Artykuły w czasopismach na temat „Cellulose fibres”
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Ouajai, Sirisart, Peerachai Ruangwilairat, Kitti Ongwongsakul, Thanawadee Leejarkpai i Robert A. Shanks. "Morphology and Structure of Modified Oil Palm Empty Fruit Bunch Cellulose Fibre". Advanced Materials Research 93-94 (styczeń 2010): 607–10. http://dx.doi.org/10.4028/www.scientific.net/amr.93-94.607.
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Oil palm empty fruit bunch (OPEFB) cellulose fibre has been widely used as a reinforcing filler in polymer composites. Surface modification of OPEFB fibre was aimed enhancing inter-phase adhesion with a poly(lactic acid) matrix. In this study, the OPEFB fibres were pre-treated in a sodium hydroxide solution. Surface compositions and thermal stability of the fibres were studied using ATR-FTIR and TGA techniques, respectively. The pre-treatment resulted in the removal of non-cellulosic components leaving purer fibres. In addition, an acetylation of OPEFB cellulose fibres by acetic anhydride was conducted under solvent free condition at room temperature (30 °C). The acetylation reaction was catalyzed by iodine. The degree of substitution monitored by solid state 13C NMR depended upon reaction time and molar ratio of OPEFB cellulose and acetic anhydride. Crystalline structure and morphology of the partial acetylated fibres were investigated using WAXD and SEM, respectively.
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Fernando, Sarah, Chamila Gunasekara, Amin Shahpasandi, Kate Nguyen, Massoud Sofi, Sujeeva Setunge, Priyan Mendis i Md Tareq Rahman. "Sustainable Cement Composite Integrating Waste Cellulose Fibre: A Comprehensive Review". Polymers 15, nr 3 (19.01.2023): 520. http://dx.doi.org/10.3390/polym15030520.
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This review presents the research conducted to date in the field of cement-based composites reinforced with waste paper-based cellulose fibres, focusing on their composition, mechanical properties, and durability characteristics. The literature demonstrates that the properties of raw material (depending on their own chemical composition) significantly influence the formation of the cement composite binders. When considering fresh properties, the presence of silica and magnesium compounds generally lead to favourable effects on the setting of the cement composite when combined with waste paper cellulose fibre. Reduction in density values, i.e., approximately 25%, was observed with the inclusion of waste paper fibres from 20 to 80% in cement composites. The homogeneous dispersion of fibres in the matrix is one of the crucial factors to achieve in order to develop composites with well-balanced mechanical properties incorporating waste paper cellulose fibres. Hence, dispersion of fibres can be improved by increasing water quantity corresponding to the optimal value, which was a water/cement ratio of 0.64 leading to optimum strength properties of the composite. Even though the effect of fibre dispersion in the matrix improves with the addition of water, higher porosity and voids govern the strength properties beyond an optimum water-to-cement ratio. Higher porosity leads to an increase in the water absorption and a lowering of the thermal conductivity properties with the addition of paper fibre in cement binders. Paper fibre absorbs a high amount of water leading to higher water absorption. This phenomenon is related to the hydrophilic nature of cellulosic fibres absorbing some volume of water due to their microporous structure.
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Manian, Avinash P., Sophia Müller, Doris E. Braun, Tung Pham i Thomas Bechtold. "Dope Dyeing of Regenerated Cellulose Fibres with Leucoindigo as Base for Circularity of Denim". Polymers 14, nr 23 (2.12.2022): 5280. http://dx.doi.org/10.3390/polym14235280.
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Circularity of cellulose-based pre- and post-consumer wastes requires an integrated approach which has to consider the characteristics of the fibre polymer and the presence of dyes and additives from textile chemical processing as well. Fibre-to-fibre recycling is a condition to avoid downcycling of recycled material. For cellulose fibres regeneration via production of regenerated cellulose fibres is the most promising approach. Textile wastes contain dyes and additives, thus a recycling technique has to be robust enough to process such material. In an ideal case the reuse of colorants can be achieved as well. At present nearly 80% of the regenerated cellulose fibre production utilises the viscose process, therefore this technique was chosen to investigate the recycling of dyed material including the reuse of the colorant. In this work, for the first time, a compilation of all required process steps to a complete circular concept is presented and discussed as a model. Indigo-dyed viscose fibres were used as a model to study cellulose recycling via production of regenerated cellulose fibres to avoid downcycling. Indigo was found compatible to the alkalisation and xanthogenation steps in the viscose process and blue coloured cellulose regenerates were recovered from indigo-dyed cellulose. A supplemental addition of reduced indigo to the cellulose solution was also found feasible to adjust colour depth in the regenerated cellulose to the level required for use as warp material in denim production. By combination of fibre recycling and indigo dyeing the conventional yarn dyeing in denim production can be omitted. Model calculations for the savings in water and chemical consumption demonstrate the potential of the process. The proportion of the substitution will depend on the collection rate of denim wastes and on the efficiency of the fibre regeneration process. Estimates indicate that a substitution of more than 70% of the cotton fibres by regenerated cellulose fibres could be achieved when 80% of the pre- and post-consumer denim wastes are collected. Therefore, the introduction of fibre recycling via regenerated cellulose fibres will also make a substantial impact on the cotton consumption for jeans production.
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Fuckerer, Katharina, Oliver Hensel i Joachim J. Schmitt. "Rye Bread Fortified With Cellulose and Its Acceptance by Elderlies in Nursing Homes and Young Adults". Journal of Food Studies 5, nr 1 (27.01.2016): 1. http://dx.doi.org/10.5296/jfs.v5i1.8847.
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<p>Several clinical studies suggest that a sufficient daily intake of fibres has positive effects on prevention of different diseases. Other studies show that most elderlies ingest too less fibres daily. As bread is one of the daily consumed food by elderly a brown rye bread fortified with three different cellulose fibres length (18 µm, 300 µm, 700 µm) was developed. To find out whether elderly would consume such cellulose fortified rye breads, preference tests and a questionnaire about fibres and liking of fibres enriched rye breads were conducted with people older than 75 years and living in a nursing home. Comparable test were conducted with young adults. Preference test and questionnaire showed that young adults favoured rye bread with 18 µm cellulose, because they associated soft crumb texture with freshly baked bread. Instead elderlies preferred standard rye bread and bread with 300 µm cellulose, because those two kinds of rye breads have similar crumb texture which is popular with elderlies. These results showed that there are differences in preferring of fortified rye bread between elderlies and young adults. Parallel questionnaires showed that elderlies and young are well informed about fibres and have a positive attitude towards rye bread fortified with fibres. Therefore given information about fibres did not increase liking of the fibre rye breads. Finally, it can be concluded that elderlies would eat bread fortified with fibers and there were differences in liking of bread between elderlies and young. </p>
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Stevulova, Nadezda, Viola Hospodarova, Vojtech Vaclavik, Tomas Dvorsky i Tomas Danek. "Characterization of cement composites based on recycled cellulosic waste paper fibres". Open Engineering 8, nr 1 (10.11.2018): 363–67. http://dx.doi.org/10.1515/eng-2018-0046.
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AbstractNowadays, there is paying an attention to the utilization of natural, renewable and biodegradable resources of raw materials of lignocellulosic character, residues from agricultural crops and wood processing as well as waste from papermaking industry in building composite materials preparing. Also recycled fibres coming from waste paper are considered as valuable material. The objective of this study is to utilize these recycled cellulosic fibres into cement composites and characterise their impact on resulting physical and mechanical properties of fresh and hardened cement composites. Manufactured cement composites contained 0.2%, 0.3% and 0.5% addition of cellulosic fibres. In fresh fibre cement mixtures reduction in workability with increasing amount of cellulose fibres was noticed. Density as well as compressive and flexural strength of 28 and 90 days hardened fibre cement composites was tested. Distribution of cellulosic fibres with 0.5% addition in hardened fibre cement composites was also observed. The results of density determination of 28 and 90 days hardened fibre cement composites showed reduction in their values related to weight lighter concretes. Compressive strengths of fibre cement composites have shown decreasing character with increasing added amount of cellulosic fibres into the mixture up to 0.5%. Maximal decrease in compressive strength values was observed in composites containing 0.5% of cellulosic fibres. However, obtained strength parameter values of hardened composites had satisfying results for their application in construction as non-load bearing building material.
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Sumithra, Murugesan, i Gayathri Murugan. "Extraction and characterization of natural fibres form Elettaria Cardamomum". Tekstilna industrija 69, nr 2 (2021): 30–33. http://dx.doi.org/10.5937/tekstind2102030s.
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Natural fibres are one of the good alternative sources for replacing synthetic fibres and reinforcing polymer matrices because of their eco-friendly nature. The present study was undertaken to investigate the fibres extract from Elettaria Cardamomum plant. The extracted Elettaria Cardamomum fibre was treated with NaOH for softening. Natural cellulose fibres extracted from Elettaria Cardamomum stems (ECS) have been characterized for their chemical composition and physical properties.The chemical composition of Elettaria Cardamomumstems (ECS) fi bres is, cellulose 60.44%, lignin 25.25%, wax 0.53%, ash 5.45%. Regarding physical properties of the fibres, single fibre strength was evaluated and the result was compared with cotton fibre and linen fibre.
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Sobczak, L., A. Limper, H. Keuter, K. Fischer i A. Haider. "Polypropylene-cellulose Innovative Compounding Technology". Polymers from Renewable Resources 3, nr 1 (luty 2012): 27–32. http://dx.doi.org/10.1177/204124791200300103.
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Lightweight construction and recyclability are essential factors when it comes to meeting environmental targets. Natural fibre-reinforced composites (NFCs) have an important role to play here. The density of natural fibre materials is up to 50% lower than that of the reinforcing fibres traditionally used for plastics, such as glass fibres, and as well as being fully recyclable the composites offer 100% thermal energy recovery.
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Števulova, Nadežda, Viola Hospodárova i Adriana Eštoková. "Study of Thermal Analysis of Selected Cellulose Fibres". GeoScience Engineering 62, nr 3 (1.12.2016): 18–21. http://dx.doi.org/10.1515/gse-2016-0020.
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Abstract This paper provides the investigation of thermal analysis of cellulose fibres which will be used into building materials as a partial filler replacement. Cellulosic fibres come from two various sources: bleached wood pulp and unbleached waste paper whereas these natural fibres have different cellulose contents and another manufacturing process. Natural fibres have been widely used as reinforcing fillers in composite materials in recent years. As a result, they are subjected to thermal degradation during composite processing. It is thus of practical significance to understand and predict the thermal decomposition process of natural fibres and the knowledge will help better design the composite process and estimate the influence on composite properties by the thermal decomposition of natural fibres. The results obtained from the thermal analysis of cellulosic fibres showed differences in their thermal decomposition and also differences in the weight loss due to their chemo-mechanical treatment, the presence of impurities and CaCO3 originating from filler in paper making.
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Manian, Avinash Pradip, Barbara Paul, Helene Lanter, Thomas Bechtold i Tung Pham. "Cellulose Fibre Degradation in Cellulose/Steel Hybrid Geotextiles under Outdoor Weathering Conditions". Polymers 14, nr 19 (5.10.2022): 4179. http://dx.doi.org/10.3390/polym14194179.
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Risks from rockfall and land sliding can be controlled by high-tensile steel nets and meshes which stabilise critical areas. In many cases, a recultivation of the land is also desired. However, high-tensile steel meshes alone are not always sufficient, depending on the location and the inclination of the stabilised slope, to achieve rapid greening. Cellulose fibres exhibit high water binding capacity which supports plant growth. In this work, a hybrid structure consisting of a nonwoven cellulose fibre web and a steel mesh was produced and tested under outdoor conditions over a period of 61 weeks. The cellulose fibres are intended to support plant growth and soil fixation, and thus the biodegradation of the structure is highly relevant, as these fibres will become part of the soil and must be biodegradable. The biodegradation of the cellulose fibres over the period of outdoor testing was monitored by microscopy and analytical methods. The enzymatic degradation of the cellulose fibres led to a reduction in the average degree of polymerisation and also a reduction in the moisture content, as polymer chain hydrolysis occurs more rapidly in the amorphous regions of the fibres. FTIR analysis and determination of carboxylic group content did not indicate substantial changes in the remaining parts of the cellulose fibre. Plant growth covered geotextiles almost completely during the period of testing, which demonstrated their good compatibility with the greening process. Over the total period of 61 weeks, the residual parts of the biodegradable cellulose web merged with the soil beneath and growing plants. This indicates the potential of such hybrid concepts to contribute a positive effect in greening barren and stony land, in addition to the stabilising function of the steel net.
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Ullrich, Julia, Martin Eisenreich, Yvonne Zimmermann, Dominik Mayer, Nina Koehne, Jacqueline F. Tschannett, Amalid Mahmud-Ali i Thomas Bechtold. "Piezo-Sensitive Fabrics from Carbon Black Containing Conductive Cellulose Fibres for Flexible Pressure Sensors". Materials 13, nr 22 (16.11.2020): 5150. http://dx.doi.org/10.3390/ma13225150.
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The design of flexible sensors which can be incorporated in textile structures is of decisive importance for the future development of wearables. In addition to their technical functionality, the materials chosen to construct the sensor should be nontoxic, affordable, and compatible with future recycling. Conductive fibres were produced by incorporation of carbon black into regenerated cellulose fibres. By incorporation of 23 wt.% and 27 wt.% carbon black, the surface resistance of the fibres reduced from 1.3 × 1010 Ω·cm for standard viscose fibres to 2.7 × 103 and 475 Ω·cm, respectively. Fibre tenacity reduced to 30–50% of a standard viscose; however, it was sufficient to allow processing of the material in standard textile operations. A fibre blend of the conductive viscose fibres with polyester fibres was used to produce a needle-punched nonwoven material with piezo-electric properties, which was used as a pressure sensor in the very low pressure range of 400–1000 Pa. The durability of the sensor was demonstrated in repetitive load/relaxation cycles. As a regenerated cellulose fibre, the carbon-black-incorporated cellulose fibre is compatible with standard textile processing operations and, thus, will be of high interest as a functional element in future wearables.
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Syarif, M. A., F. Fahma i I. Sailah. "Bioplastic beads composite production based on cellulose acetate-starch blend: a literature study". IOP Conference Series: Earth and Environmental Science 1063, nr 1 (1.07.2022): 012015. http://dx.doi.org/10.1088/1755-1315/1063/1/012015.
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Abstract Cellulose and starch are two natural biological sources that have potential as bioplastic raw materials. Cellulose and starch show tremendous potential to reduce environmental pollution caused by conventional plastics. The compatibility between the cellulosic fibre matrices plays an important role in the properties of the resulting bioplastic. The modification of cellulose into cellulose acetate makes the resulting bioplastics have better mechanical properties. In addition, bioplastics can be composite with starch to have a stronger matrix. Cellulose-starch bio-composites have also been successfully produced. In this article, the focus on the formulation and characterization of cellulosic fibres and starch concerning their application in bioplastics will be discussed. Then, generalize the development and problems of bioplastics that are composite with starch to improve the mechanical properties of bioplastics.
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Nguyen, Vu Viet Linh. "Effects of the chemical treatment process with different agents on the morphologyand properties of banana fibres". Ministry of Science and Technology, Vietnam 65, nr 1 (25.01.2023): 44–48. http://dx.doi.org/10.31276/vjst.65(1).44-48.
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Banana fibre is one of the natural materials with high cellulose content that has been studied and applied in various fields such as composites, paper, filter bags... This study investigated and evaluated the morphology and properties of banana leaf fibres after being treated with agents such as water, NaOH, and H2O2 under dif-ferent conditions. The changes in morphology, size, and chemical composition of banana fibres were analysed by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) methods. The SEM results showed that the cellulose microfibres were separated from banana fibres after treating with these chemical agents, and the average diameter obtained 34.3 μm. After treatment, the FTIR spectra of the samples showed that these agents removed lignin, hemicellulose and non-cellulose components in the fibres. After treat-ment with NaOH and H2O2, lignin, hemicellulose and non-cellulose components were mostly removed from the fiber. The remaining lignin can be used as a binder for cellulose film based on banana leaves fibres.
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Cordin, Michael, i Thomas Bechtold. "Physical properties of lyocell-reinforced polypropylene composites from intermingled fibre with varying fibre volume fractions". Journal of Thermoplastic Composite Materials 31, nr 8 (19.10.2017): 1029–41. http://dx.doi.org/10.1177/0892705717734594.
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Polypropylene (PP)-cellulose fibre blends exhibit substantial potential for the production of high-performance textile fibre–reinforced composites. The production of reinforced parts from PP-cellulose composites through thermal shaping of intermingled fibre blends is a strategy to form parts which exhibit superior mechanical properties. In this study, the use of intermingled fibre slivers with different ratios of lyocell fibres (CLY) and PP fibres as raw materials for thermally formed composites was investigated. Such a concept will maximize the interface between the reinforcement fibres and polymer matrix. The cellulose fibres remain oriented along the direction in which the drawing process was performed, which forms the basis for tailored fibre placement in technical production. Because of good surface contact between the cellulose fibre surface and PP matrix, no special coupling agents were required to improve the interfacial adhesion between the two different polymers. The share of CLY and PP fibres in the composite varied from 50% w/w CLY content, up to 70% w/w CLY. Besides analysis of the mechanical properties, such as tensile strength and E-modulus, attention was directed towards moisture sorption of the composites. The rate of sorption and amount of water bound in the composite were found to be dependent on the cellulose fibre content. Composites with a higher CLY content exhibited a more rapid and higher moisture uptake. In water saturated state, the ultimate tensile strength of composites reduced from 160 MPa to 90 MPa, which is an indicator for a reduced adhesion between the CLY surface and PP matrix. The results indicate the potential of the intermingled fibre concept blend for the efficient manufacturing of composite parts.
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Shahriarinour, Mahdi, Mohd Noor Abdul Wahab, Shuhaimi Mustafa, Rosfarizan Mohamad i Arbakariya B. Ariff. "Effect of various pretreatments of oil palm empty fruit bunch fibres for subsequent use as substrate on the performance of cellulase production by Aspergillus terreus". BioResources 6, nr 1 (7.12.2010): 291–307. http://dx.doi.org/10.15376/biores.6.1.291-307.
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The possibility of using treated oil palm empty fruit bunch (OPEFB) fibres as substrate for cellulase production by Aspergillus terreus was studied using shaking flask fermentation. The effect of different chemical pretreatments, i.e. formic acid, acetic acid, propylamine, phosphoric acid, and n-butylamine, on the suitability of OPEFB fibres as fermentation substrate was investigated. The findings revealed that pretreatment with these chemicals significantly (P<0.05) increased the cellulose and reduced the lignin contents prior to enzymatic hydrolysis. However, fermentation using OPEFB fibres pretreated with phosphoric acid gave the highest cellulase production, which was related to high cellulose content. Further improvement in cellulase production was obtained when the chemically pretreated OPEFB fibres were subsequently treated hydrothermally (autoclaved at 160oC for 10 min) and then biologically (using effective microorganisms). The final activity of the three main components of cellulase (FPase, CMCase, and β-glucosidase) obtained in fermentation by A. terreus using optimally treated OPEFB fibres was (0.77 U mL−1, 8.5 U mL-1, and 6.1 U mL-1), respectively. The production of all these three major components of cellulase using pretreated OPEFB fibres (i.e. chemical, hydrothermal, and biological) were about three times higher than those obtained from fermentation using untreated OPEFB fibres.
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Krmelová, V., M. Gavendová, J. Krmela, P. Skalková i E. Loksik. "Thermal and Mechanical Characterization of Drawn Polypropylene Fibres". IOP Conference Series: Materials Science and Engineering 1199, nr 1 (1.11.2021): 012029. http://dx.doi.org/10.1088/1757-899x/1199/1/012029.
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Abstract The main objective of this work was to investigate the effect of different cellulose (CEL) content and the draw ratio on the thermal and mechanical properties of drawn polypropylene (PP) fibres. The modification of PP fibres during their production can helps to prepare PP fibres with improved properties, guarantees new opportunities for the expansion of an assortment of PP fibres in the clothing and domestic textile industries. The modified PP/CEL fibres were prepared from PP pellets and PP/cellulose masterbatch via the melt spinning technique at 260 °C followed by drawing for various draw ratios in the company Chemosvit, Fibrochem a. s. (Svit, Slovakia). Differential scanning calorimetry (DSC) was used to evaluate the thermal properties of PP fibres. The mechanical properties (tenacity and elongation at break and modulus of elasticity) and low cycle loading of modified PP fibres were also studied. The obtained experimental results of drawn PP/CEL fibres were compared with neat PP fibre prepared under the same technological conditions. Cellulose had a minimal effect on the melting temperatures of fibres and increased of the PP crystallization temperatures in comparison with the neat drawn PP fibre. The limited decrease of mechanical properties of prepared fibres were observed, but the decreases do not influence on the fibres commercial use.
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Schmidt, Vivian Consuelo Reolon, i João Borges Laurindo. "Characterization of foams obtained from cassava starch, cellulose fibres and dolomitic limestone by a thermopressing process". Brazilian Archives of Biology and Technology 53, nr 1 (luty 2010): 185–92. http://dx.doi.org/10.1590/s1516-89132010000100023.
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Cassava starch, dolomitic limestone and eucalypt cellulose fibres were used to prepare foam trays that could be used to pack foodstuffs. The influence of the cellulose fibre concentration in the composite formulation was investigated using 5, 10, 15, 20, 30 and 40% of fibres. The results indicated that an increase in cellulose fibre concentration promoted a decrease in density and tensile strength of the foam samples. The tensile strength at break for foam trays containing 5% of cellulose fibres was 3.03MPa, whilst the commercial trays of expanded polystyrene used to pack foods in supermarkets presented a tensile strength of 1.49 MPa. The elongation at break of the foam trays obtained in this work varied slightly with increase in cellulose fibre concentration, the values being about 20% lower than the elongation at break observed for commercial foam trays of expanded polystyrene. Thus, the materials developed in this work represented a possible alternative to the use of EPS foam trays for packing dry foods. The trays' properties need to be improved for their use with moist foods.
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Bengtsson, Andreas, Jenny Bengtsson, Carina Olsson, Maria Sedin, Kerstin Jedvert, Hans Theliander i Elisabeth Sjöholm. "Improved yield of carbon fibres from cellulose and kraft lignin". Holzforschung 72, nr 12 (19.12.2018): 1007–16. http://dx.doi.org/10.1515/hf-2018-0028.
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AbstractTo meet the demand for carbon-fibre-reinforced composites in lightweight applications, cost-efficient processing and new raw materials are sought for. Cellulose and kraft lignin are each interesting renewables for this purpose due to their high availability. The molecular order of cellulose is an excellent property, as is the high carbon content of lignin. By co-processing cellulose and lignin, the advantages of these macromolecules are synergistic for producing carbon fibre (CF) of commercial grade in high yields. CFs were prepared from precursor fibres (PFs) made from 70:30 blends of softwood kraft lignin (SW-KL) and cellulose by dry-jet wet spinning with the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([EMIm][OAc]) as a solvent. In focus was the impact of the molecular mass of lignin and the type of cellulose source on the CF yield and properties, while membrane-filtrated kraft lignin and cellulose from dissolving kraft pulp and fully bleached paper-grade SW-KP (kraft pulp) served as sources. Under the investigated conditions, the yield increased from around 22% for CF from neat cellulose to about 40% in the presence of lignin, irrespective of the type of SW-KL. The yield increment was also higher relative to the theoretical one for CF made from blends (69%) compared to those made from neat celluloses (48–51%). No difference in the mechanical properties of the produced CF was observed.
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Mokshina, Natalia, Oleg Gorshkov, Nadezda Ibragimova, Tatyana Chernova i Tatyana Gorshkova. "Cellulosic fibres of flax recruit both primary and secondary cell wall cellulose synthases during deposition of thick tertiary cell walls and in the course of graviresponse". Functional Plant Biology 44, nr 8 (2017): 820. http://dx.doi.org/10.1071/fp17105.
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Cellulose synthesising complex consists of cellulose synthase (CESA) subunits encoded by a multigene family; different sets of CESA genes are known to be expressed during primary and secondary cell wall formation. We examined the expression of LusCESAs in flax (Linum usitatissimum L.) cellulosic fibres at various stages of development and in the course of graviresponse by means of RNA-Seq and quantitative PCR. Transcripts for both primary and secondary cell wall-related CESAs were abundant in fibres depositing highly cellulosic tertiary cell walls. Gravistimulation of flax plants temporally increased the abundance of CESA transcripts, specifically in phloem fibres located at the pulling stem side. Construction of coexpression networks for LusCESAs revealed that both primary and secondary cell wall-related CESAs were involved in the joint coexpression group in fibres depositing tertiary cell walls, as distinct from other tissues, where these genes were within separate groups. The obtained data suggest that fibres depositing tertiary cell walls have a specific mechanism of cellulose biosynthesis and a specific way of its regulation.
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Raj, Gijo, Eric Balnois, Christophe Baley i Yves Grohens. "Role of Polysaccharides on Mechanical and Adhesion Properties of Flax Fibres in Flax/PLA Biocomposite". International Journal of Polymer Science 2011 (2011): 1–11. http://dx.doi.org/10.1155/2011/503940.
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The effect of alkali and enzymatic treatments on flax fibre morphology, mechanical, and adhesion properties was investigated. The multilength scale analysis allows for the correlation of the fibre's morphological changes induced by the treatments with mechanical properties to better explain the adherence properties between flax and PLA. The atomic force microscopy (AFM) images revealed the removal of primary layers, upon treatments, down to cellulose microfibrils present in the secondary layers. The variation in mechanical properties was found to be dependent, apart from the crystalline content, on interaction between cellulose microfibrils and encrusting polysaccharides, pectins and hemicelluloses, in the secondary layers. Finally, microbond tests between the modified fibres and PLA emphasize the important role of the outer fibre's surface on the overall composite properties. It was observed here that gentle treatments of the fibres, down to the oriented microfibrils, are favourable to a better adherence with a PLA drop. This paper highlights the important role of amorphous polymers, hemicellulose and pectin, in the optimisation of the adhesion and mechanical properties of flax fibres in the biocomposite.
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Hilman, A., T. Karo-karo, Azhari, H. Sakdiah, N. A. Salma i I. Pangestu. "Hydrolysis of alkaline treatment and characterization of cellulose fibrils from processing waste of bengkoang water-soluble polysaccharide". IOP Conference Series: Earth and Environmental Science 977, nr 1 (1.06.2022): 012087. http://dx.doi.org/10.1088/1755-1315/977/1/012087.
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Abstract Cellulose fibrils are insoluble dietary fibres in the processing waste of bengkoang water-soluble polysaccharides (WSP). The researcher has investigated the characterization of chemical and morphological properties of WSP bengkoang in previous studies. However, the processing waste of the insoluble dietary fibres from WSP bengkoang still needs to be studied. This research aim is to hydrolyze and characterize the cellulose fibrils from bengkoang water-soluble polysaccharides. The results showed that the crude fibres assisted with alkaline treatment would lead to the swollen thread and remove materials like soluble and insoluble lignin to become cellulose fibrils. The morphology of natural fibres has mixed with starch from the processing waste of bengkoang water-soluble polysaccharides. Meanwhile, the cellulose fibrils look clear with a dimension of around 10–14 μm. The FTIR graph shows a degradation in the quantum of linking materials allows in the fibres due to alkaline treatment. The raw fibres characteristic peak does not appear due to alkaline hydrolisis treatment. The peak between 1200 and 1300 cm-1 which decreases due to alkaline treatment is mainly responsible for the wax, lignin, pectin, and other impurities components. The color degree of cellulose fibrils were indicate due to the removal of other impurities and non-cellulosic components.
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Pinrat, S., P. Dittanet, A. Seubsai i P. Prapainainar. "Fabrication of Natural Rubber Latex Foam Composite Filled with Pineapple-leaf Cellulose Fibres". Journal of Physics: Conference Series 2175, nr 1 (1.01.2022): 012038. http://dx.doi.org/10.1088/1742-6596/2175/1/012038.
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Abstract Pineapple leaf (PL) is a renewable agriculture residue which are abundance in Thailand. In this paper, cellulose powder was extracted from PL. Celluloses are typically used as fillers for rubber reinforced composites due to their properties such as high mechanical properties, low cost, low density, and biodegradability. The aim of this study was to optimize the method to prepare natural rubber latex foam (NRLF) with different cellulose loadings from 0 to 7 phr by using Dunlop method. The different steps for adding celluloses in this study were adding in pre-vulcanization process and in foaming process were studied. The tensile properties, density, compression, and microstructural characterization were studied. Morphological and microstructural performed by using scanning electron microscopy (SEM). It was found that adding cellulose in pre-vulcanization step showed well distribution of cellulose while adding cellulose in foaming process showed the settle of cellulose at the bottom of the foam sample. The tensile strength and elongation at break decreased with increasing of cellulose content whereas modulus increased with increasing of cellulose content.
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Henriksson, Åsa, i Paul Gatenholm. "Controlled Assembly of Glucuronoxylans onto Cellulose Fibres". Holzforschung 55, nr 5 (19.09.2001): 494–502. http://dx.doi.org/10.1515/hf.2001.081.
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Summary In this study we have shown that cellulose fibres can be coated with regular micron-sized particles by controlling the assembly process of xylans on the cellulose surfaces. When cotton linters were exposed to a 5% water solution of xylan from birchwood at 110°C, 2 h, pH 8, the substrates showed an increase in weight of approximately 6.5%, and visualization by AFM revealed regular particles on the fibre surfaces. The surface modification process was optimized using an experimental design where time, temperature, and pH were varied. The experiments showed that the amount of xylan deposited on the fibres could be varied from 2% up to 20% depending on treatment conditions. The temperature and time were the most important parameters, while pH was not important in the investigated region. The morphology of the deposited xylan layer, as shown by SEM, was dependent on the amount of xylan on the fibre surfaces. At low yield the fibres were coated with a homogenous layer, while at higher yields (20%) regular particles of micron size were identified by AFM analysis. The mechanism of this assembly process of xylan on cellulose fibre surfaces is discussed.
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Möhl, Claudia, i Andreas Krombholz. "Impact Resistance Bio Compound". Materials Science Forum 825-826 (lipiec 2015): 1047–54. http://dx.doi.org/10.4028/www.scientific.net/msf.825-826.1047.
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Modified wood fibre reinforced polypropylene composites at a wood fibre content of 50 wt. % are prepared using different types of wood fibres (beech wood refiner fibre, mercerised beech wood refiner fibre, mercerised and bleached beech wood refiner fibre as well as beech wood chips, mercerised beech wood chips, mercerised and bleached beech wood chips) to improve the impact resistance of the final composite. Additionally a beech wood refiner fibre-PP composite as well as a beech wood chip-PP composite are mixed with regenerated cellulosic fibres (5 wt. % and 10 wt. %) to further enhance the impact resistance. To increase the interfacial adhesion with the matrix and to improve the dispersion of particles two different coupling agents with contents from 2 wt. % to 8 wt. % are tested with two wood plastic composites (WPC). One is made of beech wood refiner fibres and the other one is produced from beech wood chips.The present study investigated Charpy impact property of wood fibres reinforced polypropylene as a function of fibre modification, content of regenerated cellulosic fibres and coupling agent.From the results it is observed that beech wood refiner fibre-PP composites show better Charpy impact properties than beech wood chips-PP composites. Charpy impact resistance is improved by mixing regenerated cellulose fibres (RCF) and RCF-PP-granule with beech wood refiner fibres and chips. The maximum increase in impact resistance is two times for refiner fibres and 10 % RCF-PP-granule respectively three and a half times for chips and 10 % RCF-PP-granule. By adding coupling agent Charpy impact resistance is nearly doubled for all wood fibre-PP composites.
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Tonoli, Gustavo Henrique Denzin, M. N. Belgacem, G. Siqueira, J. Bras, Lourival M. Mendes, F. A. Rocco Lahr i H. Savastano Jr. "Processing Changes of Cement Based Composites Reinforced with Silane and Isocyanate Eucalyptus Modified Fibres". Key Engineering Materials 517 (czerwiec 2012): 437–49. http://dx.doi.org/10.4028/www.scientific.net/kem.517.437.
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Fibre-cement products had been widely used in the world due to their versatility as corrugated and flat roofing materials, cladding panels and water containers presented in large number of building and agriculture applications. The main reason for incorporating fibres into the cement matrix is to improve the toughness, tensile strength, and the cracking deformation characteristics of the resultant composite. One of the drawbacks associated with cellulose fibres in cement application is their dimensional instability in the presence of changing relative humidity. The objective of the present work is to evaluate the effect of surface treatment of eucalyptus cellulose pulp fibres on the processing and dimensional changes of fibre-cement composites. Surface modification of the cellulose pulps was performed with methacryloxypropyltri-methoxysilane (MPTS), aminopropyltri-ethoxysilane (APTS) and n-octadecyl isocyanate, an aliphatic isocyanate (AI), in an attempt to improve their dimensional instability into fibre-cement composites. X-ray photoelectron spectroscopy (XPS) showed the chemical changes occurred at the surface, and contact angle measurements showed the changes in the surface energy. MPTS-and AI-treated fibres presented lower hydrophilic character than untreated fibres, which led to lower water retention values (WRV). APTS increased the water retention value of the pulp and improved the capacity of hydrogen bonding of the fibres. MPTS-and AI-treated fibres led to low final water/cement ratios and reduced volume changes after pressing. MPTS-treated fibres decreased the water and dimensional instability of the fibre-cement composites, while the contrary occurred with APTS-modified and AI-modified fibres.These results are promising and contribute for new strategy to improve processing and stability of natural fibres-reinforced cement products.
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Maji, Somnath, Rajesh Mehrotra i Sandhya Mehrotra. "Extraction of high quality cellulose from the stem of Calotropis procera". South Asian Journal of Experimental Biology 3, nr 3 (15.08.2013): 113–18. http://dx.doi.org/10.38150/sajeb.3(3).p113-118.
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The stem of Calotropis procera (Vern. Aak) is a source of natural cellulosic bast fibres wherein the commercially valuable properties like cellulose content, fiber strength and fiber elongation are found to be intermediate between that of cotton and linen. Other than high tensile and abrasive strength, fibers from C. procera possess more weight per square meter than the cotton fibers. We have been trying to standardize protocol for isolation of high quality cellulose from Calotropis. We have compared the effects of alkali treatment and acid treatment on the yield and quality of cellulose fibers obtained. When the retted stems of C. procera were treated with 0.5N NaOH, the natural yield of cellulose fibers was approximately 6%. The efficiency of cellulose extraction was increased to 26% when the fibers were treated with 80% acetic acid and concentrated nitric acid (10:1). The percentage composition of cellulose was determined through infrared spectroscopy and acid detergent fiber method by refluxing. Acid treated fibers show higher percentage of cellulose content (85%) compared to the alkali treated method. The cellulose content in fibers obtained through acid treatment is comparable with that of cotton and better than linen. The acid treated method requires significantly less time compared to the alkali treated method. Since Calotropis is a wildly growing shrub in major parts of India, its use as a source of excellent cellulose fibers might have enormous economical implications.
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Paiva, M. C., Anissa El Gaied, R. Ben Cheikh i António M. Cunha. "Interfaces in Alfa Fibre-Polypropylene Matrix Composites". Materials Science Forum 587-588 (czerwiec 2008): 227–31. http://dx.doi.org/10.4028/www.scientific.net/msf.587-588.227.
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Model composites with Polypropylene (PP) as matrix and alfa fibres (cellulose-based fibres obtained from the esparto grass of the subsaarian dry regions of Tunisia) were prepared for fibre/matrix interfacial characterization studies. The matrices tested were PP and PP combined with PP modified with maleic anhydride (PP-g-MA). The surface of the alfa fibres was treated by air plasma treatment. The adhesion between the untreated and treated fibres and both matrices was studied using the fragmentation test method. Composites with 10% weight of fibres were prepared by melt extrusion and injection moulding, and the specimens obtained tested for tensile properties. The fracture surfaces of the composites, obtained at low temperature, were observed by scanning electron microscopy. The presence of a small concentration of maleic anhydride grafted to the polymer matrix was found to be of the utmost importance for the establishment of a good fibre/matrix interface. The air plasma treatment had a cleaning effect of the fibre’s surface.
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Šutka, Anna, Silvija Kukle, Janis Gravitis i Laima Grave. "Characterization of Cellulose Microfibrils Obtained from Hemp". Conference Papers in Materials Science 2013 (10.12.2013): 1–5. http://dx.doi.org/10.1155/2013/171867.
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Microfibrillated cellulose was extracted from hemp fibres using steam explosion pretreatment and high-intensity ultrasonic treatment (HIUS). The acquired results after steam explosion treatment and water and alkali treatments are discussed and interpreted by Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) was used to examine the microstructure of hemp fibres before and after each treatment. A fibre size analyser was used to analyse the dimensions of the untreated and treated cellulose fibrils. SEM observations show that the sizes of the different treated fibrils have a diameter range of several micrometres, but after HIUS treatment fibres are separate from microfibrils, nanofibres, and their agglomerates.
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Soatthiyanon, Niphaphun, i Alan Crosky. "Characterisation of Elementary Kenaf Fibres Extracted Using HNO3 and H2O2/CH3COOH". Fibers 10, nr 8 (25.07.2022): 63. http://dx.doi.org/10.3390/fib10080063.
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In this study, elementary kenaf fibres were separated from fibre bundles using two different treatments. The first involved treating with nitric acid (HNO3) while the second used a mixture of hydrogen peroxide (H2O2) and acetic acid (CH3COOH). Both treatments were successful in isolating the elementary fibres but the H2O2/CH3COOH gave a better fibre yield and required a shorter treatment time. The fibres treated with HNO3 had an average length of 0.2 mm, an aspect ratio of 15 and a defect density of 21 defects per mm. In contrast, the H2O2/CH3COOH treated fibres had a length of 2.3 mm, an aspect ratio of 179 and a defect density of 14 defects per mm. Both treatments removed lignin, pectin, and waxes. They also increased cellulose crystallinity in the fibres, especially for HNO3 treatment. However, they resulted in some oxidation of cellulose. The H2O2/CH3COOH treatment gave a substantial improvement in the thermal stability of the fibres while a marked decrease was observed for the HNO3 treatment.
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Chang, Sooyoung, Jaedeok Seo, Seokbin Hong, Duck-Gyu Lee i Wonjung Kim. "Dynamics of liquid imbibition through paper with intra-fibre pores". Journal of Fluid Mechanics 845 (20.04.2018): 36–50. http://dx.doi.org/10.1017/jfm.2018.235.
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We present a combined experimental and theoretical investigation of the dynamics of liquid imbibition through paper. The Washburn equation is widely used to describe the dynamics of capillary flow through paper, but this classical model has limited accuracy, which often makes it difficult to use in developing analytic systems such as paper-based microfluidic devices. We here report that the internal cavity of the cellulose fibres composing paper is significantly responsible for the limited accuracy of the Washburn equation. Our experiments demonstrated that liquid can be absorbed in the internal cavity of the cellulose fibres as well as in the inter-fibre pores formed by the fibre network. We developed a mathematical model for liquid imbibition by considering the flow through the intra-fibre pores based on experimental measurements of the intra-structure of cellulose fibres. The model markedly improves the prediction of the liquid absorption length, compared with the results of the Washburn equation, thus revealing the physics behind the limits of the Washburn equation. This study suggests that the accurate description of capillary imbibition through paper require parameters characterizing the internal pores of the cellulose fibres comprising the paper. Our results not only provide a new insight into porous media flows with different sized pores, but also provide a theoretical background for flow control in paper-based microfluidic systems.
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Wallwork, J. A. "Dyeing Cellulose Acetate Fibres". Journal of the Society of Dyers and Colourists 51, nr 12 (22.10.2008): 415–16. http://dx.doi.org/10.1111/j.1478-4408.1935.tb01853.x.
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Melle, Jürgen, Micheal Mooz i Frank Meister. "Nanoparticle Modified Cellulose Fibres". Macromolecular Symposia 244, nr 1 (grudzień 2006): 166–74. http://dx.doi.org/10.1002/masy.200651215.
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Degenstein, L. M., D. King, L. Lawson, W. Chute i P. I. Dolez. "Novel lyocell fibre from Alberta-grown hemp". IOP Conference Series: Materials Science and Engineering 1266, nr 1 (1.01.2023): 012018. http://dx.doi.org/10.1088/1757-899x/1266/1/012018.
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Abstract Lyocell is a man-made, regenerated cellulosic fibre developed through cellulose dissolution in non-derivative solvents. Hemp offers a preferential source of cellulose for lyocell production as it is considered an environmentally friendly agricultural crop, requiring less water, fertilizers, pesticides, and herbicides than other crops and sequesters carbon dioxide (CO2) from the atmosphere. There are currently no Canadian sources of domestically manufactured lyocell filament or staple fibres. Our goal is to manufacture 100% lyocell fibre and to demonstrate techniques for pulping and solution-spinning hemp-based lyocell fibre. Utilizing both the bast and hurd of the hemp plant allows for the creation of many different fibre densities with varying properties while contributing to whole plant utilization and Canadian industry creation and expansion.
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Lindström, Tom, i Gunborg Glad-Nordmark. "Novel bulking technologies for cellulose fibres". Nordic Pulp & Paper Research Journal 37, nr 1 (2.02.2022): 25–41. http://dx.doi.org/10.1515/npprj-2021-0065.
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Abstract This paper deals with the details of preparation of three principal routes for bulking of cellulose fibres. One route is dry cross-linking/hornification using aluminium ions and other salts followed by drying/curing. The mechanisms of these reactions still remain unknown. A second route is physical grafting of fibres using carboxymethylcellulose and bringing the acidic groups into their aluminium form before forming a sheet of paper/board. Hence, curing is not necessary, and this constitutes a unique wet bulking methodology. The mechanism behind this method is believed to be an increase in the surface friction of fibres, when the electrostatic double layer is shielded together with electrostatic cross-linking with aluminium ions. The higher friction between fibres partly prevents the sheet consolidation during drying. A third route is physical grafting of fibres using carboxymethyl cellulose and ion-exchanging the acidic groups with aluminium salts before drying and curing of the fibres. A most interesting factor is that all the thermal treatment methods do not form fibre nodules due to interfibre crosslinking during the heat treatment, a commonly observed phenomena when dealing with chemical crosslinking of fibres. All routes investigated are water-based and should be fairly simple to implement in commercial operations. An inherent advantage is that the bulking is associated with lower water retention values, which should be advantageous for a higher solids content after pressing and, hence, beneficial for paper machine productivity. Bulking is, however, also associated with a loss in bond strength, which in most cases must be alleviated using various additives such as starches and microfibrillated cellulose and it has also been demonstrated in the project how the strength properties (such as z-strength) could be restored at a higher bulk.
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Lorenz, Marcel, Stefan Sattler, Mehedi Reza, Alexander Bismarck i Eero Kontturi. "Cellulose nanocrystals by acid vapour: towards more effortless isolation of cellulose nanocrystals". Faraday Discussions 202 (2017): 315–30. http://dx.doi.org/10.1039/c7fd00053g.
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Cellulose nanocrystals (CNCs) are topical in materials science but their full potential is yet to be fulfilled because of bottlenecks in the production: the process consumes huge amounts of water, recycling the strong acid catalyst is difficult, and purification steps are cumbersome, particularly with lengthy dialysis. Production of CNCs with HCl vapour overcomes many of these difficulties but the dispersion of CNCs from the already hydrolysed fibre matrix is a formidable challenge. This study is a fundamental effort to explore very basic means to facilitate CNC dispersion from cotton linter fibres (filter paper), hydrolysed to levelling off degree of polymerization by HCl vapour. The introduction of carboxylic groups on the cellulose crystal surface proved the most efficient method to alleviate dispersion with good yields (ca. 50%) and a provisional possibility to tune the CNC length. By contrast, attempts to directly disperse untreated hydrolysed fibres in various organic solvents and aqueous surfactant solutions were unsuccessful. The results showed that hydrolysis of native cellulose fibres by HCl vapour is indeed a viable method for producing CNCs but it has more potential as a pre-treatment step rather than a full-fledged process on its own.
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Thomas, L. H., C. M. Altaner i M. C. Jarvis. "Identifying multiple forms of lateral disorder in cellulose fibres". Journal of Applied Crystallography 46, nr 4 (22.06.2013): 972–79. http://dx.doi.org/10.1107/s002188981301056x.
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Many strong biological materials exist in the form of fibres that are partially crystalline but contain a substantial proportion of disordered domains, which contribute to the mechanical performance but result in broadening of the reflections in the diffraction patterns of such materials and make structure determination difficult. Where multiple forms of disorder are simultaneously present, many of the accepted ways of modelling the influence of disorder on a fibre diffraction pattern are inapplicable. Lateral disorder in cellulose fibrils of flax fibres was characterized by a multi-step approach. First, a scattering component derived from domains less uniformly oriented than the rest was isolated. A second scattering component giving rise to asymmetry in the radial profiles of the equatorial reflections was then quantified and subtracted. This component was associated with domains that could be related to the crystalline cellulose lattice, but with more variable and, on average, wider equatorial d spacings. A further partially oriented component with highly disordered lateral d spacings unrelated to any of the cellulose lattice dimensions was identified. This component may be derived from non-cellulosic polysaccharides. The remaining broadening was then separated into a contribution from disorder within the crystalline lattice, including known disorder in hydrogen bonding, and a Scherrer contribution from the microfibril diameter. The methods described are likely to find applications in the study of both natural and synthetic polymer fibres in which mechanical properties are influenced by disorder.
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Kumpikaitė, Eglė, Sandra Varnaitė-Žuravliova, Indrė Tautkutė-Stankuvienė i Ginta Laureckienė. "Comparison of Mechanical and End-Use Properties of Grey and Dyed Cellulose and Cellulose/Protein Woven Fabrics". Materials 14, nr 11 (26.05.2021): 2860. http://dx.doi.org/10.3390/ma14112860.
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The behaviour of textile products made from different fibres during finishing has been investigated by many scientists, but these investigations have usually been performed with cotton or synthetic yarns and fabrics. However, the properties of raw materials such as linen and hemp (other cellulose fibres) and linen/silk (cellulose/protein fibres) have rarely been investigated. The aim of the study was to investigate and compare the mechanical (breaking force and elongation at break) and end-use (colour fastness to artificial light, area density, and abrasion resistance) properties of cellulose and cellulose/protein woven fabrics. For all fabrics, ΔE was smaller than three, which is generally imperceptible to the human eye. Flax demonstrated the best dyeability, and hemp demonstrated the poorest dyeability, comparing all the tested fabrics. The colour properties of fabrics were greatly influenced by the washing procedure, and even different fabric components of different weaves lost their colours in different ways. Flax fibres were more crystalline than hemp, and those fibres were more amorphous, which decreased the crystallinity index of flax in flax/silk blended fabric. Unwashed flax fabric was more resistant to artificial light than flax/silk or hemp fabrics. Finishing had a great influence on the abrasion resistance of fabrics. The yarn fibre composition and the finishing process for fabrics both influenced the mechanical (breaking force and elongation at break) and end-use (area density and abrasion resistance) properties of grey and finished fabrics woven from yarns made of different fibres.
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Pöhler, Tiina, Petri Widsten i Tuula Hakkarainen. "Improved Fire Retardancy of Cellulose Fibres via Deposition of Nitrogen-Modified Biopolyphenols". Molecules 27, nr 12 (10.06.2022): 3741. http://dx.doi.org/10.3390/molecules27123741.
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Driven by concerns over the health and environmental impacts of currently used fire retardants (FRs), recent years have seen strong demand for alternative safer and sustainable bio-based FRs. In this paper, we evaluated the potential of nitrogen-modified biopolyphenols as FRs for cellulosic natural fibres that could be used in low-density cellulose insulations. We describe the preparation and characterisation of nitrogen-modified lignin and tannin containing over 10% nitrogen as well as the treatment of cellulose pulp fibres with combinations of lignin or tannin and adsorption-enhancing retention aids. Combining lignin or tannin with a mixture of commercial bio-based flocculant (cationised tannin) and anionic retention chemical allowed for a nearly fourfold increase in lignin adsorption onto cellulosic pulp. The nitrogen-modified biopolyphenols showed significant improvement in heat release parameters in micro-scale combustion calorimetry (MCC) testing compared with their unmodified counterparts. Moreover, the adsorption of nitrogen-modified lignin or tannin onto cellulose fibres decreased the maximum heat release rate and total heat release compared with cellulose reference by 15–23%. A further positive finding was that the temperature at the peak heat release rate did not change. These results show the potential of nitrogen-modified biopolyphenols to improve fire-retarding properties of cellulosic products.
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Ilyas, R. A., S. M. Sapuan, M. R. Ishak i E. S. Zainudin. "Effect of delignification on the physical, thermal, chemical, and structural properties of sugar palm fibre". BioResources 12, nr 4 (4.10.2017): 8734–54. http://dx.doi.org/10.15376/biores.12.4.8734-8754.
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Eco-friendly composites can be prepared by substituting man-made synthetic fibres with various types of cellulosic fibres. Sugar palm-derived nanocrystalline cellulose is a potential substitute. The most important factor in determining a good nanofiller reinforcement agent that can be used in composites is the character of the nanofiller itself, which is affected during a preliminary treatment. Thus, to gain better nanofiller properties, the delignification (NaClO2 and CH3COOH) and mercerization (NaOH) treatments must be optimized. The main objective of this study was to identify the effects of the delignification and mercerization treatments on sugar palm fibre (SPF). In addition, the characteristics of the SPF for the preparation of the hydrolysis treatment to produce nanocrystalline cellulose (NCC) for reinforcement in polymer composites were examined. Sugar palm cellulose (SPC) was extracted from the SPF, and its structural composition, thermal stability, functional groups, and degree of crystallinity were determined via field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD), respectively. The density, moisture content, chemical composition, and structure of the SPC were also analysed.
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Mazian, Brahim, Anne Bergeret, Jean-Charles Benezet i Luc Malhautier. "A Comparative Study of the Effect of Field Retting Time on the Properties of Hemp Fibres Harvested at Different Growth Stages". Fibers 7, nr 12 (7.12.2019): 108. http://dx.doi.org/10.3390/fib7120108.
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In this study, the comparison of field retting of hemp fibres harvested at different growth stages (beginning and end of flowering, seed maturity) was studied. Regardless of the harvest period, identical evolution of the fibres’ properties was observed during retting. The main difference is the kinetics of this transformation, which depend on weather conditions and the initial state of the fibres after harvesting. Retting leads to a change in colour of the stems and fibres, an increase of the cellulose fraction and a gradual improvement of the fibres’ thermal stability, in relation with a decrease in the non-cellulosic materials. This process induces fibre bundle separation into elementary fibres. A long period (5 weeks) is required for getting the highest mechanical properties of fibres harvested at the beginning and the end of flowering. However, the retting of fibres harvested at seed maturity has to be performed in a short period (1 week) in order to avoid over-retting treatment. If the fibres are over-retted, their quality decreases in terms of structure and mechanical properties.
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Liitiä, Tiina, Sirkka L. Maunu i Bo Hortling. "Solid State NMR Studies on Inhomogeneous Structure of Fibre Wall in Kraft Pulp". Holzforschung 55, nr 5 (19.09.2001): 503–10. http://dx.doi.org/10.1515/hf.2001.082.
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Summary Solid state NMR spectroscopy was used to analyse the inhomogeneous structure of kraft fibre. Primary fines, isolated from the original kraft pulp, and secondary fines, isolated after refining, were compared with the corresponding long fibres. To fractionate fibre wall surface material, the kraft pulp was refined in stages. After each stage, the secondary fines and long fibres were separated and the long fibres refined again to peel off the surface material. It was found that the crystallinity of cellulose is lower in fines compared with the corresponding long fibres. When the fines fractions were compared with each other, the cellulose crystallinity was observed to increase towards the inner parts of the fibre surface. A very clear gradient was also seen in the amount of extractives, which was highest in the primary fines rich in ray cells. The contents of lignin and some hemicelluloses, mainly xylan and glucomannan, were also higher in fines. Residual lignin isolated from the fines was found to be slightly more condensed than residual lignin from long fibres.
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Liitiä, T., S. L. Maunu i B. Hortling. "Solid State NMR Studies on Cellulose Crystallinity in Fines and Bulk Fibres Separated from Refined Kraft Pulp". Holzforschung 54, nr 6 (25.10.2000): 618–24. http://dx.doi.org/10.1515/hf.2000.104.
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Summary Solid state NMR spectroscopy has been used in this work to investigate crystallinity of cellulose in spruce wood before and after kraft pulping and TCF bleaching. Effects of refining of the spruce kraft pulp in water and in weak alkali have been studied by determination of the crystallinity of isolated fines and corresponding bulk fibres in order to find out whether the crystallinity in the fibre surface material and inside the fibre wall differ from each other. Also the possible effect of enzymatic endo-1,4-β-galactanase treatment on the crystallinity of some refined pulps has been investigated. It was found that the Iα crystalline form of cellulose predominates over the Iβ form in native spruce and vice versa in all the pulps studied. In pulping part of the cellulose Iα is converted to the more stable Iβ form mainly by heat. Any measurable changes in the degree of crystallinity or in the relative proportions of different crystalline forms of cellulose could not be seen in pulps after refining, TCF-bleaching or galactanase treatment. However, the degree of crystallinity was found to be considerably lower in the fines compared to the corresponding bulk fibres. Therefore it is suggested that the cellulose crystallinity is lower or the size of crystallites smaller on the fibre surface than inside the fibre wall. Slightly higher contents of lignin and hemicelluloses, mainly xylan and mannan, were also found in the fines compared to the bulk fibres.
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Määttänen, Marjo, Maria Gunnarsson, Helena Wedin, Sara Stibing, Carina Olsson, Tobias Köhnke, Sari Asikainen, Marianna Vehviläinen i Ali Harlin. "Pre-treatments of pre-consumer cotton-based textile waste for production of textile fibres in the cold NaOH(aq) and cellulose carbamate processes". Cellulose 28, nr 6 (2.03.2021): 3869–86. http://dx.doi.org/10.1007/s10570-021-03753-6.
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AbstractRecycling of textiles is of importance due to the large amount of waste generated from the increasing consumption and use worldwide. Cotton-rich pre-consumer textiles are considered as potential raw material for production of man-made regenerated fibres, but demands purification from the blends with synthetic fibres as well as the dyes and finishing chemicals. In this study we explore the use of different pre-treatments of pre-consumer textiles to meet specific parameters for production of fibres in the cold NaOH(aq) or cellulose carbamate process. The pre-treatments consisted of different bleaching sequences and were performed on both uncoloured and coloured pre-consumer textiles. For the uncoloured textile, degree of polymerisation and amount of inorganic content was efficiently reduced making the material suitable for both the cold NaOH(aq) and the cellulose carbamate process. In case of the coloured textile, the pre-treatments were able to remove the dye and decrease the inorganic content as well as reduce the degree of polymerisation but only sufficiently enough for production of fibres in the cellulose carbamate process. The work was able to prove a fibre-to-fibre concept while further optimisation of the regeneration steps is expected to improve the mechanical properties of the produced fibres in future studies.
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Sable, Inese, Uldis Grinfelds, Laura Vikele, Linda Rozenberga, Dagnija Lazdina, Martins Zeps i Aris Jansons. "Chemical composition and fiber properties of fast-growing species in Latvia and its potential for forest bioindustry". Forestry Studies 66, nr 1 (1.06.2017): 27–32. http://dx.doi.org/10.1515/fsmu-2017-0004.
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AbstractBioenergy, including energy from wood, currently provides about 9–13% of the total global energy supply. Every fibre of fast-growing wood has a value for its potential use as a material in both pulp and paper and wood chemical industries. The aim of this study was to assess the chemical composition and fibre’s properties of fast-growing species in Latvia – aspen, hybrid aspen, lodgepole pine, poplar and willow. Results showed a variation of cellulose, lignin, extractives and ash contents among the species. Kraft pulp yield and amount of residual lignin were measured and properties of pulp fibres determined. Form factor and fine content in pulp were measured. Poplar and aspen wood had the highest content of cellulose, while lodgepole pine had the highest lignin content in wood and the longest kraft pulp fibres. Willow had 20% of fines in pulp. Individual results suggest the most suitable application of each species.
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Müssig, J., i N. Graupner. "Test Methods for Fibre/Matrix Adhesion in Cellulose Fibre-Reinforced Thermoplastic Composite Materials: A Critical Review". Reviews of Adhesion and Adhesives 8, nr 2 (30.06.2020): 68–129. http://dx.doi.org/10.7569/raa.2020.097306.
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Due to the increasing discussion about sustainable and CO2-reduced materials, the demand for cellulose-based fibres as a reinforcing component in thermoplastic composites has increased considerably. Knowledge about the possibilities of modifying fibres for improved adhesion to the plastic matrix is essential in this context. The fibre/matrix adhesion in cellulose fibre-reinforced polymers is of considerable importance for the design of composite materials. Unfortunately, there are no standards for many essential methods to determine fibre/matrix adhesion. In this review article, various methods for measuring the interfacial shear strength between fibres and matrix, as an indirect characterisation of adhesion, are presented. Additionally, a brief overview of different methods for surface modification of cellulose fibres to improve the adhesion to a thermoplastic matrix is given. This review focuses on the fact that the parameters for the production of test specimens as well as the test method itself can vary considerably from study to study. Because of this, the comparison of data from different publications is not always possible. Therefore, in this article, the main influencing factors and differences in the methods are presented and discussed. Based on a systematic review and a clear description and discussion of the methods, the reader is given a broad basis for a better understanding of characteristic values for fibre/matrix adhesion.
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Mburu, Ann Wairimu, Josphat Igadwa Mwasiagi i Joseph Kinyanjui Muiruri. "Influence of gin trash bacteria broth treatment on cotton fibres". Research Journal of Textile and Apparel 24, nr 3 (26.06.2020): 267–80. http://dx.doi.org/10.1108/rjta-10-2019-0051.
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Purpose Bacterial exopolysaccharides (eps) have fascinating chemical compositions, properties and structures which could be used in the modification of natural fibres. Bacterial eps have therefore been used to modify plant cellulose fibre surface and impart desired properties. The purpose of this paper is therefore to investigate the influence of gin trash cultured bacteria eps on the physical and structural properties of cotton fibres. Design/methodology/approach Gin trash soil sample was collected from a ginnery in Kenya, and physiochemical and microbial characterization was done. The soil sample was then fermented for 24 h before being used to treat raw cotton fibres at varied conditions of temperature, pH and treatment time periods. Physical and structural properties of the treated fibres were then determined using USTER HVI-1000 M700, Fourier transform infrared, scanning electron microscope (SEM) and X-ray diffraction (XRD) and compared with those of the raw fibres. Findings The bacteria broth treated fibres were found to have increased in strength, spinning consistency index, elongation and fineness by 25.44, 24.30, 11.70 and 3.60%, respectively. The variations were attributed to interactions of bacterial eps with cotton cellulose through hydrogen bonding. SEM and XRD analysis revealed an increase in fibre surface roughness and crystallinity, respectively. Originality/value Bacterial eps have been used to modify plant cellulose fibre surface and impart desired properties. Eps producing bacteria have been isolated from different habitats such as saline water, soil samples, food wastes and petroleum-contaminated soil. To the best of the authors’ knowledge, bacterial eps cultured from gin trash soil sample for modification of cotton fibres have however not been previously done, hence the originality of the current study.
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Larsson, P. A., i L. Wågberg. "Towards natural-fibre-based thermoplastic films produced by conventional papermaking". Green Chemistry 18, nr 11 (2016): 3324–33. http://dx.doi.org/10.1039/c5gc03068d.
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Strong and ductile barrier materials based on cellulose are predicted to be of great importance in a sustainable society. Such materials can be achieved by partial conversion of the cellulose of wood fibres to dialcohol cellulose. The chemical modification does not compromise the macroscopic fibre structure and still allows for rapid processing by conventional papermaking.
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Panthapulakkal, S., i M. Sain. "Preparation and Characterization of Cellulose Nanofibril Films from Wood Fibre and Their Thermoplastic Polycarbonate Composites". International Journal of Polymer Science 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/381342.
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The aim of this study was to develop cellulose-nanofibril-film-reinforced polycarbonate composites by compression molding. Nano fibres were prepared from wood pulp fibres by mechanical defibrillation, and diameter distribution of the fibres produced was in the range of 1–100 nm. Nanofibre films were prepared from the nanofibre suspensions and were characterized in terms of strength properties, crystallinity, and thermal properties. Strength and modulus of the nano fibre films prepared were 240 MPa and 11 GPa, respectively. Thermal properties of the sheets demonstrated the suitability of processing fibre sheets at high temperature. Tensile properties of the films subjected to composite-processing conditions demonstrated the thermal stability of the fibre films during the compression molding process. Nanocomposites of different fibre loads were prepared by press-molding nano fibre sheets with different thickness in between polycarbonate sheet at 205°C under pressure. The tensile modulus and strength of the polycarbonate increased with the incorporation of the fibres. The strength of the thermoplastic increased 24% with 10% of the fibres and is increased up to 30% with 18% of the fibres. Tensile modulus of the polycarbonate demonstrated significant enhancement (about 100%).
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Ardanuy, Mònica, Marcelo Antunes i Jose Ignacio Velasco. "Preparation and Characterization of Cellulosic Fibre-Reinforced Polypropylene Foams". Advanced Materials Research 123-125 (sierpień 2010): 1183–86. http://dx.doi.org/10.4028/www.scientific.net/amr.123-125.1183.
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The preparation and characterization of cellulosic fibre-reinforced polypropylene composite foams is presented. The cellulose fibres were isolated from a barley straw obtained from local sources. They were compounded with the polymer in the melt state to obtain composites with nominal concentrations of 10 and 20% by weight. After compression-moulding the composite samples were foamed in a high-pressure batch-process employing CO2 as foaming agent. The effects of the fibre loading on the basics characteristics of the foams was investigated.
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Fahlén, Jesper, i Lennart Salmén. "Ultrastructural changes in a holocellulose pulp revealed by enzymes, thermoporosimetry and atomic force microscopy". Holzforschung 59, nr 6 (1.11.2005): 589–97. http://dx.doi.org/10.1515/hf.2005.096.
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Abstract To increase our knowledge of the ultrastructure within softwood fibres, enzymatic treatment, thermoporosimetry, light microscopy, and atomic force microscopy with image analysis were used to investigate the structure of holocellulose softwood pulp fibres. The size of the average cellulose fibril aggregates and the width of pore and matrix lamellae were found to be uniform across the secondary cell-wall layer in the transverse direction of the wood fibre wall. In holocellulose, these dimensions were very similar to those in the native wood, whereas in kraft pulp the cellulose fibril aggregates were larger and the pore and matrix lamellae broader. These differences between holocellulose and kraft pulp fibres suggest that a high temperature is needed for cellulose fibril aggregation to occur. Neither refining nor drying of the holocellulose pulp changed the cellulose fibril aggregate size. Upon drying and enzymatic treatment, a small decrease in the pore and matrix lamella width was evident throughout the fibre wall. This indicated not only uniform distribution of pores throughout the fibre wall, but also enzymatic accessibility to the entire fibre wall. The holocellulose pulp had a somewhat larger pore volume than the kraft pulp. Refining of the holocellulose pulp led to pore closure, probably due to increased mobility of the fibre wall. The enzymatic treatment revealed that during hydrolysis of one hemicellulose, part of the other was also dissolved, indicating that the two hemicelluloses are to some extent linked to each other in the structure.
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Md. Shadiqul Islam, Mst. Ayesha Akther Zaman, Kamrun Nahar i Sharif Md. Al-Reza. "Effect of retting methods on molecular weight of Agave atroverance fibers". International Journal of Science and Research Archive 8, nr 1 (30.01.2023): 038–42. http://dx.doi.org/10.30574/ijsra.2023.8.1.0325.
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This study was undertaken to investigate the effect of retting method on the molecular weight of different portion of the Agave atroverance fiber (top, middle and bottom) extracted by different retting techniques. The raw fibers from Agave atroverance plant were retted by biological and chemical (degumming) retting methods. In biological retting method both the stagnant and boil water were utilized and in chemical retting method, the extracted fibres were treated with the 5% NaOH. Agave atroverance fiber is not purely cellulosic fiber. Percentage composition of different portion of the raw fiber was also determined. It contains α-cellulose, hemicellulose, nitrogenous matter, mineral matters and miscellaneous. The retted fibres were tested for determination of molecular weight. The percentage loss of molecular weight was found to be more in case of chemically retted fibres owing to the enhanced digestibility of lignocellulosic material by 4% sodium chlorite solution. Contrary to this, biological retting showed higher molecular weight due to the presence of higher cellulosic matter and removal of pectic substabces.