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1.
The Posidonia is a sea plant which is abundant on the Tunisian coasts. Important quantities of Posidonia oceanica fragments are accumulated every year on the beaches which must be cleaned every summer. This plant contains an important
ratio of cellulosic materials. On other hand, local sanitary articles industry use important quantities of absorbing materials.
The aim of this work is to take advantage of this available biomass by using it as a raw material for the preparation of some
of these absorbing materials. In this aim three cellulose qualities of various purities are prepared starting from Posidonia wastes and from these three cellulosic materials six qualities of sodium carboxymethylcellulose (CMCNa) are synthesised,
these qualities differ by there substitution degree. The performances of all these materials are evaluated in term of absorption
and retention capacities. With this end in view, three kinds of liquids are used: the deionized water, the synthetic urine
and the salt solution. Then the evaluated performances are compared with those of some commercial absorbent materials used
in local industries (industrial cellulosic pulp and superabsorbant). This comparison shows that the different prepared CMCNa
have a retention capacity largely higher than those of the commercial cellulosic pulp. The difference can reaches 405 %. The
evaluated absorption capacities of all the prepared CMCNa are generally similar to those of the commercial cellulosic pulp.
However the tested superabsorbant presents, in all cases, the best performances in term of liquid absorption and retention. 相似文献
2.
Mahmoud KhazmaAdeline Goullieux Rose Marie DheillyBoubker Laidoudi Michèle Queneudec 《Industrial Crops and Products》2011,33(1):49-56
Lightweight concrete becomes an important subject of research because of its insulating properties. The main objective of this research is to present a process improving the flax shive behaviour in a cement matrix. Flax shives stem from flax culture. It is the major product (50% of biomass weight). To be used as aggregates, shives should have a hydrophobization treatment. The aim of this work is the treatment of shives with a biodegradable elastomer: poly(PEG-co-CA). This elastomer is synthesized by the polycondensation of polyethylenglycol (PEG) and citric acid (CA). After their treatment with PEC elastomer, flax shives show a decrease in water absorption. Then, they are incorporated in a cement matrix. Mechanical properties, thermal properties and behaviour towards water (dimensional variations) of concrete are determined. The shive treatment shows an improvement in compressive and flexural strengths but an increase in thermal conductivity. The extreme dimensional variations (EDVs) and drying shrinkage (DS) decrease also with concrete prepared with treated shives compared to the standard. Overall the lightweight concrete obtained exhibits performances close to those of wood concrete. 相似文献
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为进一步提升胡麻机械化收获水平，结合胡麻作物农艺特性，研制了自走式胡麻联合收割机，能够一次性完成胡麻切割、脱粒、清选等一体化作业工序。在设定联合收割机传动系统的前提下，对其关键作业部件进行设计与选型，确定了防缠绕收获割台、切流-横轴流组合脱粒分离装置和脱粒物料清选装置相关结构与运动参数，并进行了样机作业性能试验。田间试验结果表明，当自走式胡麻联合收割机前进速度控制在2.92~6.00 km/h时，籽粒总损失率为2.26%、籽粒含杂率为1.82%，籽粒破碎率为0.98%，防缠绕合格率为100%，在机械化收获过程中割台无胡麻茎秆挂接与缠绕，排出胡麻茎秆夹带损失小，机收后胡麻茎秆割茬分布均匀，表明样机作业性能达到胡麻机械化联合收获需求，试验结果满足设计和实际作业要求。 相似文献
5.
Stability in a low temperature environment is needed for a textile to be used as winter wear. This research was presented the characteristics of fabrics by double-thin-layered coating with and without phase change materials (PCM) and several nano-sized inorganic particles (N-particles). Silica, Ag, Zr, and carbon types of N-particles were used for investigating the N-particles effect. For the experimental method, the PCM and N-particles were coated consecutively in the wet and dry coating process, respectively. The N-particles on the surface of the coated fabrics were confirmed by energy dispersive spectroscopy (EDS), and after double-layer composite coating, the adhesion durability, water vapor permeability, water penetration resistance, DSC, thermographic photography, far infrared (FIR) emission effect, and the thermal insulation of the coated fabrics were tested for investigating the performances. Their compatibility and adhesion were superior when the add-on of N-particles was 10 %. From the DSC reproducibility results, we verified that the N-particles coated fabric preserved its thermal stability by absorbing latent heat. On the other hand, the FIR emission rate and energy of the Ag N-particle based sample were not better than the control sample. 相似文献
6.
Mayssa Karray Asma Triki Christophe Poilâne Pascal Picart Mohamed Gargouri 《Fibers and Polymers》2016,17(1):88-96
In this work, a study of the dynamic dielectric analysis of the unidirectional epoxy composite: flax-fibre-reinforced epoxy (FFRE) was investigated. In this composite, three relaxation processes were identified. The first one is the water dipoles polarization imputed to the presence of polar water molecules in flax fiber. The second relaxation process associated with conductivity occurs as a result of the carriers charges diffusion. As for the third dielectric relaxation associated with the interfacial polarization effect is attributable to the accumulation of charges at the fibers/matrix interface. The analysis of the Maxwell-Wagner-Sillars (MWS) and the water dipoles polarizations using the Havriliak-Negami model revealed the high adhesion of flax fibers in the matrix. This analysis was supported by the thermal properties using a Differential Scanning Calorimety (DSC). 相似文献
7.
Isabelle Pillin Antoine KervoelenAlain Bourmaud Jérémy GoimardNicolas Montrelay Christophe Baley 《Industrial Crops and Products》2011,34(3):1556-1563
Many works deal with the mechanical properties of flax fibers cultivated for textile applications and today used for the reinforcement of polymers. Nevertheless, quantities of oleaginous flax fiber are obtained each year and not promoted. The aim of this work is to study the mechanical properties of single linseed flax fiber as a function of variety, culture year, dew-retting degree and agronomic factors. Five varieties of oleaginous flax have been characterized by tensile tests on elementary fibers and compared to four varieties of textile flax. These tensile experiments have been carried out on with the same equipment, experimental protocol and environmental conditions.The results show that interesting mechanical properties were obtained with the oleaginous variety and are close of those of textile varieties, such as Agatha or Electra. Considering the diameters and specific properties of these oleaginous fibers, we evidenced that they are good candidates for the substitution of glass fibers in composite materials. To increase the development of flax fibers, it is important to have a better control of the spread of their mechanical properties. This point could be observed with the Everest variety cultivated for 4 years and no conclusion could be made.We have evidenced that the retting degree has no influence on the diameters and mechanical properties of the fibers; the same conclusion is obtained with agronomic factors such as seeding rate and plant height. 相似文献
8.
Insulating materials based on flax short fibres were prepared and their functional properties enhanced using linseed oil. In order to improve biocomposites hydrophobicity, the linseed oil was added to the initial formulation, mixed with the fibres and finally dried after the moulding process. Thus, the average water absorption of 10-40/140 g/g oil/fibres samples was reduced up to 10 times during the first hour of immersion, compared to the reference oil-free materials. Moreover, the linseed oil polymerization inside the lignocellulosic matrix, which occurred after 20 days of drying at 50 °C, also improved mechanical and thermal behaviour of biocomposites. Spontaneous combustion phenomena related to the exothermic oxidation-polymerization of linseed oil were described as well. Therefore, the process parameters such as oil/fibres ratio, drying time and temperature, were optimized to ensure the safety of the process and to avoid self ignition of the lignocellulosic fraction at temperatures below 200 °C. 相似文献
9.
In order to develop composites with better mechanical properties and environmental performance, it becomes necessary to increase
the hydrophobicity of the natural fibers and to improve the interface between matrix and natural fibers. Graft copolymerization
of natural fibers is one of the best methods to attain these improvements. Only few workers have reported the use of graft
copolymers as reinforcing material in the preparation of composites. So in the present paper, we report the preparation of
graft copolymers of flax fibers with methyl acrylate (MA) using Fenton’s reagent (FAS-H2O2) as redox system. Synthesized flax-g-poly(MA) was characterized with FTIR, TGA/DTA, scanning electron microscopy (SEM), and
X-ray diffraction (XRD) techniques. Composites were prepared using flax-g-poly(MA) as a reinforcement and phenolformaldehyde
(PF) as the binding material. Mechanical properties of phenol-formaldehyde composites were compared and it has been found
that composites reinforced with flax-g-poly(MA) showed improvement in mechanical properties. Composites reinforced with flax-g-poly(MA)
showed better tensile strength (235 N) and compressive strength (814 N) in comparison to composites reinforced with original
flax fiber which showed lesser tensile strength (162 N) and compressive strength (372 N). Composites reinforced with flax-g-poly(MA)
shows the improved MOR, MOE, and SP. 相似文献
10.
In this study, flax shive (FS) and extracted flax shive (EFS) were fully characterized. The results showed that EFS presented lower noncellulose content, smaller porous tunnels and better thermal stability than FS. The 5 % weight loss temperature of EFS was over 200 °C, which can meet the requirements of the processing conditions for the natural fiber reinforced polymer composites. Consequently, the flax shive and extracted flax shive reinforced PP composites were prepared and characterized. It was found that the thermal stability of EFS/PP composites was better than that of FS/PP composites, and both FS and EFS behaved as nucleation agents, which could accelerate the crystallization process of PP in the composites. Mechanical test showed that EFS could be used as a reinforcing material for PP composite when compatibilizer was applied. The flexural strength and modulus of the composites containing 30 % EFS were about 8 % and 100 % higher than that of pure polypropylene, respectively. 相似文献
11.
亚麻煮漂工艺是亚麻纺纱中的一道重要工序,大量研究对该工艺作了改进。本文综述了人们在粗纱煮漂的漂前预处理、新型煮练剂或助剂、新型氧漂助剂、新型漂白剂、生物脱胶、提高纱支、提高亚麻纤维的柔软度等方面的研究,并对亚麻粗纱煮漂工艺的发展方向进行了展望,以期对以后的亚麻煮漂工艺的改进和完善提供参考。 相似文献
12.
《Industrial Crops and Products》2005,21(3):369-378
A flax fiber pilot plant is needed to process small samples of flax straw into fibers to facilitate research on retting and fiber properties. Our objective was to develop and test a modular design for a flax processing pilot plant based on a commercial line that was capable of cleaning fiber and seed flax straw from unretted, dew-retted, and enzyme-retted samples. The USDA Flax Fiber Pilot Plant (Flax-PP), which is the only research facility of this type in the United States, was designed according to the commercial ‘Unified Line’ (Czech Flax Machinery), but smaller and constructed in four individual modules. The modules and their order for processing were as follows: 9-roller calender, top shaker, scutching wheel, top shaker, 5-roller calender, and top shaker. Illustrations and diagrams of the operating modules are presented. Unretted ‘Neche’ linseed flax, dew-retted ‘Natasja’, and enzyme-retted ‘Jordan’ fiber flax were processed, and the cumulative weight loss of material at successive processing steps was determined to assess the effectiveness of cleaning. Fiber strength, fineness, and elongation were determined for the retted samples after cleaning through all the steps in the Flax-PP. A yield of fine fiber from the retted stems processed through the Flax-PP was acquired from further cleaning and refining by passage through a Shirley Analyzer. The various samples behaved differently at different stages of processing and the resulting fibers had different properties. The dew-retted Natasja fibers were stronger and finer than the enzyme-retted Jordan flax after pilot plant processing, but the Jordan fibers appeared cleaner and better retted. The Flax-PP effectively processed samples of diverse characteristics and will facilitate integrated research on retting methods for fibers with tailored properties. 相似文献
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本试验对亚麻双胚实生苗进行了详细的观察，同时进行了亚麻染色体加倍技术的深化研究，确定了现蕾期用0．05％秋水仙碱24小时处理单倍体亚麻苗的最佳时期，并获得了多份加倍材料。本文阐述了双胚亚麻无融合生殖的意义和在育种中的利用价值。 相似文献
15.
To develop waterproof breathable materials for diverse consumer applications, we used electrospinning to fabricate layered
fabric systems with varying composite structures. Specifically, we developed layered fabric structures based on electrospun
nanofiber webs with different levels of nanofiber web density, as well as different substrates and layer structures, and then
examined the breathability and waterproofness of the material. The breathability and waterproofness of the layered fabric
systems were compared with those of traditional waterproof breathable fabrics, including densely woven fabric, microporous
membrane laminated fabric, and hydrophilic nonporous polyurethane coated fabric. Different breathability and barrier performance
levels were achieved by varying the layer structure and substrates in the electrospun nanofiber web layered fabric systems.
The uniformity of the nanofiber web and lamination process also affected the barrier and comfort performances. The comparison
of waterproofness and breathability performances between the new materials and the traditional waterproof breathable materials
revealed that the layered structures based on electrospun nanofiber webs provide a higher level of resistance to water penetration
than densely woven fabrics and a higher degree of moisture vapor and air permeability than microporous membrane laminates
and coated fabrics, with a proper selection of layer structure, substrate fabric, and lamination process. 相似文献
16.
内蒙古栽培纤维亚麻始于20世纪60年代初，80年代末开始深入研究。经过科研人员的选择、培育，筛选出适合于本区种植的“黑亚六号”品种，育成了“内纤亚一号”新品种以及一系列优良品系服务于农业生产。但由于主客观原因，目前内蒙古自治区纤维亚麻原料生产停滞，供给严重短缺。因此，重点应从加大企业改革和政府支持力度、开发功能产品，开展亚麻增值技术的研究以及加强亚麻种质资源评价等方面采取切实可行措施，促进亚麻发展。 相似文献
17.
大麻纤维受热过程中内部结构和物理性能的变化规律是大麻纺织、染整和大麻纤维增强复合材料加工工艺的理论依据,本论文通过对工业用大麻精干麻、原麻纤维的热学性能测试和受热后其束纤维相对断裂强度变化的测试实验,分析了工业用大麻纤维的分解温度、分解阶段和相对断裂强度的变化规律. 相似文献
18.
亚麻鲜茎雨露沤制技术的初步研究 总被引：5，自引：1，他引：4
雨露麻以其生产方式简单,成本低,不污染环境而被广泛应用,但传统的雨露麻采用人工收获,在多雨季节里原茎保存困难,常发生霉烂。给工农业均造成损失。鲜茎雨露沤麻技术的提出解决了这一问题,同时使沤麻时间提前10天左右,亚麻收获就开始沤制,充分利用了亚麻收获季节的高温和降雨。沤麻速度快,沤麻时间缩短,降低了生产成本,麻率相对提高0.5-1个百分点,纤维强度增加1.2—2.7kg。此项技术对我国雨露麻的发展具有一定的指导意义。 相似文献
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《Industrial Crops and Products》2007,25(1):8-16
Development of a flax (Linum usitatissimum L.) industry in North America is desired to supply a domestic source of clean, consistent quality textile fiber for blending with cotton. The objective of this work was to evaluate portions of traditional cotton gin equipment (extractor feeder and lint cleaner) and the “50-g cotton-spinning test (CST)” for flax. Dust was collected on an area sampler in an isolated card room to evaluate dust potential during textile pilot plant processing. Fibers retted by diverse means were cleaned on two separate portions of Continental Eagle's pilot plant cotton gin stand, the Super 96 Feeder and the 24D lint cleaner. Fibers separated and removed from flax stalks by these gin sections were compared against the standard ‘unified line’ processing technique of the USDA Flax Pilot Plant. Test yarns were then made in a CST with cotton and flax blends to provide an indirect measurement of fiber properties that can be related to the retting and gin cleaning processes. The yarns were tested for strength and evenness. Flax fibers that displayed the most favorable properties in the CST were then spun in 23 kg lots in the pilot plant at the following cotton/flax blend ratios: 100/0, 75/25, 50/50, 25/75, and 20/80. With modifications, it appears that portions of a cotton gin stand are able to process adequately small samples of properly retted flax stalks. The CST with minor adjustments provides useful data for ranking and further large-scale flax processing. As expected, it appears that flax fiber can be successfully cleaned on a cotton processing line and that increasing the amount of flax generates additional dust. 相似文献
20.
本文提出了我国亚麻在发展过程中存在的问题，指出了具体差距，品种水平落后和机械程度低等六方面原因是制约我国亚麻原料产业发展的瓶颈。为产业的发展提出了建议，增加科研投入、建立良种繁育基地和发展机械收获等方式是解决产业发展的关键。 相似文献