Chemical Composition Of Fibers Research Articles

Kenaf bast cellulosic fibers hierarchy: A comprehensive approach from micro to nano

Cellulosic fibers from kenaf bast were isolated in three distinct stages. Initially raw kenaf bast fibers were subjected to an alkali pulping process. Then pulped fibers undergone a bleaching process and finally both pulped and bleached fibers were separated into their constituent nanoscale cellulosic fibers by mechanical shearing. The influence of each treatment on the chemical composition of fibers was investigated. Moreover morphology, functional groups, crystallinity, and thermal behavior of fiber hierarchy at different stages of purification were studied using scanning and transmission electron microscopies, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA), respectively. Microscopy studies revealed that applied procedures successfully isolated nanoscale cellulosic fibers from both unbleached and bleached pulps. Chemical composition analysis and FTIR spectroscopy showed that lignin and hemicellulose were almost entirely removed by the applied treatments. XRD and TGA analyses demonstrated progressive enhancement of properties in fibers, hierarchically, in going from micro to nano scale. Interestingly no significant evolution was observed between obtained data of characterized ubnleached and bleached nanofibers.

Morphological, Physical, and Thermal Properties of Chemically Treated Banana Fiber

Environmental consciousness and increasing awareness of green technology have stirred the entire gamut of industry to move toward new materials instead of using synthetic polymeric fibers. Natural fiber can be a good substitute as they are available in fibrous form at low cost. In this study, the chemical treatment of banana fiber (Musa sapientum) using sodium hypochlorite NaClO/H2O (1:1) at 60°C is discussed. The purpose of chemical treatment is to improve the fiber-matrix compatibility, interfacial strength, physical, and thermal properties, etc. The chemical composition of fibers on treatment indicated increase of cellulose content and decrease of noncellulosic material. The changes due to chemical treatment were analyzed by Fourier transform infrared and X-ray diffraction methods. Scanning electron microscope studies revealed the changes in surface morphology after chemical treatment. And also, the treated fibers showed reduced water uptake and improved thermal properties.

Analysis on Fast-Growing Black Poplar Branch Used as Raw Materials for APMP Pulping and Papermaking

Fiber morphology, chemical composition and wood characteristic of fast-growing black poplar branch were studied. Meanwhile, pulping performance of it used for alkaline peroxide mechanical pulp (APMP) was discussed preliminarily. The research results showed that the fast-growing black poplar branch can be used as raw materials for APMP pulping and papermaking.

Structural changes during superplastic deformation of high-strength alloy 1933 of the Al-Mg-Zn-Cu-Zr system

The strain rate-temperature conditions of manifestation of the effect of high-temperature superplasticity by samples of an 1933 alloy have been established. Features of the structural state, phase composition, and deformation relief of samples of this alloy have been investigated. It has been established that grain-boundary sliding occurs intensely along both boundaries of ultrafine grains and boundaries of coarse polygonized grains parallel to the tension axis of the sample. In near-surface grain-boundary pores and in cracks that were formed and developed at the surface of the working part of these samples in the course of superplastic deformation, fiber structures were detected. The chemical composition of fibers has been investigated. The kinetics of the occurrence of phase transformations in the 1933 alloy in the course of heating of its samples to the temperature of tests has been studied, and probable causes for partial melting of the 1933 alloy have been analyzed. Fracture mechanisms for the samples deformed superplastically under the optimum conditions have been established.

Sustainable Green Composites: Value Addition to Agricultural Residues and Perennial Grasses

This work has explored the potential use of lignocellulosic agricultural residues like soy stalk, corn stalk, wheat straw, and perennial grasses, like switchgrass and miscanthus, as reinforcement for engineering value-added biobased composite materials. The effect of incorporating 30 wt % lignocellulosic fibers into a biodegradable polymer matrix comprising a pre-blend of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(butylene adipate-co-terephthalate) (PBAT) has been investigated. Results of this work explain that fiber chemical composition and fiber length distribution provide a complementary effect on the mechanical and thermal properties of the resulting biobased composites. Comparing the effects of all the fiber types, miscanthus (MS)-based composites, showed slightly higher tensile strength, and Young’s modulus improved by 104%. The highest heat deflection temperature of 110 °C was obtained with PHBV/PBAT/MS composites. This study has revealed prospects for hybridization of these lignocellulosic fibers to fabricate hybrid composites with enhanced performance.

Chemical, morphology and thermal evaluation of cellulose microfibers obtained from Hibiscus sabdariffa

Cellulose is the most abundant biomass material in nature and finds a range of application. Cellulose microfibers were extracted from Hibiscus sabdariffa fibers by steam explosion technique. Structural and surface analysis of the microfibers showed a reduction in diameter and changes in surface morphology from that of the raw fibers. The chemical composition of fibers were analyzed according to the TAPPI standards and showed increase in α-cellulose content and decrease in lignin and hemicelluloses for the microfibers. This has been further confirmed by SEM, XRD and FTIR results. Thermal characterization showed enhanced thermal stability of celluloses microfibers compared to raw fibers.

Characterization of flax fibres modified by alkaline, enzyme, and steam-heat treatments

Flax fibres are being considered as an environmentally friendly alternative to synthetic fibres in fibre-reinforced polymer composites due to their low density, biodegradability, and high mechanical strength. Previous work has found that the surface properties of natural fibres can be modified by chemical treatment and other treatment methods. This study focused on the effect of different treatments using alkaline, enzyme, and steam-heat, respectively, on some surface characteristics of flax fibre, e.g. physical, chemical, and thermal stability. Using scanning electron microscopy (SEM), treated fibres were observed to have smoother surfaces than untreated fibres. Chemical composition of fibres was found to be modified after treatment as characterized by Fourier transform infrared spectroscopy (FTIR). The crystallinity index and thermal stability of flax fibres were increased after certain treatments as determined by X-ray diffraction (XRD) and thermogravimetric analysis (TGA), respectively. The wettability of treated fibre by water was improved compared to the untreated sample.

Enzymatic treatment of mechanochemical modified natural bamboo fibers

Natural bamboo fibers have attracted growing demands in textile industry due to benefit from their excellent properties and renewable and abundant resource; however, there are still limitations for their application in textile industry because of their poor quality. For this reason, enzymes treatments on mechanochemically modified natural bamboo fibers were conducted to extract noncellulosic matters from finer natural bamboo fibers in this paper. Four enzymes, pectin lyase, xylanase, laccase, and cellulase, were used to remove pectin, hemicellulose, lignin and to loosen the compact structure of fibers, respectively. Furthermore, the concentrations of four enzymes were optimized in terms of fiber chemical composition, weight loss, fineness, and tenacity to obtain high quality fibers. An obvious reduction in amount of noncellulosic substances and also a remarkable improvement in fineness in the modified fibers can be found from the experimental results. The optimum parameters are determined as: 0.6 % pectin lyase, 1.2 % cellulase, 0.3 % xylanase, and 1.2 % laccase; and the natural bamboo fiber thus obtained is 77.51 % in cellulose content, 2.81 tex in fineness, and 2.62 cN/dtex in tenacity.

Influence of mild alkaline treatment on the cellulosic surfaces active sites

Agro-residues fibers are inexpensive environmentally friendly alternatives to synthetic fibers in fiber-reinforced polymer composites. The natural fiber properties and bondability with adhesive can be modified by subjecting the fibers to a pre-treatment procedure. The knowledge of the modified fibers surface properties is essential to explain and predict their applications. The present study is focused on the effect of alkaline treatment on the surface characteristics of stalk fibers from rapeseed, tobacco, cotton, lemon balm and kiwi. The chemical composition of fibers and Fourier transform infrared spectroscopy show components extraction and the X-ray diffraction show improvement in the crystallinity index of the treated fibers. But only the IGC analysis allows us to know in detail the alterations on the fiber surface and the effect on the adhesion of the fibers. IGC shows that alkaline treatment produces changes in the nature and number of the active sites, responsible for the physico-chemical activity of the surface of the fibers. The fiber hydrophobicity was improved by the increase of more energetic and active sites in the surface. Also, the creation of new basic active sites and removal of acidic active sites from the fiber surface due to alkaline treatment has been clearly shown.

Investigation on the surface properties of chemically modified natural fibers using inverse gas chromatography

This paper presents the application of inverse gas chromatography (IGC) technique for characterization and comparison of the surface properties of the natural fibers as reinforcement fillers in wood plastic composites. The effects of chemical modification using 1% NaOH were also studied. The fibers used for this work were Iranian cultivated eucalyptus, spruce, bagasse, and wheat straw. Chemical composition of fibers was found to be modified after treatment as characterized by Fourier transform infrared spectroscopy (FTIR). The crystallinity of fibers and the specific interaction was improved by the alkaline treatment, with more relevance to the agro-fibers. The IGC shows also a general increase in the wettability of the modified fiber when compared with the raw (unmodified) samples. Alkaline treatment achieves the best overall improvement in the properties evaluated of the agro-fibers when compared to the wood fibers.

Isolation and characterization of cellulose nanofibrils from wheat straw using steam explosion coupled with high shear homogenization

Cellulose nanofibrils of diameter 10–50 nm were obtained from wheat straw using alkali steam explosion coupled with high shear homogenization. High shear results in shearing of the fiber agglomerates resulting in uniformly dispersed nanofibrils. The chemical composition of fibers at different stages were analyzed according to the ASTM standards and showed increase in α-cellulose content and decrease in lignin and hemicellulose. Structural analysis of steam exploded fibers was carried out by Fourier Transform Infrared (FT-IR) spectroscopy and X-ray diffraction (XRD). Thermal stability was higher for cellulose nanofibrils as compared to wheat straw and chemically treated fibers. The fiber diameter distribution was obtained using image analysis software. Characterization of the fibers by AFM, TEM, and SEM showed that fiber diameter decreases with treatment and final nanofibril size was 10–15 nm. FT-IR, XRD, and TGA studies confirmed the removal of hemicellulose and lignin during the chemical treatment process.

Structure, morphology and thermal characteristics of banana nano fibers obtained by steam explosion

In this work, cellulose nanofibers were extracted from banana fibers via a steam explosion technique. The chemical composition, morphology and thermal properties of the nanofibers were characterized to investigate their suitability for use in bio-based composite material applications. Chemical characterization of the banana fibers confirmed that the cellulose content was increased from 64% to 95% due to the application of alkali and acid treatments. Assessment of fiber chemical composition before and after chemical treatment showed evidence for the removal of non-cellulosic constituents such as hemicelluloses and lignin that occurred during steam explosion, bleaching and acid treatments. Surface morphological studies using SEM and AFM revealed that there was a reduction in fiber diameter during steam explosion followed by acid treatments. Percentage yield and aspect ratio of the nanofiber obtained by this technique is found to be very high in comparison with other conventional methods. TGA and DSC results showed that the developed nanofibers exhibit enhanced thermal properties over the untreated fibers.

Determination and analysis of physical characteristics and fiber chemical composition of biogas residue.

Determination and analysis of physical characteristics and fiber chemical composition of biogas residue.

Banana fibers and microfibrils as lignocellulosic reinforcements in polymer composites

Banana plant waste, as lignocellulosic fiber, was treated with alkaline pulping and steam explosion to produce banana fibers and banana microfibrils. The chemical composition of the ensuing fibers and microfibrils was determined. The chemical modification, with maleic anhydride, of the produced particles was further carried out. The FT-IR analysis and scanning electron microscopy observations of the resulting modified and unmodified banana fibers were investigated. Composite materials were processed from these natural unmodified and maleated lignocellulosic fibers using polyethylene as the polymeric matrix. The thermal and mechanical properties were studied by differential scanning calorimetry (DSC) and tensile tests, respectively. The morphology of processed composites was studied by scanning electronic microscopy (SEM). Better compatibility and enhanced mechanical properties were obtained when using banana microfibrils. The chemical composition of fibers, in terms of lignin and cellulose, as well as their degree of crystallinity, were found to have a strong influence on the mechanical properties of the composites.

The Influence of Surface DBD Plasma Treatment on the Adhesion of Coatings to High-Tech Textiles

The surface of high-performance poly(ethylene terephthalate) (PET) fibers is difficult to wet and impossible to chemically bond to different matrices. Sizing applied on the fiber surface usually improves fiber wetting, but prevents good adhesion between a matrix and the fiber surface. The present study demonstrates that the plasma treatment performed by Surface dielectric barrier discharge (Surface DBD) can lead to improved adhesion between sized PET fabric and polyurethane (PU) or poly(vinyl chloride) (PVC) coatings. Moreover, it points out that this plasma treatment can outperform current state-of-the-art adhesion-promoting treatment. Plasma treatment of sized fabric was carried out in various gaseous atmospheres, namely N2, N2 + H2O, N2 + AAc (acrylic acid) and CO2. The adhesion was assessed by a peel test, while wettability was evaluated using strike-through time and wicking rate tests. Changes in fiber surface morphology and chemical composition were determined using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. Only the CO2 plasma treatment resulted in improved adhesion. As indicated by the analyses, increased surface roughness and the incorporation of specific oxygen-containing groups were responsible for enhanced adhesion. The results presented were obtained using a plasma reactor suitable only for batch-wise treatment. As continuous treatment is expected to provide higher homogeneity and, therefore, even better adhesion, a scaled-up Surface DBD plasma system allowing continuous treatment is presented as well.

Biosorption of heavy metal ions from aqueous solutions by short hemp fibers: Effect of chemical composition

Sorption potential of waste short hemp fibers for Pb 2+, Cd 2+ and Zn 2+ ions from aqueous media was explored. In order to assess the influence of hemp fiber chemical composition on their heavy metals sorption potential, lignin and hemicelluloses were removed selectively by chemical modification. The degree of fiber swelling and water retention value were determined in order to evaluate the change in accessibility of the cell wall components to aqueous solutions due to the fiber modification. The effects of initial ion concentration, contact time and cosorption were studied in batch sorption experiments. The obtained results show that when the content of either lignin or hemicelluloses is progressively reduced by chemical treatment, the sorption properties of hemp fibers are improved. Short hemp fibers are capable of sorbing metal ions (Pb 2+, Cd 2+ and Zn 2+) from single as well as from ternary metal ion solutions. The maximum total uptake capacities for Pb 2+, Cd 2+ and Zn 2+ ions from single solutions are the same, i.e. 0.078 mmol/g, and from ternary mixture 0.074, 0.035 and 0.035 mmol/g, respectively.

Processing and characterization of reinforced polyethylene composites made with lignocellulosic fibers from Egyptian agro-industrial residues

Lignocellulosic fibers were extracted from Egyptian industrial crops, viz. cotton stalk, rice straw, bagasse, and banana plant waste. The chemical composition of these fibers was determined. Composite materials were processed from these natural lignocellulosic fibers using low density polyethylene and acid stearic as compatibilizer, or maleated low density polyethylene. The thermal and mechanical properties were studied by differential scanning calorimetry (DSC) and tensile tests, respectively. The morphology of processed composites was studied by scanning electronic microscopy (SEM). Better compatibility and enhanced mechanical properties were obtained when using maleated LDPE as compatibilizer. The chemical composition of fibers, in terms of lignin, cellulose and hemicelluloses contents, was found to have a strong influence on the mechanical properties of the composites.

Size Distribution, Pulmonary Deposition and Chemical Composition of Hungarian Biosoluble Glass Fibers

Compared to spherical particles, inhaled fibers may cause enhanced adverse health effects because of their specific shape, thus acting as so-called physical carcinogens. The chemical composition of fibers plays a determining role on the durability and hence may play a potential role in related health effects due to their toxic components. The physical properties, that is, length, diameter, and size distribution, and the chemical composition of fiberglass materials sampled at a Hungarian glass wool factory were investigated. The morphology of the particles was studied by optical microscopy and scanning electron microscopy (SEM), while for the chemical analysis instrumental neutron activation analysis (INAA) and SEM combined with energy-dispersive x-ray analysis (EDX) were used. Deposition fractions of the fibers in different regions of the lung and in the whole human respiratory system were computed by a stochastic lung deposition model for different flow rates and equivalent diameters, using experimentally determined size distributions.

Chemical composition, anatomy, lignin distribution, and cell wall structure of Malaysian plant waste fibers

The chemical composition, anatomical characteristics, lignin distribution, and cell wall structure of oil palm frond (OPF), coconut (COIR), pine-apple leaf (PALF), and banana stem (BS) fibers were analyzed. The chemical composition of fiber was analyzed according to TAPPI Methods. Light microscopy (LM) and transmission electron microscopy (TEM) were used to observe and determine the cell wall structure and lignin distribution of various agro-waste fibers. The results revealed differences in anatomical characteristics, lignin distributions, and cell wall structure of the different types of fibers investigated. Nevertheless, transmission electron microscopy (TEM) micrographs have confirmed that the well wall structure, in each case, could be described in terms of a classical cell wall structure, consisting of primary (P) and secondary (S 1 , S 2 , and S 3 ) layers.

Body composition, muscle fibre characteristics and postnatal growth capacity of pigs born from sows supplemented with L-carnitine

Recently, it has been shown that supplementation of sows with L-carnitine increases their plasma concentrations of insulin-like growth factor (IGF)-I, and it has been hypothesized that this may stimulate fetal myogenesis. This study was performed to investigate whether piglets of sows supplemented with L-carnitine differ in muscle fibre characteristics, chemical body composition and postnatal growth capability from pigs of control sows. Muscle fibre characteristics and chemical body composition were determined at weaning in 21 piglets of control sows and 21 piglets of sows treated with L-carnitine with similar body weights; postnatal growth capability was determined from weaning until slaughter at a body weight of 118 kg in 80 pigs of control sows and 80 pigs of sows treated with L-carnitine which had also similar body weights at weaning. Piglets of sows supplemented with L-carnitine did not differ in number, area, diameter and type (percentages of slow twitch oxidative + fast twitch oxidative fibres, and fast twitch glycolytic fibres) of muscle fibres in m. longissimus dorsi and m. semitendinosus and in chermical body composition (concentrations of dry matter, crude protein, crude fat) from piglets of control sows. Postnatal growth capability (body weight gains, feed conversion ratio) from weaning to slaughter as well as carcass composition (carcass yield, meat thickness, fat thickness) was also not different between pigs of sows treated with L-carnitine and pigs of control sows. In conclusion, data of this study do not support the hypothesis that L-carnitine supplementation of sows during pregnancy enhances fetal muscle fibre development and increases postnatal growth capability of the offspring.