Physico-chemical characterisation and tensile mechanical properties of Agave americanaL. fibres

In this paper, the physico-chemical and mechanical properties of Agave americana L. fibre are studied to explore the possibilities of using this fibre in textile industry. Three different processings for extracting fibres from the leaf of Agave americana L. plant were investigated: (i) raw fibres manually extracted, (ii) fibres extracted by retting leaves in seawater and (iii) fibres extracted after hydrolysis treatment of the leaves in distilled water. Chemical composition (cellulose, lignin and hemicellulose contents), physical properties (density, fineness and crystallinity) as well as mechanical properties of the resultant fibres were measured. The chemical composition reveals that the Agave americana L. fibre has a cellulose content at the order of 62% which is similar to that of other lignocellulosic fibres. The distilled water extracted fibres developed the highest cellulose content. Lignin content of Agave americana L. fibre is low compared to other natural fibres (2.4%) and seawater-extracted fibres generated the lowest lignin content (2.12%). Fourier transform infrared spectra (FTIR) and x-ray diffractometry of all extracted fibres revealed the same chain conformation. X-ray diffractograms showed that cellulose I is the main crystalline constituent. Concerning physical and mechanical properties, raw fibres were characterised by the lowest density (0.9) and the highest crystallinity (51.2%), they are also stronger and less extensible than the other two fibres. In this paper, we attempt to study the effect of extraction in water on the mechanical and physical properties of Agave americana L. fibres.     

玉米苞叶及其纤维的基本结构与性能

为更好地开发利用玉米苞叶资源,采用数字式织物厚度仪、电子织物强力仪、傅里叶变换红外光谱仪、扫描电子显微镜、Ｘ 射线衍射仪对其进行基本测试。通过测试与分析发现：玉米苞叶厚度及横纵向抗拉强度随苞叶层数由外至内逐渐降低;玉米苞叶主要含有纤维素,半纤维素和木质素;经化学处理后的纤维,其纤维素含量达到４３.７９％,半纤维素和木质素含量有所降低;玉米苞叶表面凹凸不平,有随机分布的孔洞,单纤维横截面形状不规则且内部有大中腔,纵向表面较为光滑平整;玉米苞叶结晶度约为３８.９０％,纤维结晶度为５７.８５％,二者均表现为纤维素Ⅰ的晶体结构。     

Characterization of New Natural Cellulosic Fiber from the Bark of Dichrostachys Cinerea

The increasing environmental awareness has directed attention of the researchers towards the field of natural fiber composites. The aim of this investigation is to understand the physico-chemical properties of fibers extracted from the bark of the Dichrostachys Cinerea (DC) plant. Dichrostachys Cinerea fibers (DCFs) has cellulose (72.4 wt. %), hemicellulose (13.08 wt. %), lignin (16.89 wt. %), density (1240 kg/m³), crystallinity index (57.82%), and tensile strength (873 ± 14 MPa). Besides the cellulose degradation of DCFs at 359.3° vide by the thermo-gravimetric analysis and chemical groups are identified by Fourier transform analysis. Eventually the characterization results of DCFs strongly show the possibility of reinforcement in polymer matrices.     

剑麻载银复合抗菌纤维的制备及其性能

以自制纳米银粒子为抗菌剂,基于膜自组装原理,采用Nβ--(氨乙基)-γ-氨丙基甲基二甲氧基硅烷偶联剂(YDH602)为架桥剂,制备了键合型载银剑麻复合抗菌纤维。以纤维载银量为指标,考察了纳米银溶胶质量浓度、反应时间、pH值对载银效果的影响。利用TEM、紫外光谱仪、SEM、X-射线能谱仪等对纳米银粒子和剑麻抗菌纤维结构进行了表征。结果表明,所制备的剑麻抗菌纤维载银量较多,并且分布比较均匀,在48 h内,银释放量为0.17%,说明银与剑麻的结合能力较强,并且会持续稳定地释放出银。此外,载银剑麻纤维对金黄色葡萄球菌和肺炎克雷伯菌的抗菌效果较好。     

水稻秸秆纤维素纳米晶须的制备及其表征

为开发水稻秸秆的高附加值应用,采用2,2,6,6-四甲基哌啶-氮-氧化物（TEMPO）体系,以水稻秸秆为原料制备纤维素纳米晶须,并采用傅里叶变换红外光谱仪、扫描电子显微镜、X射线衍射仪等对其进行表征分析。研究结果表明：水稻秸秆主要含有纤维素、半纤维素和木质素,经化学处理后纤维素含量显著提高,而半纤维素和木质素含量有所降低;水稻秸秆横截面呈多孔状,内部及表面均随机分布着大小不等的球状颗粒;化学处理部分去除了非纤维素物质,纤维表面变得相对较光滑;冷冻干燥后的纤维素纳米晶须交织成多层网状,直径为10~25nm,长度为200~400nm;水稻秸秆及其纤维与纤维素纳米晶须的结晶度分别为29.76%,30.28%和40.71%,三者均表现为纤维素Ⅰ的晶体结构。     

载药再生细菌纤维素纤维的制备及其表征

为获得一种具有优良生物相容性,能够用于伤口敷料的纤维材料,以细菌纤维素为原料,以氯化锂/二甲基乙酰胺为溶剂体系制备纺丝液,以水为凝固浴,采用湿法纺丝技术制备再生细菌纤维素纤维,进而以环丙沙星为模型药物对再生细菌纤维素纤维进行载药整理,制得一种可用于伤口敷料的载药纤维。通过X射线衍射、力学性能、载药性、释药性等测试对再生细菌纤维素纤维进行表征。结果表明:纤维直径约为40μm,表面呈沟槽结构,力学强度可达2.5 c N/dtex;细菌纤维素再生后,晶型发生了改变,从纤维素Ⅰ型转化成纤维素Ⅱ型,且结晶度从66.3%降低至36.2%;载药和释药结果显示,再生细菌纤维素纤维在碱性条件下载药量最高,载药纤维在酸性条件下释药量最高。     

Characterization of natural cellulosic fiber from Epipremnum aureum stem

The natural fiber Epipremnum aureum was extracted from its plant. E. aureum fibers (EAFs) were investigated by chemical analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and single fiber tensile test. Chemical analysis, FTIR, and X-ray analysis evidenced that these fibers has 66.34% cellulose content with crystallinity index of 49.33%. The thermogravimetric analysis reveals that EAFs can thermally withstand temperatures until 328.9°C. The morphology of the EAFs was observed by scanning electron microscope. It was established that the fiber can be utilized as reinforcement in polymer composites.     

聚乳酸纤维/棉混纺纱的力学性能研究

测试了聚乳酸纤维的物理性能,并通过聚乳酸纤维／棉混纺实验,研究了聚乳酸纤维／棉混纺纱的力学性能与聚乳酸纤维含量的变化关系。     

A new study on characterization of Pithecellobium dulce fiber as composite reinforcement for light-weight applications

ABSTRACT

A bio-fiber, Pithecellobium dulce is abundantly available in all over the world. It has a higher cellulose content (75.15 ± 0.26 wt.%) and low density (865 ± 26 kg/m³). To acquire fundamental knowledge about Pithecellobium dulce Fibers (PDFs), its physicochemical, crystalline, tensile, and morphological properties were examined and compared with other plant fibers. The chemical functional groups and crystallinity index (49.2 ± 2.45%) of the PDFs were obtained via Fourier transform-infrared analysis and X-ray diffraction, respectively. The Thermogravimetric analysis results of PDFs exhibit thermal stability up to 170°C. The surface morphology of PDF was analyzed by scanning electron microscopy. The attained results conclude that PDFs are appropriate fibers for acting as reinforcement in manufacturing of green composite product.     

牛奶蛋白纤维的结构与性能

利用扫描电子显微镜观察了牛奶蛋白纤维的形态结构。结果表明,牛奶蛋白纤维是异形纤维,截面上有微孔,表面有凹槽;对牛奶蛋白纤维的X-射线衍射分析显示聚乙烯醇分子规则排列构成结晶部分,牛奶蛋白形成无定形区;测试和分析了牛奶蛋白纤维的吸湿、拉伸、摩擦等性能,结果表明牛奶蛋白纤维是集蚕丝和合成纤维优良性能于一身的纺织新材料。     

Extraction and Characterization of Novel Natural Cellulosic Fibers from Pigeon Pea Plant

ABSTRACT

This study is mainly focused on the extraction and characterization of the lingo-cellulosic fibers from the Pigeon Pea plant. The chemical components of the fibers such as cellulose content (55.03%), lignin (18.32%), wax content (2.38%), moisture content (8.13%), and density (1.7389 g cc^?1) were identified. Functional groups present in the fibers were obtained by infrared spectroscopy. By using X-ray diffraction analysis, Crystallinity Index is found to be 68% and thermogravimetric analysis showed that thermal degradation of the fiber begins at 225°C.The results suggest that the Pigeon pea fibers can be used as reinforcement in polymer-matrix composites.     

Study of the Mechanical Properties of Fibers Extracted from Tunisian Agave americana L.

Agave americana L. fibers, the most abundant variety in Tunisia, have a quite important textile potential. This potential is demonstrated by studying the extraction of these fibers from leaves, their physical properties such us fineness or density and their mechanical behavior in tensile tests. In this work, results of a mechanical behavior study of fibers extracted from the Agave americana L. plant are presented. These results deal with the principal and mechanical characteristics of these fibers which are the strain at break, the elasticity modulus and the rupture facture. These results permitted to situate these fibers, compared to the other textile fibers, as materials that can be used in technical applications such as reinforcing composites or geotextile. In order to understand the mechanical properties of these fibers, a correlation study between the properties already cited and the fine structure was done. The obtained results showed that the mechanical properties of Agave americana L. fibers are closely related to the individual fibers deformations and to the natural matrix (lignin and gums) that are linked to these elementary fibers.     

菠萝叶纤维化学脱胶过程中理化性能变化规律

采用纤维组分测定、单色荧光显微成像系统、傅里叶红外光谱(FT-IR)、X射线衍射(XRD)、拉伸性能测试等手段表征菠萝叶纤维在化学脱胶过程中组成、结构与力学性能的变化规律。结果表明:在化学脱胶过程中,菠萝叶纤维成分变化较大,纤维素含量由60.21%提高至80.09%,半纤维素含量由16.62%降低至7.68%,木质素含量由10.68%降低至1.03%,果胶含量由3.30%降低至1.13%;半纤维素和果胶在预酸、碱煮后发生了剧烈降解,大部分木质素还需漂白后方能去除;纤维细度逐渐变小,表面变得光滑,沟槽逐渐明显,分离度增加,均匀性提高;纤维素晶型保持不变,均属于Ⅰ型纤维素,但相对结晶度逐渐升高;纤维断裂强力和断裂强度虽然有所降低,但可满足后续纺纱要求。     

响应面分析法优化微波改善小麦蛋白纤维力学性能的工艺

以谷朊粉为原料,分别分离麦谷蛋白和麦醇溶蛋白后,按麦谷蛋白∶醇溶蛋白（w/w）=1∶1,蛋白浓度15%,凝固时间20 min进行湿法纺丝,并通过微波进行改性以提高蛋白纤维的力学性能并优化工艺条件。在单因素实验的基础上,选取微波功率、微波时间和p H为自变量,以断裂强度和断裂伸长率为响应值,利用响应面优化方法（RSM）中的Box-Behnken方法研究自变量及其交互作用对响应值的影响。得到的最优条件为:微波功率为206 W,微波时间为3 min,p H为8,所得的小麦蛋白纤维的断裂强度为0.69 c N/dtex,断裂伸长率为23.37%。与空白对照组相比,断裂强度增加了19%,断裂伸长率增加了302.43%。因此,微波可以明显提高小麦蛋白纤维的力学性能。      

基于HVI数据棉纤维品质指数模型的构建

为用棉纤维性能指标预测成纱强度,运用路径分析法研究了原棉性能与成纱强度的关系,确定了影响成纱强度的关键指标为棉纤维上半部平均长度、纤维断裂比强度、马克隆值等,并在国内外原棉性能与成纱强度研究的基础上,选择出拟合效果较好的纤维品质指数模型IFQI,进一步提出了新的纤维品质指数模型FQI,再运用高维数据拟合法将IFQI模型改进为IFQIM。经过检验证明3个模型的预测精度都很高,拟合优度好。3个模型都具有自变量少、结构简洁、机制性强、通用性好的特点,可综合反映原棉的品质并预测成纱强度。     

Tencel纤维与粘胶纤维的湿加工性能比较

通过打浆实验，研究探讨了Tencel纤维与粘胶纤维的湿加工性能，结果表明：Tencel纤维由于其良好的刚性、湿强度及易于原纤化的特征，使其具有良好的湿加工性能，从而为Tencel纤维在特种纸领域的开发应用提供理论依据。     

竹原纤维的分级提取及其性能

为探究不同竹龄及不同取材部位竹原纤维性能的变异规律,以不同竹龄、不同部位的慈竹为原料,采用物理化学结合的方法提取竹原纤维,并分别测定竹原纤维的化学组成、纤维的表面形貌、纤维的密度、吸湿性能、拉伸强度。结果表明：相同部位竹原纤维,随竹龄的增加,纤维的密度先增大后减小,纤维的回潮率先减小后增大;相同竹龄竹原纤维,随着距地高度的增加,纤维密度增加,回潮率先稍有降低后升高。3年生慈竹梢部纤维密度最大,为1.70 /cm3,4年生的基部纤维密度最小,为1.51 g/cm3。3年生慈竹中部纤维回潮率最低,为12.94%,其不同部位竹原纤维拉伸强度较为稳定,4年生中部竹原纤维拉伸强度最大,为787.42MPa。     

内切纤维素酶预处理对漂白马尾松纤维形态和结构的影响

针对制备纤维素微纤丝(CMF)所需要高能耗的问题,采用内切纤维素酶对漂白马尾松纤维进行预处理,研究内切纤维素酶预处理过程中,纤维形态、纤维素聚集态和纤维性能所发生的变化。结果表明,内切纤维素酶优先作用于纤维表面,不会对纤维产生明显的起皮、剥皮现象,但是对纤维的切断作用较强,导致内切纤维素酶用量增大时,纤维的平均长度逐渐减小,宽度增加,保水值和Zeta电位逐渐下降,打浆度在酶预处理初期略有下降,之后不断增大;内切纤维素酶主要作用于纤维素的无定形区,使纤维素的结晶度增大,最后在80%~82%之间波动;若要纤维素完全发生水解,还需外切纤维素酶和纤维二糖酶的协同作用。