云南野生火草纤维及其绒网的结构与性能

火草是少数民族非物质文化遗产火草纺织技艺中的古老纺织原料,为了对火草纤维进行系统研究并实现在纺织领域的推广应用,选取云南野生火草,通过手工方式从其叶片背部剥离火草纤维绒网。通过实验表征了火草纤维及其绒网的基本结构和性能。结果表明:火草纤维直径在1.05~5.76 μm之间,为超细纤维,其纵向形态为特征性的带状转曲,表面有褶纹沟槽,横截面呈不规则腰圆形带中腔结构;纤维主要成分为纤维素和半纤维素,结晶度为55.52%,具有较好的耐热性,热分解温度为240 ℃;纤维中脂蜡质含量为6%,与水的接触角约为129.5°,有较好的疏水能力,回潮率为11.69%,含水率为10.47%,与棉纤维相比较高;火草纤维常温下耐酸碱性好,纤维水萃取液的pH值为7.23,对人体皮肤友好。     

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.     

Influence of low-temperature plasma treatment on properties of ramie fibers

In this study, ramie fibers were treated under various low-temperature plasma conditions such as different output powers (100, 150, 200, 250, and 300 W) and irradiation times (1, 1.5, 2, 2.5, and 3 min). The effects on fiber surface morphology, contact angle, friction and tensile properties were investigated. The results showed that properties of ramie fibers changed significantly after low-temperature plasma treatment. Compared with the untreated fibers, surface free energy increased 117.0 and 122.9%, friction coefficient improved 10.7 and 13.4% after 1 min-300 W and 3 min-100 W treatment. However, with the higher output power and the prolonged treatment time, low-temperature plasma treatment may cause damage to the tensile property of ramie fiber. Scanning electron microscopy showed that pectin and impurities covering of fibers were removed after low-temperature plasma treatment and alkali treatment, and the surface of ramie fiber was etched by low-temperature plasma treatment. Based on the analysis of experimental results, three groups (1 min-100 W, 2 min-150 W, and 3 min-200 W) were chosen as the following treatment process and compared with alkali treatment. It was found that properties of ramie fibers had more significant change after low-temperature plasma treatment.     

莲纤维的物理性能

为了解莲纤维的基本物理性能,为莲纤维织物的开发提供理论参考,对莲纤维的密度、线密度和回潮率等基本物理性能进行测试。研究表明:莲纤维的密度为1.1848 g/cm3,远比棉、苎麻及羊毛的密度小,与蚕丝、腈纶接近;莲纤维的线密度为1.55 dtex,远小于苎麻、蚕丝,与棉纤维及棉型化纤的线密度较接近,说明莲纤维较细,有利于成纱强力和条干均匀度,可纺高支纱;莲纤维回潮率为12.32%,比棉、蚕丝高,比羊毛、粘胶要低,与苎麻接近,说明莲纤维具有很好的吸湿性。     

Characterization of cellulosic fibers from Morus alba L. stem

The chemical microstructural, physical, and thermal properties of the Morus alba L. stem fibers (MAFs) are described for the first time in this work. By analyzing the results of chemical composition, it was observed that the cellulose content of the stem of MAFs is an acceptable value when compared with other fibers and showed better results. Due to their lightweight (1316 kg/m³) and the presence of high cellulose content (58.65%) with very little amount of wax (0.56%), they provide good bonding properties. In addition, analyzing the results of X-ray diffraction and Fourier transform infrared spectroscopy, we observe a degree of crystallinity of 62.06%, which is closely associated with the presence of crystalline cellulose, while the other components are amorphous. The diameter of the extracted cellulosic fibers was in the range 6–20 µm. Moreover, it was possible to identify the degradation step of each primary component of lignocellulosic fiber and to observe that it is thermally stable up to 216°C. The characterization results show that the MAF is a better replacement material for synthetic fibers because of its significant physical, chemical, and thermal properties.     

Contact thermal post-treatment of oriented strandboard to improve dimensional stability: A preliminary study

The oriented strandboard (OSB) has less dimensional stability than plywood, but they are competitive panels and have been used for similar ends. The wood-water relation variables, such as thickness swelling and water absorption, express this OSB dimensional instability and can be explained by two main factors: wood hygroscopicity and imposed hot-pressing stresses. The objective of this present paper was to propose a thermal post-treatment as a method to improve OSB dimensional stability by decreasing wood hygroscopicity and releasing hot-pressing stress. OSB panels from Pinus taedawood were produced in laboratory, and their characteristics were: single layer, 0.8 g/cm³; 8% phenolic resin and without wax. The OSB panels were treated in a laboratory press at 250 °C for about 4, 7 and 10 minutes. The wood-water relation variables, thickness swelling (TS), water absorption (WA), equilibrium moisture content (EMC) and springback or permanent thickness swelling (PTS) were determined and compared with untreated panels. The results showed that the proposed thermal treatment was effective to reduce TS, EMC and PTS, but didn’t affect WA which was affected by panel density reduction. The longer the treatment the higher the dimensional stability, and panel weight loss could be used as predictive variable for the efficiency of the treatment.     

应用聚类统计分析的棉花异纤图形检测算法

在棉纺企业原棉异性纤维剔除工艺过程中,异性纤维种类及特征多样,难以构造统一的识别模型,为此,提出了一种基于聚类统计分析的棉花异性纤维图形检测算法。通过获取原棉纤维及异性纤维在RGB颜色模型空间的各分量值,进行数值聚类统计分析,采用RGB彩色图像阈值聚类统计分类的方法将获取的图片信息分为3类,进而判断有无异性纤维,再经过形态学等预处理修缮图像,对棉花中异性纤维的特征进行提取,较准确地得到异性纤维的面积、质心坐标和周长等参数,为异性纤维的清除提供条件。实验结果表明,该算法能较准确地识别异性纤维。     

棉花异性纤维的危害和预防

棉花是纺织品的主要原料,我国是一个纺织品出口大国,纺织品的发展推动了我国经济社会的发展,但是,当前我国纺织品出现棉花含异性纤维的问题,异性纤维对人们造成极大的伤害,因此,本文首先阐述棉花、化纤等原材料对纺织品的影响和作用,针对棉花异性纤维的危害,提出相应的预防措施。     

Polypyrrole-Coated Conductive Cotton Prepared by Laccase

Conductive cotton fabric was prepared using laccase as catalytic agent, pyrrole as electric monomer and paratoluene sulfonic acid sodium salt as dopant. The electric resistance of the prepared conductive cotton fabric was 1.22 × 10⁷ Ω compared to 3.11 × 10¹¹ Ω of the original cotton fabric. The abrasion test indicated that polypyrrole was well integrated with the cotton fibers. The conductive cotton fabric also had good antistatic performance and good UV shield capability at 280–400 nm compared to the original cotton fabric. Moreover, the coating of polypyrrole improved the thermo-decomposition behavior of cotton fabrics. Nevertheless, the prepared conductive cotton fabric preserved the same breaking strength as the original cotton fabrics. Compared with original cotton, conductive cotton showed lower gas permeability.     

The removal of impurities from gray cotton fabric by atmospheric pressure plasma treatment and its characterization using ATR-FTIR spectroscopy

Gray cotton fabric shows hydrophobic characteristics due to presence of non-cellulosic impurities in outermost layers of cotton fiber. In the present study, atmospheric pressure plasma treatment for the removal of the non-cellulosic impurities from gray cotton fabric is investigated. Gray cotton fabric is treated with air dielectric barrier discharge at different time interval, and characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM). Different species formed in plasma are identified using optical emission spectroscopy. The results clearly show that the plasma treatment improves wettability of gray cotton which is due to the removal of non-cellulosic impurities and due to the formation of polar carboxylate group. Removal of wax after plasma treatment is clearly reflected in ATR-FTIR spectra as disappearance of symmetric and asymmetric stretching of alkyl group at 2852.24 and 2917.81?cm^?1. Further, ATR-FTIR spectroscopy provides a fast and satisfactory assessment of removal of impurities from cotton surface when untreated and plasma-treated cotton fabric is exposed to HCl vapor and subsequently spectra are collected. We observed a strong carboxyl peak is induced at 1749?cm^?1 in case of untreated cotton. While for plasma-treated cotton fabrics substantial variation in the intensity of 1641 and 1749?cm^?1 peak is observed with increase in plasma treatment time. The morphological changes observed by SEM are in accordance with ATR-FTIR results. The results are compared with conventionally (alkaline scouring) treated cotton fabric. The study reveals that atmospheric pressure plasma has potential to become dry and environment friendly process to improve wettability of gray cotton fabric.     

Effect of oil type, temperature and time on moisture properties of hot oil-treated wood

This paper focuses on the moisture properties of wood treated in palm oil-, soy oil- and slack wax for different processing times and temperatures. Also, the relative importance of oil uptake and thermal modification on the wood moisture properties is investigated. Slack wax was better than palm oil or soy oil in improving the moisture performance of thermally treated wood, and treatment at 220 °C was superior to treatment at 200 °C, with 4 h being generally better than 2 h treatment. Water absorption in samples treated with wax at 100 °C or 160 °C was similar to that in samples treated at high temperatures while improved anti-shrink efficiencies (ASE) and lower hygroscopicities occurred only for the high temperature treatments. Chloroform extracted samples treated at high temperature with palm oil or soy oil had relatively similar hygroscopicity and ASE properties compared to unextracted samples, but had greatly increased water absorption properties. These results confirm that chemical reactions in wood resulting from the heat treatment account for the main improvements of wood properties in reduced hygroscopicity and improved dimensional stability, while the oil absorbed by wood reduces the rate of water absorption.     

Effectiveness of Alkali and Sodium Bicarbonate Treatments on Sugar Palm Fiber: Mechanical,Thermal, and Chemical Investigations

ABSTRACT

Sugar palm fiber (SPF) as one of the attractive natural fibers to reinforce matrix is gaining attention. This is largely due to its similar properties when compared with other established natural fibers. The aim of this study is to investigate the effectiveness of sodium bicarbonate as a treatment chemical for SPF in comparison with established alkaline treatment. Both treated and untreated fibers were characterized and it was found that the treated fiber shows an increase in crystallinity, thermal stability, and surface’s roughness when compared with the untreated. Among the two different treatments, SPF treated with alkali has an initial decomposition temperature of 255.47°C, while sodium bicarbonate treated and untreated fibers have 250.19°C and 246.76°C, respectively. In both cases, the thermal stability of the fiber was improved. Also, as revealed by the X-ray diffraction (XRD) analysis, the crystallinity index of SPF treated with alkali and sodium bicarbonate increased by 18.43% and 13.60%, respectively, when compared with untreated fiber. In conclusion, the investigation proved that treatment with the sodium bicarbonate has a significant effect on the physicochemical properties of SPF and the chemical could be an alternative chemical for treating other cellulose fibers.     

Characterization of Untreated and Alkaline-Treated Salago Fibers (Genus Wikstroemia Spp.)

Salago fiber (genus wikstroemia spp.) is a bast natural fiber native of the Philippines. This fiber is found all over this country and has various applications, e.g. as handmade paper, currency paper, or bank notes. In this study, untreated and 5 wt% NaOH-treated Salago fibers was characterized chemically, physically, thermally, and morphologically for the first time. It was found that the treatment increases density and improves the mechanical properties of the fiber. Fourier transform infrared spectroscopy analysis revealed stretching O–H and C–H alkane groups at 3330 cm^?1 and 2918 cm^?1 respectively and confirmed lignin reduction for the treated fiber. Thermogravimetric analysis showed that treated fibers possessed greater thermal stability. Scanning electron micrographs used to measure fiber diameters showed the rugged surfaces of untreated fibers and the glossier but more distorted surfaces of the treated ones.     

Physical Characterization of Wax/Oil Crystalline Networks

The objective of this research was to evaluate the physical properties of different types of wax/oil systems. Olive (OO), corn (CO), soybean (SBO), sunflower (SFO), safflower (SAFO), and canola (CAO) oils were mixed with sunflower oil wax (SFOW), paraffin wax (PW), and beeswax (BW) at different concentrations (1% to 10%). Results from this study show that the physical properties of wax/oil systems is affected not only by the concentration and type of wax used, but also by the type of oil used. In general, wax/oil systems formulated with SFOW generated crystalline networks with high enthalpies (1 to 22 J/g) and high G ′ values (2 to 6 × 10⁶ Pa) compared with the values obtained for BW and PW. SFOW crystalline networks were characterized by needle‐like crystals independently of the wax concentrations and type of oil used. BW crystalline networks, however, were characterized by different crystal morphologies (needle‐like or spherulites) depending on the wax concentration and type of oil used. PW samples were characterized by a crystalline network formed by needle‐ and platelet‐like crystals. Enthalpy values of BW and PW samples were similar (0.3 to 20 J/g), but BW samples resulted in significantly higher (P < 0.05) G ′ values in the 5% and 10% samples with values of 3.9 × 10⁶ and 6.1 × 10⁵ Pa for 10% BW and PW, respectively.     

Scope of Sustainable Pretreatment of Cotton Knit Fabric Avoiding Major Chemicals

ABSTRACT

The present effort attempted to avoid basic chemicals, namely NaOH and H₂O₂ in scouring and bleaching of cotton knit fabric in order to reduce the chemical load and processing cycles without compromise of dyeing performance. Single jersey single lacoste cotton knit fabrics treated with detergent and wetting agent at 120°C temperature for 20 minutes revealed 5.8% weight loss. FTIR graphical data validated the weakening and moving out of characteristic bands of wax and pectin-based cotton impurities in the region of 1740–1200 cm^?1. The color differences of 1.5% and 1% dyed samples confirmed pass value (CMC ΔE ≤ 1) when treated at 105°C temperature for 20 minutes. The grading for color fastness to wash, perspiration, rubbing and light was 4–5 to 5. No deterioration in strength and morphological changes were experienced for the treated samples.     

棉秆皮纤维的草酸软化处理工艺

改进棉秆皮纤维在纺织中的应用,利用草酸对棉秆皮纤维进行软化处理。采用正交实验,并结合直观分析与方差分析方法,得到实验因素对棉秆皮纤维可挠度的影响程度以及棉秆皮纤维软化处理的最佳工艺参数;在最佳工艺参数下,棉秆皮纤维可挠度为2.55 T/(m?tex)、断裂强度为3.13cN/dtex;在显著水平α=0.01,焙烘温度对处理后棉秆皮纤维可挠度有显著影响。通过D/MAX-2400型X射线衍射分析仪对棉秆皮纤维测试与相关分析计算,得到软化处理后棉秆皮纤维的结晶度为64.9%,小于未处理棉秆皮纤维的结晶度。     

Research on fiber distribution in front draft zone of super high draft ring spinning based on cut-middles method

A super draft ring spinning machine was designed to spin high-count cotton yarns. It was equipped with four-line draft system (FLDS) and four aprons. For yarns spun on FLDS, it often occurs that yarn unevenness increased compared with three-line draft system (TLDS). In the paper, by cut-middles method, the fiber distribution in front draft zone of FLDS draft system was studied, and corresponding yarn qualities were analyzed. First, comparison analysis of yarn quality between FLDS and TLDS was presented. Cotton yarns of 9.7 and 7.3 tex were spun by TLDS and FLDS ring spinning machine, respectively. The results shows that for 9.7 tex cotton yarn, slower fibers in yarns spun on FLDS are more than that in yarns spun on TLDS. For FLDS, the friction field at the back of front draft zone is stronger, which improves yarn evenness. However, for 7.3 tex cotton yarn, accelerated point of fibers on FLDS is nearer to nipper bite of front roller than that on TLDS. Thus, evenness of yarns spun on FLDS is better. Then, 4.9 tex cotton yarn was taken as an example, and they were spun by four kinds of draft distributions on FLDS. The results indicate that for 4.9 tex cotton yarns spun by 64.1 × 1.60 × 1.15, slower fibers at the back of front draft zone are mostly found. And accelerated point of fibers is nearest to nipper bite of front roller. Therefore, 4.9 tex cotton yarns spun by 64.1 × 1.60 × 1.15 have best yarn evenness.     

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.     

Effects of alkalization on the properties of Ensete ventricosum plant fibre

Ensete ventricosum (EV) fibre is a lignocellulosic plant fibre hitherto, to the best of our knowledge, unexplored in terms of its response to alkali treatment at room temperature. The chemical compositions as well as physical and tensile properties of this fibre were evaluated after alkali treatment (in 2–15%w/v NaOH at 23 ± 2 °C for 1 h). Effects of alkali concentration on fibre properties were analysed and compared with that of untreated fibres. EV fibres treated with alkali solutions between 2 and 10% (w/v NaOH) exhibited all round improvement in physical, morphological, tensile, structural and thermal properties as compared to that of untreated EV fibres. Unlike the cellulose content, hemicellulose content of alkalized fibres decreased substantially with increase in alkali concentration. The 10% NaOH treated fibres showed the highest improvement in tenacity (9.1 gf/den), crystallinity index (71%) and other properties. Changes in fibre properties were further confirmed by SEM, XRD and TGA.