Silk degumming using microwave irradiation as an environmentally friendly surface modification method

Degumming is a surface modification process of natural fibers such as silk. In this paper, the feasibility of degumming of Persian silk by microwave irradiation as an environmentally friendly surface modification technique was investigated. The physical properties of the degummed silk were investigated. The effectiveness of parameters such as microwave irradiation time, surfactant, soap, and degumming time on silk degumming were studied. The evaluation of the data was carried out through the measurement of the weight loss, strength, and elongation of the samples. The scanning electron microscope images were obtained for degummed silk samples. The findings of this research support the potential production of new environmentally friendly textile fibers using microwave irradiation.     

苎麻化学脱胶废水处理技术的研究进展

概述了苎麻脱胶废水处理方法的研究现状和最新进展，尤其是在物化法(光催化氧化法)、生物法(分步厌氧、水解酸化和SBR法)及生物物化学联合法(生化一光催化氧化法)中的新技术和研究现状，对此类废水的处理有重要的理论意义和实际意义。     

苎麻主要品质性状相互关系的研究

苎麻纤维细度、细度均匀度、断裂强力、强度、伸长率及结晶度等品质性状是影响苎麻品质及其可纺性的几项主要因素。本文对30个苎麻品种的主要品质性状进行了研究,并利用断裂强力与纤维直径之间的极显著相关性,建立断裂强力依直径的回归方程：y=-1．887＋1．756x。     

麻纤维厌氧生物脱胶系统的脱胶特性研究

基于具有自主知识产权的麻纤维厌氧生物脱胶系统,对苎麻、剑麻、大麻和棕榈麻进行厌氧脱胶处理。结果表明:该系统运行过程中pH值稳定在7.2左右,化学需氧量(COD)在327 mg/L以下,氨氮质量浓度在5.2 mg/L以下,能实现近零排放;试验参数条件下苎麻脱胶效果优于剑麻、大麻和棕榈麻:苎麻纤维残胶率可达1.32%(低于化学脱胶),剑麻、大麻和棕榈麻残胶率分别为16.03%、20.13%、35.49%;各纤维强力指标能够达到传统化学脱胶法水平,其中苎麻的各项指标满足《苎麻精干麻》(GB/T 20793-2015)的一等水平。     

Low-temperature pyrolysis on jute fibers as a thermochemical modification method

Low-temperature pyrolysis up to 200, 250, 300 °C was conducted in order to remove non-cellulosic compounds without damaging the structure of the cellulose in jute fibers. The chemical, morphological, and mechanical aspects of prepared low-temperature pyrolyzed jute fibers were investigated by Fourier transform infrared (FTIR) spectroscopy, the wettability test in water/dichloromethane system, moisture content measurement, X-ray diffraction (XRD) analysis, scanning electron microscope (SEM), and tensile test using universal testing machine (UTM). It was confirmed that hydrophilic compounds including absorbed water, low molecular weight compounds such as waxes, hemicellulose, and lignin were largely removed from the fibers. Increasing amounts of non-cellulosic compounds were removed as the maximum pyrolysis temperature was increased. The degree of hydrophilic nature of jute fibers were reduced by low-temperature pyrolysis and thus water absorptivity of pyrolyzed jute fibers was reduced as maximum pyrolysis temperature increased. Furthermore, XRD analysis and morphological studies by SEM indicated that the crystalline structure of native cellulose was rarely damaged after pyrolysis up to 300 °C. In case of mechanical properties, breaking tenacity and breaking strain of the fibers decreased with increasing maximum pyrolysis temperatures because flaws formed on the surface of pyrolyzed jute fibers acted as weak-links. In agreement with predictions made according to Weibull’s weakest-link theory, it was found that shortened pyrolyzed jute fibers could have higher breaking tenacities compared with raw jute fibers of the same length. In addition, the compatibility with hydrophobic matrix was investigated by the mechanical properties of polypropylene (PP) reinforced with jute fibers. Consequently, it was hypothesized that low-temperature pyrolysis could be used to process raw jute fibers for use as short fiber reinforcements in fiber-polymer systems or be a simple and effective pretreatment method for a wide range of further chemical treatments.     

Investigation on air texturing process for diacetate blending with polyester filaments

Influences of processing parameters on tensile property, stability and bulk of core-and-effect air textured yarns of diacetate and polyester filaments are mainly examined in this paper. When the air pressure is raised, the tenacity and breaking elongation of textured yarns are reduced, Instability I and II tend to decrease at first and then increase, the core bulk declines markedly at first and then changes slowly, whereas the overall bulk changes little at first and then goes up greatly. With increase in texturing speed, the yarn tenacity and breaking elongation both drop initially then begin to increase, the core bulk and overall bulk are almost linearly increased, while the yarn instability changes with an unclear trend. When the winding underfeed ratio is increased, the yarn tenacity, breaking elongation and core bulk are reduced, but the yarn stability is slightly improved. The wetting of the core component produces higher tenacity, breaking elongation, instability and bulk, compared with that of the effect component or that of both, but the difference is insignificant.     

微波辅助加热及高温高压脱胶对剑麻纤维结构的影响

采用微波辅助加热、高温高压蒸煮法,以氢氧化钠为脱胶剂,对剑麻叶片进行脱胶,将所得的纤维进行扫描电镜观察纤维结构。结果表明,微波辅助加热脱胶所得的剑麻纤维较为坚韧,强力较大;高温高压蒸煮法所得的纤维较硬而脆。扫描电镜照片显示,微波辅助加热脱胶的纤维表面较为光滑;高温高压蒸煮法所得的较为粗糙。     

Environmentally benign scouring of wool fibers using mesophile acidic lipase

Surfaces of raw wool fibers possess high amounts of greasy substances that need to be removed prior to further processing. Acidic lipases using Bacillus licheniformis (MTCC 2618) were produced with the optimum activity levels closer to the room temperature. Scouring of wool fibers using mesophile acidic lipase has been attempted, in the present work, as an alternative to the existing alkaline treatment and the samples were assessed in terms of weight loss, moisture regain, tenacity, elongation, surface appearance, and friction of the fibers. The lipase scoured wool fibers showed moisture regain and weight loss values comparable to that of alkaline treatment, with lower static and dynamic frictional coefficients. Higher tenacity and elongation values were observed in the lipase scoured fibers compared to the alkaline scoured samples and clear appearance of the surface, compared to the raw wool fibers, was also observed in the lipase scoured samples.     

Effect of fibre cross-sectional shape on the properties of POY continuous filaments yarns

There are various structural parameters (number of filament, cross-sectional shape, linear density, etc.) determined during the production of synthetic fibre and these parameters influence product features. Among these parameters, cross-sectional shape of fibres has a significant importance. Desired features can be added to the products by varying the cross-sectional shape and in this way; new products with improved features or with high added value can be produced. As a consequence, studies on this subject have increased recently. In this study, the effects of different cross-sectional shapes and yarn linear density on the features of polyester partially oriented yarn (POY) have been investigated. Five different cross-sectional shapes named round, trilobal, tetra, hexsa and octolobal and two different linear densities have been used in the study. Tenacity-elongation and unevenness tests have been applied onto yarns. As a result of the study, it was seen that round, tetra and octolobal cross-sectional shapes lead to production of yarn with high tenacity and breaking elongation while trilobal and hexsa leads to production of yarn with low tenacity. In addition, due to its deep-channelled structure, hexsa crosssectional shape led to POY yarn structure with a high unevenness rate. It was also seen that an increase in the rate of linear density decreased the tenacity and breaking elongation rates of yarn and reduced POY unevenness.     

Effect of peroxide and softness modification on properties of ramie fiber

Ramie fiber is one of the natural cellulose fibers that have undergone rapid development due to its good performance. This study confirmed that hydrogen peroxide and isopropyl alcohol can be used as very efficient agents for simultaneous removal of non-cellulosic substances and improvement of ramie fiber properties. The factors influencing the properties of modified fiber with combined chemicals were investigated. Optimum treatment conditions were achieved at 85 °C, 60 min, pH 11.0, hydrogen peroxide concentration 7 %, and isopropyl alcohol concentration 4 %. SEM, XRD, and FT-IR were used to elucidate the effects of preparation and modification. Results showed that fiber preparation and chemical modification process in the same bath solution could successfully remove most of the gummy materials. The treated fibers demonstrated improved softness, elongation, and fineness properties as compared to the alkali or peroxide method.     

不同苎麻品种纤维物理性能的差异及相关性的初步研究

比较研究107个不同苎麻品种纤维物理性能，结果表明：单株原麻干重、有效株、断裂功、纤维支数、断裂强力(强度)变异系数较大；单株原麻干重与纤维支数极显著负相关，与断裂强力(强度)显著正相关，与株高极显著正相关；纤维支数与断裂强力(强度)极显著负相关，与断裂伸长(伸长率)极显著负相关；纤维断裂强度(强度)与断裂伸长(伸长率)呈极显著正相关，与断裂功极显著正相关。     

我国苎麻生产的问题与发展建议

本文从环境保护、生产成本、技术研发、行业联系及政策扶持等方面探讨了我国当前苎麻生产的形势与问题,从天然纤维需求、苎麻特性及农业资源区划等角度分析了苎麻产业的发展前景,并从种植区域布局、机械化生产、清洁化脱胶、多用途及政策等方面重点提出了推动该产业发展的建议。     

不同脱胶方法加工罗布麻精干麻品质比较

用生物化学联合脱胶与纯化学脱胶两种脱胶方法对罗布麻进行了脱胶试验，并利用数学的方法对两种脱胶方法得到的精干麻的各项指标进行了综合评比，结果表明，使用生物化学联合脱胶得到的精干麻的综合指标为K1=0．62609，使用纯化学脱胶所得到的精干麻的综合指标为K2=0．42164，前者优于后者。     

苎麻脱胶菌种的特性研究

本文对苎麻脱胶菌种的分布、生长、营养和脱胶特性进行了研究。结果表明，苎麻脱胶菌广泛分布于７省２８县（市）的１０类苗样中，从５００多株脱胶菌中筛选出一株高效脱胶菌（编号为Ｔ８５—２６０），它可在８小时内完成苎麻脱胶；Ｔ８５—２６０的生长速度快，接种后１０小时的活菌数即达顶峰；对苎麻胶质中较难被碱溶解出的甘露糖、半乳糖和葡萄糖的发酵速度快，因而在脱胶过程中定向破坏苎麻胶质主体结构，使之易于用稀碱除去，表现出生物脱胶的高效性。     

Green composites. I. physical properties of ramie fibers for environment-friendly green composites

The surface topography, tensile properties, and thermal properties of ramie fibers were investigated as reinforcement for fully biodegradable and environmental-friendly ‘green’ composites. SEM micrographs of a longitudinal and cross-sectional view of a single ramie fiber showed a fibrillar structure and rough surface with irregular cross-section, which is considered to provide good interfacial adhesion with polymer resin in composites. An average tensile strength, Young’s modulus, and fracture strain of ramie fibers were measured to be 627 MPa, 31.8 GPa, and 2.7 %, respectively. The specific tensile properties of the ramie fiber calculated per unit density were found to be comparable to those of E-glass fibers. Ramie fibers exhibited good thermal stability after aging up to 160°C with no decrease in tensile strength or Young’s modulus. However, at temperatures higher than 160°C the tensile strength decreased significantly and its fracture behavior was also affected. The moisture content of the ramie fiber was 9.9%. These properties make ramie fibers suitable as reinforcement for ‘green’ composites. Also, the green composites can be fabricated at temperatures up to 160°C without reducing the fiber properties.     

Synthesis and application of ramie fiber soft modifier comprised of carboxylate-containing polymer

In effort to improve the soft properties of ramie fiber, we synthesized a carboxylate-containing polymer for use as a modifying agent, and successfully modified the ramie fiber in a strong base with the carboxylate-containing polymer. We applied Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) to investigate the structures of the raw and modified ramie fibers, and further investigated the mechanical and dyeing properties of the raw and modified ramie fibers. The results showed that the surface of the ramie fiber underwent significant changes due to the grafting reaction of the carboxylate-containing polymer and fiber. After the chemical modification, the flexural strength and initial modulus of the modified ramie fiber decreased while tensile strength increased, indicating that the softness of the modified ramie fiber increased though its tensile resistance remained high. In addition, the fixation of reactive dyes on the modified ramie fiber was larger than that of the reactive dyes on the raw ramie fiber. Our observations of mechanical properties and dye fixation indicated that the carboxylate-containing polymer is an effective and efficient soft modifier.     

苎麻酶法脱胶的研究

用果胶酶、木聚糖酶、甘露聚糖酶进行苎麻酶法脱胶，分别进行每种酶的单一酶脱胶和3种酶联合脱胶实验，研究这3种酶对脱胶的作用。     

Modification of natural bamboo fibers for textile applications

Natural bamboo fibers have excellent properties suggesting that there is a good potential for them to be used in textiles; however, they have not received the attention that they deserve owing to their coarse and stiff quality. Therefore, a chemical method for extraction and modification of natural bamboo fibers for textile end uses were developed and optimized in this paper. The quality of natural bamboo fibers were characterized by their chemical composition, linear density, and tenacity. Experimental results show that the modified bamboo fibers are finer, with significant lower content of noncellulosic substances. The processing parameters are optimized as: 20 g/l NaOH, 3 g/l Na₅P₃O₁₀, 5 g/l Na₂SO₃, 3 g/l penetrating agent, with a fiber to liquid ratio of 1:10, at 100 °C for 2 h, and the bamboo fiber thus produced has cellulose amount of 73.25 %, fineness of 3.26 tex, average length of 44.5 mm, breaking elongation of 2.8 % and tenacity of 2.41 cN/dtex. The result of this study may offer a possibility of developing natural bamboo fibers into practical applications in textiles.     

Thermomechanical and Shape Memory Performances of Thermo-sensitive Polyurethane Fibers

This study is the first step to investigate usability of shape memory polyurethane (SMPU) fibers for smart garment applications. SMPU fibers were spun by wet spinning process and chemical/mechanical characterization was carried out. SMPU solutions were prepared with two different concentrations (20 % and 25 %) and three different coagulation bath concentrations (0 %, 1 % and 3 %) were used for determining optimum spinning parameters. For investigating influences of spinning process on crystal structure, mechanical, thermal and shape memory performances of fibers, X-ray diffraction (XRD), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), scanning electron microscopy (SEM) and mechanical tests were conducted. DSC and DMA analysis results show that shape memory polyurethane fibers have a glass transition temperature about 35-40 oC which is suitable for body temperature. Moreover, SMPU fibers showed good tensile performance with an average tenacity of 1.38 cN/dtex and elongation at break of 350 %. Thermo mechanical test results showed that, all shape memory fibers have good shape memory effect with recovery and fixity ratios up to 91 % and 71 % respectively.     

An analysis of structure and properties of a natural cellulosic fiber (Leafiran)

The ever-increasing importance of vegetable natural fibers on the global scale, the comparatively low production of this group of fibers, and the growing fiber imports by the Iranian textile industry have required numerous studies in recent years to be carried out on long natural cellulosic fibers extracted from Typha australis plant leaf. In this study, such tensile properties of the fiber under study as tenacity, modulus, elongation and work of rupture, X-ray and FTIR are investigated by alkali retting at 100 °C for 2 and 4 h. It is found that Leafiran is lignocellulosic with a tenacity approximately 25–40 cN. Tex-1, a linear density of about 4 tex, and a crystallinity of about 60 %, which are all considered to be suitable properties compared to those of other natural cellulosic fibers.