study, Calotropis procera fiber CPF was first purified in the pretreatment process including delignification and bleaching before the isolation of cellulose nanocrystal. It was composed of The morphology of the Calotropis procera fiber and fiber after each pretreatment process was also investigated. Cellulose nanocrystal was extracted by classical sulfuric acid hydrolysis of the pretreated Calotropis procera fiber.
Some species of bacteria secrete it to form biofilms. Cellulose is mainly used to produce paperboard and paper. Smaller quantities are converted into a wide variety of derivative products such as cellophane and rayon. Conversion of cellulose from energy crops into biofuels such as cellulosic ethanol is under development as a renewable fuel source. Cellulose for industrial use is mainly obtained from wood pulp and cotton. Some animals, particularly ruminants and termites , can digest cellulose with the help of symbiotic micro-organisms that live in their guts, such as Trichonympha. In human nutrition , cellulose is a non-digestible constituent of insoluble dietary fiber , acting as a hydrophilic bulking agent for feces and potentially aiding in defecation.
Physical and Chemical Modifications of Plant Fibres for Reinforcement in Cementitious Composites
На загрузку программы и поиск вируса уйдет минут пятнадцать. Скажи, что ничего нет, - прошептал. - Абсолютно. Скажи папе, что все в порядке.
Думаю, англичанка. И с какими-то дикими волосами - красно-бело-синими. Беккер усмехнулся, представив это зрелище.
Он, как обычно, записал имена жертв. Контакты на кончиках пальцев замкнулись, и на линзах очков, подобно бестелесным духам, замелькали буквы. ОБЪЕКТ: РОСИО ЕВА ГРАНАДА - ЛИКВИДИРОВАНА ОБЪЕКТ: ГАНС ХУБЕР - ЛИКВИДИРОВАН Тремя этажами ниже Дэвид Беккер заплатил по счету и со стаканом в руке направился через холл на открытую террасу гостиницы. - Туда и обратно, - пробормотал .
Вернулся ли Дэвид.