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Abstract Flax (Linum usitatissimum) is a bast fiber plant known for its long fibers, making it an excellent source of pulp for paper production. In Ethiopia, flax is primarily cultivated for oil, with the residual straw utilized for papermaking. This study focuses on pulping flax straw using the Kraft process and investigates its chemical composition, proximate analysis, and morphological properties. The proximate analysis revealed an ash content of 4.13% and moisture content of 11%. Chemical composition analysis showed cellulose at 51.34%, hemicellulose at 25.20%, lignin at 14.12%, ash at 4.13%, and extractives at 5.21%. The morphological properties included a fiber length of 1.41 mm, diameter of 16.78 μm, lumen width of 9.45 μm, and cell wall thickness of 3.77 μm. Flax straw exhibited an acceptable Runkel ratio (0.8) and flexibility coefficient (56.32), placing it within the range of non-wood fibers. SEM analysis of the pulp’s morphology was conducted to assess fiber structure, including the presence of cracks. Pulp quality and length are directly linked to paper strength. Various pulping conditions were studied using a full-factorial design, with optimum conditions being 10% alkaline, 131.74°C, and 120 min of cooking time, yielding a pulp with a Kappa number of 10.45 and a yield of 40.56%. The resulting paper demonstrated standard tensile, tearing, and burst strengths, indicating that flax straw is a promising raw material for paper production.

Flax (Linum usitatissimum) is a bast fiber plant known for its long fibers, making it an excellent source of pulp for paper production. In Ethiopia, flax is primarily cultivated for oil, with the residual straw utilized for papermaking. This study focuses on pulping flax straw using the Kraft process and investigates its chemical composition, proximate analysis, and morphological properties. The proximate analysis revealed an ash content of 4.13% and moisture content of 11%. Chemical composition analysis showed cellulose at 51.34%, hemicellulose at 25.20%, lignin at 14.12%, ash at 4.13%, and extractives at 5.21%. The morphological properties included a fiber length of 1.41 mm, diameter of 16.78 μm, lumen width of 9.45 μm, and cell wall thickness of 3.77 μm. Flax straw exhibited an acceptable Runkel ratio (0.8) and flexibility coefficient (56.32), placing it within the range of non-wood fibers. SEM analysis of the pulp's morphology was conducted to assess fiber structure, including the presence of cracks. Pulp quality and length are directly linked to paper strength. Various pulping conditions were studied using a full-factorial design, with optimum conditions being 10% alkaline, 131.74°C, and 120 min of cooking time, yielding a pulp with a Kappa number of 10.45 and a yield of 40.56%. The resulting paper demonstrated standard tensile, tearing, and burst strengths, indicating that flax straw is a promising raw material for paper production. [ABSTRACT FROM AUTHOR]

This research explores the potential of agricultural waste, specifically flax straw, as a sustainable raw material for eco-friendly packaging materials. This study investigates a three-stage delignification process involving nitric acid, alkaline treatment, and organosolvent solutions. This method effectively removes lignin from the straw, resulting in high-quality technical pulp with 67.7% α-cellulose and a significantly reduced ash content (8.5%). X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were employed to characterize the treated flax straw. XRD analysis revealed changes in the cellulose structure, while TGA indicated enhanced thermal stability compared to untreated straw. Microscopic analysis of the pulp fibers shows a parallel and aligned arrangement, suggesting a high fiber content and a strong paper lattice. The particle size distribution of the ground pulp, influenced by fiber size, has implications for the packing density and mechanical properties of the final product. This study demonstrates the potential of agricultural waste as a sustainable source for packaging materials, contributing to the circular economy and waste reduction. [ABSTRACT FROM AUTHOR]

Biofuels are a clean source of energy and they are produced from cheap and renewable sources such as lignocellulose biomass. Lignocellulose biomass composition and structure affect its hydrolysis to fermentable sugars. This is due to the cellulose crystallinity and the presence of non-hydrolyzed lignin. As a result, the obtained biofuels are of a low yield. A pretreatment step can be added before the hydrolysis to delignify and decrease the crystallinity of lignocellulose biomass. Pulsed electric field was found to increase the permeability of plants tissues. In this study, flax straw was pretreated using pulsed electric field and the yields of glucose, cellobiose, and xylose, with respect to untreated flax straw, from the hydrolysis increased by 25%, 67%, and 12%respectively. [ABSTRACT FROM AUTHOR]

Introduction. The efficiency of separating long flax fiber from the flax straw largely depends on the structural parameters of the layer of flax stems. Modern fluffers for flax strips create random distortions and intersection of the layer of flax stems under the pick-up drum. These disadvantages of existing machines are minimized in an experimental fluffer, in which a layer of flax stems moves over the pick-up drum with a kinematic mode indicator equal to one. Aim of the Article. The study is aimed at finding means and methods for preserving the structural parameters of the layer of flax stems when fluffing flax straw strips. Materials and Methods. Experimental studies were carried out according to existing and newly developed methods, and the analysis of flax fiber was carried out according to the current GOST standards. The experiments were carried out on the flax strips formed by the LC-4A flax harvester. After grass sprouted through the strips of flax stems, they were fluffed with the serial machine VL-3 and an experimental fluffer. For each variant, the necessary measurements of the main structural parameters of the stem strip and collection of samples for analysis were made before the unit passed and after fluffering the flax stem strip. The results of measurements and processing of samples were processed using the methods of mathematical statistics. Results. It was found that macro-bends of the original and processed flax strips were in all the experiments. At the same time, the range of changes in the curvature of the flax strip outside the cutoff frequencies expanded 2.3 times under the influence of the working tools of the serial tedder VL-3. The randomness of these pulsations was caused by an increase in the distortion and elongation of the flax stems in the strip by 6.0° and 6.9%, respectively. At the same time, the experimental fluffer produced the smallest changes in the structural parameters of the flax stem layer. The technological evaluation of the flax straw confirmed the advantages of the experimental fluffer in comparison with the serial VL-3, which has an average production of long fiber higher by 0.65% and 0.5 units of number. Discussion and Conclusion. The analysis of the obtained results indicates the practicability of fluffing flax strips by picking up and moving the stems from above the pick-up drum with its kinematic mode index equal to one.

Livestock dung, discarded crop straws, and residual plastic film are the primary agricultural non-point sources of pollution. For livestock dung and discarded crop straw, the general treatment focuses on compost, animal fodder, industrial raw material, and new energy. The development of degradable mulch film is the main way to solve pollution from residual plastic film. However, an effective way to solve the above three types of pollution simultaneously and use them for ecological circular agriculture has been less studied. In this study, using cow dung and flax straw wastes as raw materials, we prepared natural, fibre-based paper mulch using the rapid-Kothen method and analysed the film-forming mechanism. Based on the Van Soest method, the cow dung and flax straw waste contain abundant cellulose fibres: 36.75% and 54.69%, respectively. The tensile strength and tear strength of fibre paper mulch are 1.87 kN/m and 19.91 N/mm, respectively. To enhance the adaptability of the fibre paper mulch in humid environments, the surface of the mulch was treated with alkyl ketene dimer (AKD). The AKD-coated fibre paper mulch displays hydrophobic properties, indicated by a contact angle of 128° ± 2°. It has a wet tensile strength of 0.64 kN/m and a wet tear strength of 8.23 N/mm. Additionally, it exhibits a dry tensile strength and a tear strength of 2.13 kN/m and 16.43 N/mm, respectively. Notably, the dry tensile strength is increased by 16.31%. In this way, the livestock dung and discarded crop straw can be reused, reducing dung pollution and straw burning in livestock farms, and the final products can alleviate the residual film pollution simultaneously. [ABSTRACT FROM AUTHOR]

To improve the utilization rate of flax straw and the clean treatment of livestock manure, an experimental study was conducted on the process and performance of making fibre paper films by mixing cow dung and flax straw fibre. Cow dung and flax straw were used as the main raw materials, and functional additives were not added. The whole technological process of the pretreatment, the beating process, the determination of the beating degree, the basis weight of the paper, papermaking, drying, sample cutting, and the determination and analysis of the related mechanical properties of the film-making materials were studied. In this study, the Box–Behnken experimental design principle in the response surface methodology was adopted, and the effect of each factor on the tensile strength and tear strength of fibre paper film made of mixed fibres was determined using the combined experimental design comprising four factors and three levels centres. The results showed that the optimum technological parameters were as follows: the beating degree of the cow dung fibre was 37 °SR, the beating degree of the flax straw fibre was 85 °SR, the paper basis weight was 80 g/m2, and the addition of flax straw fibre was 65%. At a drying temperature of 80 °C and a drying time of 8 min, under the conditions of the hybrid fibre paper film placed in the laboratory environment (humidity of 30%~40%, temperature of 18 °C) for 24 h, the measured tensile strength was about 8.26 MPa, and the tear strength was about 19.91 N/mm. This study provides a reference that can be used for the further study of fibre paper film. [ABSTRACT FROM AUTHOR]

This study investigates the production of furfural from flax straw biomass through hydrothermal hydrolysis using solid acid catalysts. Specifically, the potential of Glu–TsOH–Zr, Glu–TsOH–Ti, and Glu–TsOH catalysts in furfural production from flax straw biomass and pure xylose was examined. Various characterization techniques such as NH3-TPD, N2-Physisorption, XRD, SEM–EDS, and FTIR were employed to analyze the catalysts' characteristics. The effect of reaction residence time (0–120 min) and reaction temperature (170–210 °C) on furfural yield was studied. Additionally, the optimal solvent ratio in a two-phase liquid system and the kinetics of the furfural production process were determined. Results showed that the Glu–TsOH–Zr catalyst exhibited increased furfural yield from flax straw without promoting furfural degradation. The catalyst capacity order in the hydrothermal hydrolysis process was found to be Glu–TsOH–Ti > Glu–TsOH–Zr > Glu–TsOH, and these catalysts yielded higher furfural from flax straw compared to previous studies. A first-order irreversible series reaction was identified for furfural production, with temperature having a greater impact on the reaction than the degradation process. The proposed model demonstrated a good fit, with an average absolute deviation of 5.9%. This study presents the kinetics and a comprehensive parametric analysis of a stable and selective sulfonated carbon-based zirconia catalyst for furfural production from flax straw, excluding xylose degradation products. The findings contribute to understanding the potential and limitations of flax straw liquefaction and provide insights for further advancements in catalyzed reactions for renewable fuel production. [ABSTRACT FROM AUTHOR]

Introduction. During fiber-flax harvesting, the working tools of pulling units actively interact with the flax plants. The flax pulling unit with transverse tape-disc pulling channels is characterized by the separation of technological plant flows resulting in the loss of seeds and damage to the flax stems. The aim of the work is the theoretical and experimental substantiation of changes in the design of the pulling units with transverse tape-disc pulling channels by eliminating the separation of technological plant flows during flax pulling. Materials and Methods. Experimental studies to substantiate the parameters and modes of the pulling unit operation were carried out according to available and newly developed methodologies, while the evaluation of flax products was carried out according to current GOSTs (Russian National standards). There was determined the influence of the flax ripeness stages, flax yield, and a type of pulling unit on the indicators of separation of technological plant flows and on seed losses. The influence of the pulling unit type, operating width of the pulling section, and the pulling unit speed on the indicators of processing flax straw was also established. Results. There was obtained the dependence for determining the flax stem base elongation, taking into account the seed boll cohesion. The design of the modernized flax pulling unit was used to assess the effect of reducing the flax stem base elongation and eliminating the separation of technological plant flows during pulling on the reduction of seed loss and increase in the yield of flax longs. In the improved flax harvester, the frame elements are positioned behind the pulling unit. Thanks to the modernization of the pulling unit, the flax straw was of higher quality: 1.5 numbers at THLN-1.9M and 1.25 numbers at THLN-1.9P. Discussion and Conclusion. The modernized pulling unit THLN-1,9M during flax harvesting in the stage of early yellow ripeness, compared with the unit THLN-1,9P, can reduce seed loss by 1.4-2.0%, increased output of long fiber by 1.3%. The production of flax longs increases to 0.45 of its number.

[Display omitted] • Developed a detailed kinetic model to simulate slow and fast biomass pyrolysis. • Fast pyrolysis produced high oil and slow pyrolysis produced high char content. • Maximum exergy efficiency was 94.8% for slow and 98.2% for fast pyrolysis. • 13% of the total cost is associated with the exergy destruction. Pyrolysis, a viable method for converting organic material into value-added products, has significant potential to reduce environmental footprints. In this study, slow and fast pyrolysis of flax straw biomass was modeled in an Aspen Plus. This was followed by validation of the product yields (biochar, bio-oil, and gas) with our earlier experimental data with slow pyrolysis. The Aspen Plus model incorporated a kinetic reaction model based on the three main components of lignocellulosic biomass: cellulose, hemicellulose, and lignin. The kinetic reaction model includes 21 reactions representing the volatilization, degradation, and decomposition processes inherent in biomass pyrolysis. The Aspen Plus confirmed the consistency of the findings by validating the biogas yield (which ranged from 21.4 wt% to 38.6 wt%), biochar (29.5 wt% to 42.8 wt%), and bio-oil (35.8 wt% to 40.3 wt%). The robustness of the model was verified by experimental data using controlled pyrolysis tests of flax straw feedstock at different temperatures, showing strong agreement. The kinetic reaction model is adaptable for predicting pyrolysis yields for various lignocellulosic biomass feedstocks under typical pyrolysis conditions. Furthermore, energy and exergy analyses were briefly assessed using the product yields, pyrolysis temperature, and heating values of the products at slow and fast pyrolysis conditions. The conventional exergy analysis showed an exergy efficiency of 87–95 % with varying temperatures from 400 to 600 °C for slow pyrolysis, with the highest efficiency obtained at 500 °C. Fast pyrolysis has resulted in a higher exergy efficiency than slow pyrolysis, ranging from 89 % to 98 %. [ABSTRACT FROM AUTHOR]

Flax and wheat straw were stored at −20°C, 4°C, or 20°C for up to 28 days as a pre-treatment to wax extraction performed using n-hexane or by immersion in liquid nitrogen. The epicuticular wax separation yield improved significantly after 28 days of storage at 4°C for both flax and wheat samples. Controlled-temperature storage resulted in a loss of selectivity in regard to epicuticular wax recovery from flax straw. Alterations within the epicuticular waxes that occurred during controlled-temperature storage were analyzed using scanning electron microscopy. Thermal analysis of the waxes using DSC yielded findings that were in concordance with the chemical results. [ABSTRACT FROM AUTHOR]

This article presents the results of research concerning lightweight composites produced on the basis of lime, cement, and clay binders, with the addition of perlite, hemp shives, and flax straw. Tests of physical and mechanical properties of composites were performed and their basic characteristics were determined, i.e. absorptivity, density, thermal conductivity coefficient, and compressive and flexural strength. The study was conducted to determine the use of hemp and flax composites to fill the frames of a wooden house. The results prove that the composites have low thermal conductivity, apparent density, and low strength properties compared with conventional building materials.

Abstract In this study, the throughput and kinetics of furfural production by the liquefaction of wet flax straw was conducted. The reaction was carried out in the temperature range of 200–325 °C, pressure of 0–60 bar, retention time in the range of 0–120 min, catalyst amount of 0.5–1.5 g, and a flax straw mass fraction of 10% using three types of solid acid catalysts: γ–alumina, H-ZSM-5, and silica-alumina. The results show that the highest yield of furfural was obtained using γ-alumina catalyst of weight of 1 g and the highest conversion of 66% at 325 °C. It was found that the acidity of the catalyst is key to enhance the production of furfural with a direct correlation with the number of the Lewis acid sites. The catalysts in order of the number of Lewis acid sites was found to be γ–alumina > H-ZSM-5 > silica-alumina. The kinetic data were also developed using an empirical rate model. The apparent activation energy was found to be 9.46 kJ/mol and the reaction order was 2.0. Also, the model-predicted rate showed a good agreement with the experimental rates with more than 91% accuracy. Highlights • Flax straw hydrothermal liquefaction for furfural production. • Maximum yield for furfural production using catalyzed and non-catalyzed liquefaction. • Solid acid catalysts with different Brϕnested to Lewis acid sites were tested increased furfural yield. • Parametric study for liquefaction of flax straw for furfural production. • Interrelationships between catalysts characteristics and their activity for furfural. • γ-Al 2 O 3 showed the highest activity for furfural followed by H-ZSM-5, and Si-Al 2 O 3 in all of the tested parameters. • An empirical power law model of flax straw liquefaction to furfural over alumina-based catalyst was developed. [ABSTRACT FROM AUTHOR]

Highlights • This work present the influence of starch on Earth/plante mixture in its fresh and hardened state. • The added starch increase the water demand and increases mechanical strengths in present of superplasticizer. • The studied earth/plante blocks is designed for the production of non-bearing blocks. • Several studied blocks give mechanical characteristics satisfying the EN 12859 standard. Abstract In this paper, we study the influence of two types of starch on earth hemp or flax straw mixtures at fresh and hardened states. The main goal is to propose new non-load bearing earthen for indoor. The mass percentage of starch/binder (S/B) in mixtures was fixed at 1% of mass. The VEBE consistometer test has been used to fix a similar consistency between mixtures. The targeted workability has to allow an easy introduction of materials in the moulds. Adding both of starch has shown a positive effect on mixtures workability at the fresh state and mechanical resistances at the hardened state. At hardened state, mechanical and thermal-acoustic performances have been measured on laboratory samples and blocks at real scale. Results have shown a significant effect of starch on mechanical strengths. [ABSTRACT FROM AUTHOR]

The article presents the results of a study of the properties of flax straw as a raw material and as a lightweight, environmentally-friendly insulation made of a two-component mixture of flax straw and liquid glass. The flax is considered to be renewable and is a 100% natural waste product of the agriculture industry, which may be widely used as sustainable building insulation after light modifications. The ratio mixes of the two-component eco-insulation of flax straw and liquid glass (Na2O(SiO2)) have been developed in terms of sustainability principles such as environmental friendliness and energy efficiency. We used thermal analysis to compare flax straw as a raw material, and a complex insulation made of flax straw demonstrated a slower decomposition of the composite and shorter peaks, which supports the concept of the transformation of flax straw with liquid glass to increase its fire resistance properties. The peaks of the loss of mass with the exothermal process were defined for both flax samples. The thermal conductivity coefficient of the material is around 0.085 W/m K, which permits its use as an effective insulation material for sustainable buildings. [ABSTRACT FROM AUTHOR]

This study examined biocomposites based on low-density polyethylene (LDPE) and lignocellulosic fillers [wood flour (WF) and oil flax straw (FS)] selecting four size fractions of each lignocellulosic material as fillers for the composites. The primary aim was to evaluate the influence of fraction size on the composites’ basic properties; to accomplish this, the composites’ mechanical properties, thermal oxidation, thermophysical characteristics, and water absorption capacity were examined. Then microphotographs of the samples were created and length-to-diameter (L/D) ratio of the fillers was calculated, finding that the L/D ratio increased with increasing particle size. The particle size influenced the oxidative degradation and water absorption processes in composites with oil flax but not in those with WF. Biodegradation tests performed on the recovered soil found that the loss of mass in composites based on LDPE and FS was higher than in the same composites with WF. Moreover, at the initial stage of composting, the biodegradation rate correlated with the size of filler particles (i.e., the larger the particles, the higher the degradation rate of the biocomposite). [ABSTRACT FROM AUTHOR]

The article presents the results obtained in the course of a study on prospective application of flax/hemp wastes as a filling material of lime-based composites in the construction of low-energy buildings. The utilized filler comprised the hydrated lime with clay and Portland cement used as additives. The analysis involved evaluation of such properties as porosity, density, thermal conductivity, absorptivity, permeability, as well as compressive and flexural strength. Depending on the quantity of the filler, the properties of the composite changed. This, in turn, enabled to evaluate whether the utilized composite met the thermal requirements established for low-energy buildings. Afterwards, the obtained data were cross-referenced with the results gathered in the case of a room built of autoclaved aerated concrete. In order to prevent reaching the critical surface humidity, the internal surface temperature had to be calculated. Moreover, the chances of interstitial condensation occurring in the wall made of the analyzed lime–flax–hemp composite were determined as well. The study showed that the composite exhibits low strength, low density, low thermal conductivity, and high absorptivity. The external walls made of the lime–flax–hemp composite receive a limited exposure to condensation, but not significant enough to constitute any threat. The requirements established for low-energy buildings can be met by using the analyzed composite. [ABSTRACT FROM AUTHOR]

In this study, the pyrolysis of several Canadian straw biomasses was studied using a thermogravimetric analyzer and a bench-scale horizontal fixed-bed reactor, in order to better understand the devolatilization process and to obtain information about the product yields of these biomasses. The straw biomasses were converted through pyrolysis performed in a fixed-bed reactor at temperatures of 500 °C to study the influence of the feedstock on product yields. The effects of various catalysts on product yields are also discussed. When using zeolite catalysts, the bio-oil and bio-char yields of the straw pyrolysis were increased to 46.44% and 38.77%, respectively, while the bio-gas yield was decreased to 13.65%. The use of catalyst zeolite ZY-SS had the most significant effect on overall bio-oil and bio-char yields, increasing the bio-oil yield by about 2% and the bio-char yield by 8%. This catalyst had the most significant effect on the pyrolysis of flax straw, where the bio-oil yield was increased to 46.44%. In the pyrolysis of oat straw, the use of the catalyst consistently decreased the bio-gas yield; however, the bio-oil yield increased the most significantly (43.32%) with the use of catalyst zeolite ZY-NS. The use of zeolite ZY-NS also increased the bio-oil yield during the pyrolysis of barley straw (43.03%). [ABSTRACT FROM AUTHOR]

Copyright of Journal of Natural Fibers is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Flax straw of flax varieties that are grown for oil production is a byproduct which represents a considerable biomass source. Therefore its potential application for human use is of high interest. Our research has revealed that flax straw is rich in flavonoid C-glucosides, including vitexin, orientin and isoorientin. The objective of this study was to evaluate the cytotoxicity and possible proapoptotic effect of flax straw derived C-glucosides of flavonoids in the human breast adenocarcinoma cell line (MCF-7). The effects of flax straw derived flavonoid C-glucosides on cell proliferation of MCF-7 cells were evaluated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) and sulforhodamine B (SRB) assays. The expression of apoptosis-related genes was assessed by real-time PCR. Our data revealed that flax C-glucosides as well as pure compounds are cytotoxic towards MCF-7 cells and inhibit their proliferation. Moreover, the induction of apoptosis was correlated with the changes in the mRNA level of pro-apoptotic genes. Increased expression of bax and caspase-7, -8, and -9 and decreased mRNA expression of bcl-2 was observed, whereas the mRNA levels of p53 and mdm2 were not altered. These results clearly demonstrated that flax straw metabolites effectively induced growth inhibition and apoptosis in human breast adenocarcinoma cells.

Copyright of Journal of Plant Production is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Flax straw of flax varieties that are grown for oil production is a by product which represents a considerable biomass source. Therefore, its potential application for human use is of high interest. Our research has revealed that flax straw is rich in flavonoid C-glucosides, including vitexin, orientin, and isoorientin. The objective of this study was to evaluate the cytotoxicity and possible proapoptotic effect of flax straw derived C-glucosides of flavonoids in the human breast adenocarcinoma cell line (MCF-7). The effects of flax straw derived flavonoid C-glucosides on cell proliferation of MCF-7 cells were evaluated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) and sulforhodamine B assays. The expression of apoptosis-related genes was assessed by real-time PCR. Our data revealed that flax C-glucosides as well as pure compounds are cytotoxic toward MCF-7 cells and inhibit their proliferation. Moreover, the induction of apoptosis was correlated with the changes in the mRNA level of pro-apoptotic genes. Increased expression of bax and caspase-7, -8, and -9 and decreased mRNA expression of bcl-2 was observed, whereas the mRNA levels of p53 and mdm2 were not altered. These results clearly demonstrated that flax straw metabolites effectively induced growth inhibition and apoptosis in human breast adenocarcinoma cells. [ABSTRACT FROM AUTHOR]

Flax fibers are superior to E-glass fibers in terms of specific Young modulus. Many researchers have recently tried to exploit this feature and use flax fibers in polymeric composites to compete with glass fiber composites. In this work, a new type of unidirectional flax/paper reinforcement obtained after resin transfer molding with epoxy is investigated. Reinforcement's parameters (paper ply and flax ply surface densities) and manufacturing parameters (forming pressure and drying temperature) are optimized to obtain the best possible composite strength and modulus. Internal bond strength between flax and paper layers is also investigated. Results show that at equivalent V f the new flax/paper/epoxy composite is superior, in both specific strength and modulus, to another flax/epoxy composite (without the paper layer). It also surpasses the specific stiffness of a unidirectional E-glass/epoxy composite and the specific strength of a commercially available similar reinforcement. [ABSTRACT FROM AUTHOR]

Torrefaction is a thermo-chemical process, which is also referred to as a mild pyrolysis carried out at a relatively low temperature ranging from 200 to 300°C. During the torrefaction process, the lignocelluloses materials, such as cellulose, hemicelluloses, and lignin, undergo degradation, with the maximum degradation belonging to hemicelluloses. The present research focuses on torrefaction of the flax straw under laboratory scale. Thermo gravimetric analyzer was used to study the effect of temperature, particle size, and residence time on the torrefaction of flax straw. Proximate analysis of the char remained after torrefaction showed a significant increase in fixed carbon and ash content and a noticeable decrease in the moisture and volatile content with an increase in the temperature. Ultimate analysis was also performed for the product char. The results of ultimate analysis showed that the maximum carbon and heating value obtained were about 61% and 24 × 103kJ kg–1, respectively, for higher particle size (1,200 µm) and at higher temperature (300°C). The kinetic analysis showed an activation energy of 76.64 kJ mol–1for the particle size of 925 µm and for the residence time of 60 min. The experimental results of the torrefaction of flax straw indicate that the temperature has a greater effect on torrefaction process than the residence time and the particle sizes chosen for this study. [ABSTRACT FROM AUTHOR]

Flax ( Linum usitatissimum L.) is a potential winter crop for the Southeast USA that can be grown for both seed and fiber. The objective of this research was to evaluate the effect of irrigation on flax straw, fiber, and seed yield of fiber-type and seed-type cultivars at different flax growth stages. The study was conducted during the winter growing seasons of 2010/2011, 2011/2012, and 2012/2013 near Florence, SC. Four fiber-type cultivars and one seed-type cultivar were grown with and without irrigation for two years. The four fiber-types were evaluated for straw and fiber yield in the third year. Soil water was monitored to trigger irrigations. Irrigation was applied before all four harvests in 2010/2011, before only the last harvest in 2011/2012, and was not applied in 2012/2013. Straw harvests were made at the onset of flowering, 10 days past the onset of flowering, 20 days past the onset of flowering, and when seeds were mature. Seed harvests were made at the end of the 2011/2012 and 2012/2013 growing seasons. In 2010/2011, plots had to be replanted in February so crop development was delayed. Irrigation increased straw yield at the last three harvests in that year. In the other two years, when planting occurred at normal times in the fall, irrigation did not influence straw or fiber yield. Irrigation had no significant effect on seed yield. The fiber-type cultivars did not differ for straw or fiber yield. At the onset of flowering harvest, the seed-type cultivar had similar fiber content to the fiber-type cultivars. The fiber-type cultivars had higher fiber content in later harvests. The results support previous research in that fiber-type cultivars appear viable for production as fiber winter crops in the region. The results also suggest that high straw yielding seed-type cultivars could be used, especially in systems with early straw harvests. [ABSTRACT FROM AUTHOR]

Water retting is a traditional retting method that enables the low-cost production of bast fibers. This study investigated the retting of flax straws by distilled water for three different durations at room temperature in laboratory condition. The retting quality was evaluated in terms of the weight loss and degumming rate together with the fiber properties, which included color, linear density, and tensile properties. The degumming rate was defined as the percentage change in pectin content of phloem regions from the raw flax to water-retted flax. It was found that the dissolution of pectin and other contaminating materials during the beginning retting stage must have played an important role in pectin (content) and weight loss besides pectin degradation, and water retting gradually improved both the apparel properties, such as whiteness and fineness, and the mechanical properties of the fibers. Given the results, a water retting duration of six days should be sufficient to provide sound retting efficiency and reasonable fiber properties. [ABSTRACT FROM AUTHOR]

The study presents physical phenomena that occur in the physical–mechanical process of degumming of fiber from flax straw. Moreover, the effect of liquid flow through the straw has been determined by analysis of the mass exchange (motion) according to the principles of fluid mechanics.It was shown that conditions of the degumming process, especially the temperature, have a significant effect on acceleration of the mass exchange.The analyses of the results indicated that the developed model laboratory device allowed for evaluation of the mechanism of mass exchange by slow laminar liquid flow. The evaluation of the degumming process with convective mass motion at a higher speed of liquid flow was based on model tests of hydrodynamic washing of three types of gels: fruit pectin, animal gelatin and starch from linen fabrics. It was shown that temperature is a decisive factor affecting the washing out of gels. Better washing out was achieved by using diffusive penetration of water into the gel structure at the initial phase of the process. Using the dynamic washing out of the gels with a water stream of high flow speed (at the m/s range) shortened considerably the washing time. [ABSTRACT FROM PUBLISHER]

Micromechanical models usually applied to predict the mechanical properties of short glass fibre reinforced composites were used to evaluate the Young’s modulus and tensile strength of flax fibre reinforced polypropylene. Due to lack of accuracy between the experimental results and the existing models, a new adjustment to the Kelly-Tyson model was proposed. The changes were based on the understanding of the microstructure obtained in polypropylene/flax fibre composites produced by injection moulding with different flax fibre content. The mechanical properties were interpreted based on real fibre loading, fibre orientation, fibre dimension distribution and morphology of the composites. Lack of fibre/matrix adhesion, strong fibre damage and changes on the crystallization behaviour of polypropylene in the presence of flax fibres affect the mechanical strength, stiffness and elongation of the composites. The Kelly-Tyson’s model used for tensile strength prediction was modified to take into consideration the fibre property variability due to the large distribution of fibre shape ratio induced by the process. Finally, matrix modulus has been adjusted to take into account the change of crystallinity with fibre content. A better description of the mechanical properties is obtained using the proposed approach, resulting indeed in an excellent approximation to the modulus of the composite. [ABSTRACT FROM PUBLISHER]

There is substantial interest in the application of biomass as a renewable fuel or for production of chemicals. Flax straw can be converted into valuable chemicals and biofuels via liquefaction in sub-critical water. In this study, the yield of furfural and the kinetics of flax straw liquefaction under sub-critical water conditions were investigated using a high-pressure autoclave reactor. The liquefaction was conducted in the temperature range of 175–325 °C, pressure of 0.1 MPa–8 MPa, retention time in the range of 0 min–120 min, and flax straw mass fraction ( w F ) of 5–20 %. Also, the effect of acid catalysts on furfural yield was studied. The kinetic parameters of flax straw liquefaction were determined using nonlinear regression of the experimental data, assuming second-order kinetics. The apparent activation energy was found to be 27.97 kJ mol −1 while the reaction order was 2.0. The optimum condition for furfural yield was at 250 °C, 6.0 MPa, w F of 5% and 0 retention time after reaching set conditions. An acid catalyst was found to selectively favour furfural yield with 40% flax straw conversion. [ABSTRACT FROM AUTHOR]

The paper investigates the influence of the baler feed to the pins of the picking up drum on the damage of straw stalks in a bale considering the distance of the straw layer from the centre of a bale to its periphery. It also explains the change in the straw damage from the centre of a bale to its periphery. The author analyzes the damage of straw stalks in a bale depending on its tightness when using pickup balers with chambers of variable and invariable capacity. [ABSTRACT FROM AUTHOR]

Char gasification has been studied in different ways with different feedstock; however, the fundamental studies about the variation of char reactivity with different combination of parameters are still required in order to design the biomass char gasification process in large scale unit. In this work, char from flax straw pyrolysis was used for gasification with different partial pressure of CO2, different temperature and particle size. Results showed that 375-µm particle sizes of char has higher reactivity compared to other particle sizes and the inhibition effect was also less at 375-µm particle size. Kinetic parameters varied for gasification reaction with different particle sizes and the average activation energy was 196 kJ/mol and the order of the reaction was approximately 1. Inhibition studies with the addition of CO in the gasifying agent proved that CO molecules interfere significantly and reduced the reactivity. ANOVA test showed that the temperature plays a vital role in char reactivity. The particle sizes of 375 and 800 µm along with the CO2 partial pressure of 0.35 bars are the best combination for achieving the maximum reactivity. © 2012 Canadian Society for Chemical Engineering [ABSTRACT FROM AUTHOR]

Abstract: The influence of pyrolysis temperature and residence time on the char yields and resultant char characteristics were investigated in the isothermal pyrolysis of flax straw. The pyrolysis temperature was varied in the range between 300 and 500°C and reaction residence time was varied from 15 to 60min. The char yield was found to decrease with both increasing pyrolysis temperature and residence time. The char structure and physical characteristics were thoroughly investigated by means of X-ray diffraction (XRD), temperature-programmed oxidation (TPO) and N2 physisorption techniques. The results show that the degree of porosity and graphitization increased with increasing pyrolysis temperature and time. TPO studies on the char samples corroborate well with the XRD findings and showed the presence of two types of carbon; namely, amorphous filamentous carbon and crystalline graphitic carbon. Thermogravimetric analysis (TGA) of the char was performed to understand the combustion kinetics and reactivity. Chars formed at lower pyrolysis temperatures were found to be more reactive than the chars produced at higher pyrolysis temperatures, and these findings are well supported by the TPO, TGA, N2 physisorption and XRD characterization data. Furthermore, an empirical global kinetic model was devised based on power law and used to estimate the activation energy and other kinetic parameters of both flax straw pyrolysis and char combustion processes. [Copyright &y& Elsevier]

Increasing demand for natural fibers means that flax is considered as an alternative to cotton. Economic supply of fibers depends on optimal fiber extraction. This paper investigates the effect of chemical composition of flax stems on their mechanical properties. Dynamic mechanical analysis monitors changes in stem properties during different stages of plant maturation. Sequential chemical extraction enables the role of chemical components to be studied. Knowledge of the stem mechanical properties can assist in determination of both optimal harvest date for a flax crop and the level of mechanical decortication required for optimal fiber separation and cleanliness. [ABSTRACT FROM AUTHOR]

Response surface methodology (RSM) was used to optimize supercritical carbon dioxide (SC-CO2) extraction of wax from flax straw. SC-CO2 variables included flow rate (24.8, 35, 50, 65, and 75.2 g/min), pressure (132, 200, 300, 400, and 468 bar), and temperature (34.8, 45, 60, 75, and 85.2°C). The SC-CO2 extraction technique was optimized for the extraction of flax straw wax and its main constituents (fatty acids, alkanes, sterols, aldehydes, and wax esters). A second order polynomial model provided a good fit (R2 value of 0.90) for the yield of wax from flax straw. Canonical analysis revealed a maximum stationary point for wax yield of 1.26 g/100 g at a flow rate of 61.1 g/min, a pressure of 378 bar and a temperature of 75°C. The fatty acid and wax ester contents of flax wax were also fitted with a second order polynomial model with R2 values of 0.94 and 0.87, respectively. The temperature was found to be the most important factor affecting the recovery of wax. Linear and quadratic effects of temperature and interaction effects of temperature and pressure had a significant effect on the total wax yield and on the content of fatty acids, fatty alcohols, and sterols in the wax. [ABSTRACT FROM AUTHOR]

Abstract: The effects of extractives, particle size, and crop species on the contents of structural carbohydrates, lignins, and micro-components in Canada Prairie Spring (CPS) wheat, durum wheat, barley, oat, and triticale straw, as well as flax shives, were determined. Extraction for 24h in water followed by 7h in ethyl alcohol (EtOH) yielded 20.2% extractives in triticale straw. Acid insoluble lignin decreased from 17.6% in native triticale straw to 13.6% in 24h water+7h EtOH extracted triticale straw. The sample particle size influenced the values of glucan, xylan, acid insoluble lignin, ash, and extractives. Glucan, xylan, and acid insoluble lignin levels increased with increasing particle size. Protein, ash, and extractive levels decreased with increasing particle size. For flax shives, glucan, xylan, and acid insoluble lignin levels increased with increasing particle size from 19.1% to 33.2%, from 6.7% to 18.8%, and from 17.4% to 25.7%, respectively. The protein, ash, and extractive levels in flax shives decreased with increasing particle size from 6.5% to 1.9%, from 27.7% to 0.9%, and from 15.0% to 3.8%, respectively. Total glycans, lignin and extractive levels for the various straws, from the medium particle sized fraction, were 56.6–63.9, 14.7–19.4, and 6.8–20.2%, respectively. Total glycans, lignin, and extractives levels from the medium particle sized flax shives were 51.8, 25.8, and 6.46%, respectively. The composition of the medium particle size fraction reflected the composition of the corresponding original sample. [Copyright &y& Elsevier]

Abstract: Wheat straw fibers were modified via a pressurized steam treatment. The effect of steam pressure (i.e., 0.2, 0.4, 0.6, 1.0MPa) and treatment time (i.e., 5 and 10min) on chemical composition, sorption isotherm, thermal and mechanical properties of the treated fibers was investigated. Differential scanning calorimetry analysis showed that thermal characteristics of the treated straw samples were shifted indicating the improved thermal stability. The ash and extractive content of the treated straw was reduced; and the materials were likely removed when the steam was released. The removal of ash and extractives could improve the wettability of wheat straw when it is used in combination with polymer matrices. Sorption behavior study showed that steam treatment reduced the hydrophilic characteristic of wheat straw. Tensile strength of the treated straw was significantly enhanced. The tensile strength of straw after treatment at a steam pressure of 1.0MPa for 5min was more than twice higher than that of the control group. The study demonstrated that pressurized steam treatment is an effective pre-treatment process for wheat straw fibers as possible reinforcement element in polymer matrices. [Copyright &y& Elsevier]

Flax (Linum usitatissimum L.) fibers can be blended with other short staple fibers, such as cotton (Gossypium barbadense L. or Gossypium hirsutum L.), processed into a yarn, and then manufactured into a fabric. Enzyme-retting is a new, experimental method that decomposes the pectinaceous and matrix substances to separate cellulose fibers from shives using pectinase-rich enzymes and chelators. Spinning tests were used to determine how well fibers were assembled to form yarn and provided an indirect measurement of fiber properties. Miniature spinning allows expanded predictive strategies for ranking fiber production methods such as enzyme-retting and resultant yarns beyond traditional fiber testing. [ABSTRACT FROM AUTHOR]

The current situation and some problems of Russian flax sector are discussed. A five-year state program for flax sector improvement is one of the levers in managing flax production. Positive and negative sides of flax production are discussed. [ABSTRACT FROM AUTHOR]

Understanding the frictional behaviour of biomass fibre is critical for its effective utilization. There is growing research on the handling of fibrous biomass, including the effects of moisture content; however, the impacts of non-water solvents on frictional behaviour have not been addressed in the literature. In particular, the implications of adding alcohol solvents to flax shive, as could occur as part of a high-value product recovery process, remain undefined. The bulk solids frictional behaviour of flax shive was investigated using a standard shear test system. The angles of internal friction and wall friction were evaluated to determine the effects of adding varying proportions of one of three different liquids, methanol, water or isopropanol. The shear strength of flax shive, as measured by the angle of internal friction, was increased by the addition of any of the three liquids, but did not depend on which liquid or what quantity of liquid was added over the range tested. Given differences in surface tension and viscosity of the three liquids, neither property appeared to affect the angle of internal friction. The frictional behaviour of flax shive against a standard galvanized-metal wall material was measured by the angle of wall friction. Changes in the angle of wall friction were different, with a much larger increase found in the case of water addition than for either of the alcohols. Change in the angle of wall friction appeared to be related to the surface tension of the added liquid. [ABSTRACT FROM AUTHOR]

Abstract: Cereal straw, a by-product in the production of agricultural crops, is considered as a potentially large source of energy supply with an estimated value of 47×1018 J worldwide. However, there is some debate regarding the actual amounts of straw which could be removed from arable soils without jeopardizing their quality, as well as the potential trade-offs in the overall straw-to-energy chain compared to the use of fossil energy sources. Here, we used a deterministic model of C and N dynamics in soil-crop systems to simulate the effect of straw removal under various sets of soil, climate and crop management conditions in northeastern France. Model results in terms of nitrate leaching, soil C variations, nitrous oxide and ammonia emissions were subsequently inputted into the life-cycle assessment (LCA) of a particular bio-energy chain in which straw was used to generate heat and power in a plant producing bio-ethanol from wheat grains. Straw removal had little influence on simulated environmental emissions in the field, and straw incorporation in soil resulted in a sequestration of only 5–10% of its C in the long term (30 years). The LCA concluded to significant benefits of straw use for energy in terms of global warming and use of non-renewable energy. Only the eutrophication and atmospheric acidification impact categories were slightly unfavourable to straw use in some cases, with a difference of 8% at most relative to straw incorporation. These results based on a novel methodology thereby confirm the environmental benefits of substituting fossil energy with straw. [Copyright &y& Elsevier]

Thirteen pure lines from VIR flax genetic collection were evaluated for their vegetative period, production, quality of textile fibre, structure and composition of the fibre. Correlation analyses showed that strength of technical fibres was positively correlated with plant height, straw production and number of bundles per stem section and negatively with the diameter of elementary fibres. The fineness and flexibility were linked with the ratio between the areas of the fibre and xylem tissues and negatively with the relative amount of encrusting components to cellulose in fibres. The content of total fibres in the stem correlated with the content of hand decorticated fibre. It opens the possibility of approximate preliminary estimation of fibre content according to plant exterior and hand decortication. [ABSTRACT FROM AUTHOR]

The objective of this study was to analyse the performance and costs for harvest and handling of flax straw for short fibre production by means of a dynamic simulation model. In a ease study, various scenarios were simulated for a fictitious processing plant in Laholm in southern Sweden. For a handling system based on round hales, it was shown that the total harvest and handling costs could he reduced by 18% by the use of a n]ore optimal machinery system, while the variations in quality, expressed in terms of maturity and degree of retting, were reduced considerably. [ABSTRACT FROM AUTHOR]

A conference like AgFibe 2002-covering all potential agfibres such as wheat straw, linseed flax straw and hemp-allows people to put their heads together over common, shared problems. With participants drawn from several disciplines-almost 30 speakers-a deep pool of knowledge was created that made for a stimulating, exciting treat. The conference made it clear that successful fibre processing is not simply a question of growing fibre, processing it, and selling the fibre to willing and rich buyers downstream. What a successful fibre value chain does is link grower, processors and buyers into a continuum that allows for a steady, continuous and regular supply of fibre. [ABSTRACT FROM PUBLISHER]

IAA and GA3 had increased the stem thickness by increasing that of cortex, phloem fibers and xylem. Each had increased straw and fiber yield/plant, but the effect was more pronounced with GA3 than IAA. The percentage of long fibers, strength and fineness increased significantly with GA3. The latter two properties decreased with IAA. [ABSTRACT FROM AUTHOR]

The article features the flax plant. The plant's strong and enduring fiber is used as lines and nets in the prehistoric years and was later utilized in clothing and household fabrics. Flaxseed is used both as medicine and as food. The oil from these seeds is used in the Renaissance period with the rise of oil painting art. The older countries in Europe still cultivate the plant for fiber while newer countries have developed flaxseed farming. Natural and social advantages of these two distinct culture of the plant are discussed.