红麻粗纱酶解效果测定及其分析

对红麻韧皮纤维经生物酶一浴法脱胶改性处理后,运用咔唑比色法测定红麻粗纱果胶和木质素的残留量,定量测定果胶的去除率。分析了酶浓度、温度、pH值和作用时间对酶解后果胶及木质素去除率的影响。实验表明,复合酶对红麻粗纱中果胶和木质素去除效果较好,所得纤维质量明显改善。     

脱胶方法对棉秆皮纤维成分及结构的影响

对原棉秆皮不同部位进行化学成分分析,利用常温水沤、常压脱胶及高压脱胶对棉秆皮进行处理,对脱胶后棉秆皮进行化学成分分析.实验结果表明:高压脱胶后棉秆皮纤维中的半纤维素和木质素含量下降最为明显,纤维素含量提高.对不同方法处理后的棉秆皮纤维的长度、线密度进行测量,用SEM、FT-IR、XRD对处理后的棉秆皮纤维表面形态结构、聚集态结构进行了表征,同时对脱胶后的棉秆皮纤维进行强伸性能等测试并得出断裂曲线.     

脱胶方法对棉秆皮纤维成分及结构的影响

对原棉秆皮不同部位进行化学成分分析,利用常温水沤、常压脱胶及高压脱胶对棉秆皮进行处理,对脱胶后棉秆皮进行化学成分分析．实验结果表明：高压脱胶后棉秆皮纤维中的半纤维素和木质素含量下降最为明显,纤维素含量提高．对不同方法处理后的棉秆皮纤维的长度、线密度进行测量,用SEM、FT-IR、XRD对处理后的棉秆皮纤维表面形态结构、聚集态结构进行了表征,同时对脱胶后的棉秆皮纤维进行强伸性能等测试并得出断裂曲线．     

Influence of various retting methods on properties of kenaf fiber

Gum, as the important noncellulosic tissue present in kenaf fiber, has a close relation with downstream processing and product properties, so the predominant task in pretreatment of kenaf fiber for textile application, retting, is to remove gum including pectin, hemicellulose, lignin, and other impurities without damage to cellulose fiber. The traditional retting method is water retting; that is, the harvested kenaf bast is soaked in natural water (rivers or tanks) in which indigenous bacteria attack the gum in an anaerobic process, yielding much water pollution. Currently, much interest has been focused on various retting methods in order to seek one environmentally-friendly method. Therefore, microbe, chemical, water, and microbe–chemical rettings are performed in this experiment. Retted kenaf fibers at optimal conditions of various retting methods are then characterized and compared by light microscopy and indices consisting of residual gum content, fineness, tenacity, elongation, and softness. In addition, chemical oxygen demand (COD) is also tested. The results indicate that microbe retting induces higher residual gum content and lower elongation but better tenacity and softness and finer fiber; chemical retting gives lower tenacity and thicker fiber; water retting produces weak, poor quality fiber; and microbe–chemical retting produces moderate indices.     

The Dimensional Distribution of Kenaf and Apocynum Fibers

ABSTRACT

In this research, single fiber cell separation method was studied and optimized. More than 200 fiber cell dimensional sizes of kenaf and apocynum were analyzed. Furthermore, the diameter changes of kenaf fiber cell before and after different degumming treatments were also explored. Results showed that the average length and diameter of kenaf fiber are 2.16 mm and 10.56 μm, while the average length and diameter of apocynum fiber are 9.04 mm and 7.41 μm. It was also found that the average diameter of kenaf and apocynum fibers decreased with the degumming process, and the diameter distribution became more even.     

不同醇及助剂对大麻有机溶剂脱胶效果的影响

为解决传统化学脱胶污染大、损伤纤维等弊端以及生物脱胶成本高、耗时长等问题,使用高沸点醇类有机溶剂对大麻麻皮进行脱胶处理,提高脱胶选择性,确保反应安全环保;同时针对脱胶后大麻纤维残胶率及物理力学性能不足的问题,引入碱性钠盐助剂辅助脱胶。研究了4种不同醇类(乙二醇、1,2-丙二醇、丙三醇和1,4-丁二醇)和3种不同碱性钠盐助剂(碳酸钠、碳酸氢钠及硅酸钠)对大麻麻皮脱胶效果的影响,对脱胶后纤维的各项性能进行了对比。结果表明:经乙二醇脱胶的大麻纤维性能在4种醇类中最好,木质素去除效果最佳,纤维残胶率为8.67%,断裂强度偏低,为3.92 cN/dtex;3种碱性钠盐助剂中,碳酸钠辅助乙二醇脱胶的大麻纤维残胶率为7.71%,断裂强度为4.84 cN/dtex,符合大麻精麻的国家标准。     

Flax retting by degumming composite enzyme produced by Bacillus licheniformis HDYM-04 and effect on fiber properties

Flax enzymatic retting with composite enzyme produced by microbes with inexpensive substrates is widely researched due to less contamination and lower cost. Bacillus licheniformis HDYM-04, isolated from a liquid sample of flax retting pool, efficiently produced degumming enzymes after 48 h of fermentation with inexpensive konjaku flour, consisted of 587.5 U/mL pectinase, 365.2 U/mL mannanase, and 140.1 U/mL xylanase. Almost half the maximum activity of three above-mentioned degumming enzymes was maintained at pH 4.0–6.0 which demonstrated its stability in pH condition of flax retting. After 120 h of retting with this composite enzyme, scanning electronic microscopy showed more significant reduction in gummy components on the fiber surface than those of water retting. The fiber strength was 182.4 ± 9.3 N, 14.3% higher than water-retted samples. The long fiber rate and fiber yield also verified higher fiber productivity. The results permitted this degumming composite enzyme an applicable potential in flax retting.     

韧皮纤维生物脱胶制浆的研究及发展

简单介绍了果胶的结构、化学组成及生物脱胶机理,详细总结了韧皮纤维酶法和发酵浸渍法脱胶制浆的研究、应用和发展情况,并对影响发酵浸渍法制浆原料和脱胶菌株的特性,特别是脱胶过程中主要外界因子进行了综述.     

Removal of Heavy Metal Ions from Aqueous Solutions Using Lignocellulosic Fibers

Abstract

Spruce, coconut coir, sugarcane bagasse, kenaf bast, kenaf core, and cotton were tested for their ability to remove copper, nickel and zinc ions from aqueous solutions as a function of their lignin content. The fibers were analyzed for sugar and lignin content and extracted with di-ethyl ether, ethyl alcohol, hot water, or 1% sodium hydroxide.

The order of lignin content in un-extracted fibers is coconut coir > spruce > kenaf core > bagasse > kenaf bast > cotton. The fiber with the highest level of heavy metal removal was kenaf bast that had a very low level of lignin, showing that removal of heavy metals does not correlate with lignin content. Cotton, with about 1% lignin, was very low in metal ion sorption while all of the fibers containing lignin did remove heavy metal ions showing that lignin does play a role in metal ion sorption. Extraction with the various solvents removed different cell wall components and did change heavy metal sorption that indicates that cell wall chemistry and architecture may also be important factors in the sorption of heavy metals from aqueous solutions using lignocellulosic fibers.     

棉秆皮机械-生物酶联合脱胶工艺

 本文利用机械-生物酶联合脱胶工艺对棉秆皮进行脱胶。应用模糊数学方法处理机械-生物酶联合脱胶的正交实验评价指标值,解决了两个评价指标优化条件不一致的问题,得出机械-生物酶联合脱胶优化工艺参数为酶浓度6%,pH值4.4,温度60℃,时间8h,棉秆皮纤维的残胶率为8.09%,木质素残余率为9.64%。采用FTIR、SEM和XRD进行测试,讨论了棉秆皮纤维的化学结构、微观表面形态及纤维素结构的变化,为棉秆皮纤维的染色与产品开发提供理论指导。     

Study on the Application of Kenaf Core as a Composite Reinforcement: Injection Molding of Kenaf Core/Poly(l-lactide) Compounds

Injection molding was performed using poly(l-lactide) (PLLA) as a matrix and by varying the reinforcements, i.e., dry-distilled kenaf core (D-core) or untreated kenaf bast fibers, and the physical properties for these composites were subsequently compared. The dry-distillation was able to reduce the moisture content of D-core by a maximum of 4.2% as compared with untreated control core. As a result, the hydrophobicity was increased, which contributed to favorable Charpy impact strength and tensile properties of the D-core/PLLA composite relative to the kenaf bast fiber/PLLA composite. Moreover, the puffing phenomenon, which arises when heating with a microwave oven due to the vaporization of water dispersed within the interfacial regions and associated softening of the PLLA matrix by the heated vapor, was completely suppressed for the D-core/PLLA composite, whereas a large puffing ratio was observed for the kenaf bast fiber/PLLA composite. Reducing the moisture content also effectively suppressed the occurrence of transesterification reactions, leading to a decrease in the molecular weight of PLLA. However, the apparent nucleation effect of the D-core remains slightly inferior to that for the hydrophilic bast fibers due to its stronger affinity for PLLA molecules.     

罗布麻中黄酮的超临界CO2萃取及其抗菌性

为解决传统脱胶工艺罗布麻韧皮纤维中黄酮化合物的浪费问题,对罗布麻韧皮纤维采取超临界脱胶预处理的同时,利用超临界CO2 提取其黄酮有效成分,研究分析影响罗布麻中黄酮萃取的4个主要因素,然后对萃取液进行了高效液相色谱分析和抗菌实验。结果表明：助溶剂主要影响超临界流体的极性,随着助溶剂含量的增加,超临界流体极性的增加提高了黄酮萃取率,但助溶剂含量过高时,过多水分易造成萃取管路堵塞,使黄酮的萃取效率降低;在45 ℃、20 MPa时黄酮萃取率较高,升高或降低压力与温度均会影响黄酮萃取效果;随着超临界CO2流量的增加,黄酮萃取率逐渐增加,但对萃取设备要求更高;罗布麻中黄酮化合物具有良好的抗菌效果,是罗布麻纤维具有抗菌性能的原因之一。     

罗布麻微生物脱胶工艺优化

 为了提高枯草芽胞杆菌对罗布麻的脱胶效率,根据菌种生长与酶催化反应所需温度的差异,将罗布麻生物脱胶过程分为2个阶段,并对脱胶工艺进行优化。试验结果表明：在磷酸氢二钾添加量为0.8%、浴比为1:25、枯草芽胞杆菌接种量为0.5%的条件下,在37℃脱胶18h,再升温至45℃脱胶0.5h,取得了良好的脱胶效果,罗布麻脱胶后的残胶率为10.84%,与未进行后阶段升温脱胶所得的残胶率相比降低了4.95%。     

The Influences of Fibre Parameters on the Tensile and Flexural Response of Lightweight Thermoplastic Kenaf Fibre Reinforced Metal Composites

ABSTRACT

The increasing demand for high performance and lightweight materials has stimulated the development of alternative materials, namely fiber metal laminates (FMLs). FML is a sandwich structure which is formed by bonding the metallic layers with composite as core constituent using an adhesive agent. In this study, the mechanical behavior of FMLs with the core constituents of environmental friendly kenaf bast fiber reinforced polypropylene composites bonded with aluminum skin layers was investigated. The effects of fiber compositions (50, 60, and 70 wt.%), fiber lengths (30, 60, 90 mm), and alkali treatment on the mechanical responses of FML were investigated. The overall results revealed that the increase of fiber composition and fiber length reduces the mechanical strength of FML owing to the agglomeration of natural fibers when the fiber length exceeds the critical limit. However, the chemical treated kenaf bast fiber reinforced FML showed a significant enhancement of the mechanical properties in comparison to the non-treated fiber reinforced FML owing to the improved fiber-matrix adhesion level.     

Degumming of ramie bast fibers by Ca2+-activated composite enzyme

In recent years, special attention has been paid to the application of biotechnology in the textile industry. In this study, composite enzyme (contained pectatelyase/hemicellulase/laccase) was employed to degum the ramie bast successfully. Interestingly, the activities of enzymes were enhanced by promotion of Ca²⁺ activated remarkably. The test of degummed ramie fiber performance demonstrated that fiber fineness, breaking strength, whiteness, and residual gum of fibers have greatly improved. Further, the structure and morphous of the fibers before and after degumming was examined and analyzed. The results showed that the gum, hemicellulose, and lignin were removed effectively and treated fibers had the typical cellulose I structure suitable for direct textile and other applications. These outcomes suggested that Ca²⁺-activated composite enzyme could degum the gum of ramie bast effectively, which provided a method to improve the quality of ramie fibers and a theoretical basis for flax degumming technique on an environmentally-friendly basis.     

棉杆皮纤维生物化学联合脱胶工艺研究

将生物酶处理技术应用于棉杆皮纤维制取工艺,采用生物化学联合脱胶方法,研究了棉杆皮纤维的脱胶工艺。通过正交试验及模糊综合评价法,确定生物酶脱胶的最佳工艺为果胶酶质量分数12%(按织物质量计算),温度40℃,pH值4.4,时间30h,浴比1:30,化学脱胶处理的最佳工艺为NaOH质量浓度8g/L,H2O2质量浓度7g/L,温度90℃,时间45min,浴比1:50。     

Survey and Recent Report on Enzymatic Processing of Bast Fibers

SUMMARY

In reference to previous presentations during meetings of Working Group 2 (WG2): “Bioprocessing of Bast Fibres,” acting within the COST Action 847 Project “Textile Quality and Biotechnology,” a further update of current world knowledge on biological processing of fiber plants and textiles was prepared. This survey covers the research on utilization of particular groups of enzymes in these processes. Main areas of enzyme application in bast fiber textile industry, according to literature from 2001-2004 are: degumming of bast fibers and scouring in textile industry (before and after bleaching).

The report also covers the results of studies on enzymatic processing of fiber plants carried out at the INF, in which the work is continued on application of enzymes in: degumming of flax straw, modifying of the short technical flax fibers, linen and hemp fabrics modification, and bonding of lignocellulosic composites.     

Comparison of the performance of kenaf fiber using different reagents presoak combined with steam explosion treatment

To enhance the degumming effect of steam explosion on kenaf fiber, different chemical reagents including hydrogen peroxide (H₂O₂), sulfuric acid (H₂SO₄), and sodium hydroxide (NaOH) presoak combined with steam explosion were used and compared in this article. Distilled water coupled with steam explosion treatment and kenaf raw samples were used as control. The fiber morphology, chemical composition, crystalline structure, degree of fineness, and breaking tenacity of kenaf fibers after treatment were studied. The results showed that hydrogen peroxide (H₂O₂) performs better on removing lignin. It not only splits fibers, but also keeps the fiber’s tenacity during steam explosion treatment. Dilute sulfuric acid (H₂SO₄) performs better on hemicellulose removal, but it damages the fiber cellulose during steam explosion treatment and cause the fiber strength decrease a lot. Sodium hydroxide (NaOH) performs the best on removing hemicellulose and lignin, and splits fiber well. However, the breaking tenacity of the fiber is lower than the fiber pretreated by H₂O₂. Besides, NaOH is a pollutant to the environment. In conclusion, H₂O₂ could be considered as the most promising reagent to be used in combined presoak-steam explosion system.     

Effect of Inoculation of Pectinolytic Mixed Bacterial Culture on Improvement of Ribbon Retting of Jute and Kenaf

Abstract

Jute and kenaf are among the annually renewable fibre crops mainly grown over tropical and subtropical Asian countries. They are possibly the world's largest source of lignocellulosic bast fibre which is extracted from plants by a natural microbial process known as retting. But acute shortage of water for retting and the environmental pollution created from conventional system of retting has demanded for new method of retting.

The new method of retting launched has been recognized as ribbon retting. In ribbon retting barks are removed from jute and kenaf plants mechanically or manually in the form of ribbon. The ribbons are coiled and then allowed for retting in water with or without using a microbial inoculum. Ribbon retting has the following advantages over conventional retting: (1) It requires lesser volume of water, (2) it is faster, (3) it produces lesser environmental pollution, and (4) it produces improved quality fibre. Addition of efficient pectinolytic microbial inoculum may further boost up or improve the ribbon retting process.

From the present study it is understood that inoculation of a specific mixed bacterial culture in combination with 0.5% urea as N-supplement caused faster ribbon retting of jute and kenaf. Ribbon retting conducted in cement retting tank was faster than that in polythene tank. The mixed bacterial culture in combination with urea produced stronger, finer and brighter coloured jute and kenaf fibre in comparison to uninoculated control. One hundred twenty-day-old plant was found most suitable for ribbon retting. Ribbon retted fibre with pectinolytic mixed bacterial culture in combination with urea obtained higher grade in comparison to uninoculated control. Such ribbon retted fibres produced standard and regular quality yarn.