Effect of surface treatment of jute fibers on the interfacial adhesion in poly(lactic acid)/jute fiber biocomposites

Jute fibers have immense potential to be used as natural fillers in polymeric matrices to prepare biocomposites. In the present study jute fibers were surface treated using two methods: i) alkali (NaOH) and ii) alkali followed by silane (NaOH+Silane) separately. Effects of surface treatments on jute fibers surface were characterized using fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) analyses. Further, the effects of surface treatments on jute fibers properties such as crystallinity index, thermal stability, and tensile properties were analyzed by X-ray diffraction method (XRD), thermo gravimetric analysis (TGA), and single fiber tensile test respectively. The effects of surface treatment of jute fibers on interphase adhesion between of poly(lactic acid) (PLA) and jute fibers were analyzed by performing single fiber pull-out test and was examined in terms of interfacial shear strength (IFSS) and critical fiber length.     

黄麻纤维的形态结构及组分研究现状

对黄麻纤维的形态、微观结构和化学成分的研究现状进行了综述，介绍了黄麻工艺纤维中木质素和半纤维素对工艺纤维力学性质作用机理的猜测以及细胞间质成分的争论。并讨论了黄麻工艺纤维加工中的主要影响因素之一——细胞间质成分，及其他尚未解决的问题。     

Optimization of Cellulose Extraction from Jute Fiber by Box-behnken Design

Cellulose was isolated from plant material for the first time in 1839 by the French chemist Anselme Payen. In recent years, due to the need in reduce the world’s environmental problems, there has been an increase in studies related to the physical and chemical factors of cellulose. It is important to emphasize that experiments and studies with a cellulose occur individually, because of the variation in the amount of cellulose and the extraction method that differs from plant to plant. In the present study, we determined the optimal conditions for cellulose extraction of jute fiber, using the response surface method. The Box-Behnken Design (BBD) was used statistically evaluate the ratio effects of sodium hydroxide (NaOH) and sodium hypochlorite (NaClO), temperature and extraction time in the process used. The analysis of the results showed a significant variable in the linear and quadratic terms of the temperature and also a significant level of interaction in the effect between the variables of temperature and time. Besides this, the BBD used for the analysis of the extraction yield, resulted in a polynomial regression of second order, in complete agreement with experimental results, with R²=0.9627 (p<0.05). The optimal condition was obtained in a ratio of 1.3 at 45 °C for 2 h. Under the best possible conditions, the obtained experimental value is in accordance with the value predicted by the model, thus indicating a model combination and success to optimize the extraction conditions of the jute fiber pulp in the response surface methodology.     

Influence of noncellulosic contents on nano scale refinement of waste jute fibers for reinforcement in polylactic acid films

In the present study, nanofibrils of cellulose are extracted from waste jute fibers using high energy planetary ball milling process in wet condition. The rate of refinement of untreated fibers having non-cellulosic contents was found slower than treated fibers due to strong holding of fiber bundles by non-cellulosic contents. At the end of three hours of wet milling, untreated fibers were refined to the size of 850 nm and treated fibers were refined to the size of 443 nm. In the subsequent stage, composite films of poly lactic acid (PLA) were prepared by solvent casting with 3 wt% loading of untreated jute nanofibrils, treated jute nanofibrils and microcrystalline cellulose. The influence of non-cellulosic contents on mechanical properties of PLA films are investigated based on results of tensile test, dynamic mechanical analysis and differential scanning calorimetry. The maximum improvement was observed in case of treated jute nanofibril/PLA composite film where initial modulus and tensile strength increased by 207.69 % and 168.67 %, respectively as compared to neat PLA film. These improvements are attributed to the increased interaction of treated jute nanofibrils with PLA matrix due to their higher precentage of cellulosic contents and mechanically activated surface.     

黄麻与亚麻的纤维性能比较

本文对黄麻、亚麻的纤维性能进行研究比较，从纤维性能的角度探讨黄麻纤维部分替代亚麻纤维的可行性。结果表明：黄麻纤维有可能部分替代亚麻纤维。     

The novel use of sodium borohydride as a protective agent for the chemical treatment of vegetable fibers

The vegetable fibers used as reinforcement for polymer matrix composites are usually treated to improve their adhesion with the matrix. The chemical treatment with sodium hydroxide (NaOH) is widely employed, but it may damage the fiber surface structure, reducing its strength. This novel study is related to the use of hydride ions (H^?) as protective agent for vegetable fibers, under alkaline treatment, as a way to promote their use in polymeric composites. Sisal fibers were modified by immersion in a NaOH aqueous solution (2, 5, and 10 % wt/vol) with or without the addition of sodium borohydride (NaBH₄) (1 % wt/vol) under different treatment conditions. The treated fibers were characterized via density and moisture content analyses and also using scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The effectiveness of NaBH₄ to protect the sisal fiber was more pronounced in moderate NaOH concentrations (5 %) at room temperature or higher for shorter alkaline treatment times.     

Effect of the low and radio frequency oxygen plasma treatment of jute fiber on mechanical properties of jute fiber/polyester composite

We investigated the surface modification of jute fiber by oxygen plasma treatments. Jute fibers were treated in different plasma reactors (radio frequency “RF” and low frequency “LF” plasma reactors) using O₂ for different plasma powers to increase the interface adhesion between jute fiber and polyester matrix. The influence of various plasma reactors on mechanical properties of jute fiber-reinforced polyester composites was reported. Tensile, flexure, short beam shear tests were used to determine the mechanical properties of the composites. The interlaminar shear strength increased from 11.5 MPa for the untreated jute fiber/polyester composite to 19.8 and 26.3 MPa for LF and RF oxygen plasma treated jute fiber/polyester composites, respectively. O₂ plasma treatment also improved the tensile and flexural strengths of jute fiber/ polyester composites for both plasma systems. It is clear that O₂ plasma treatment of jute fibers by using RF plasma system instead of using LF plasma system brings about greater improvement on the mechanical properties of jute/polyester composites.     

黄麻和红麻纤维磨木木质素的红外光谱特征

从黄麻和红麻纤维中分离出磨木木质素,利用红外光谱分析了两种麻纤维磨木木质素的特征峰及归属,得知磨木木质素中有复杂的官能团,含有羟基、羰基、甲基等基团,木质素结构中含有相当数量的紫丁香基单元。根据黄麻和红麻纤维磨木木质素的红外光谱吸收峰强度,推断其结构属于阔叶木类木质素化学结构GS型木质素。     

恢复黄麻生产 开发黄麻新产品

黄麻在我国具有近千年种植历史，尽管作为传统包装材料使用正居于次要地位，但由于黄麻纤维具有优质、可降解特性，我国麻纺科技人员及企业正在开发新产品，如高支黄麻纱、布；黄麻／棉、黄麻／化纤、黄麻／羊毛、黄麻／丝等混纺高档产品，以及汽车、装饰等产业用品。许多企业正呼吁恢复我国黄麻种植，以减少对孟加拉进口黄麻的依赖。     

Easy Preparation of Dietary Fiber with the High Water-Holding Capacity from Food Sources

Dietary fibers were prepared as alkali- and acid-insoluble fractions with chemical phosphorylation from Tossa jute (Corchorus olitorius), defatted soybean (Glycine max), and Shiitake (Lentinula edodes). The dietary fiber fractions treated with alkaline solution containing sodium metaphosphate had the lower protein content and higher total dietary fiber content than those of the preparations without phosphorylation. Alkaline extraction followed by phosphorylation led to a 1.5-fold increase in the water holding capacity of dietary fiber compared with no phosphorylation, whereas the binding capacity to bile acids of dietary fiber was almost the same. The alkali- and acid-insoluble extraction with phosphorylation provided an efficient preparation of water-insoluble dietary fiber with high-water holding capacity from various food sources.     

Impact of succinic anhydride on the properties of jute fiber/polypropylene biocomposites

Chemical treatment is an often-followed route to improve the physical and mechanical properties of natural fiber reinforced polymer matrix composites. In this study, the effect of chemical treatment on physical and mechanical properties of jute fiber reinforced polypropylene (PP) biocomposites with different fiber loading (5, 10, 15, and 20 wt%) were investigated. Before being manufactured jute fiber/PP composite, raw jute fiber was chemically treated with succinic anhydride for the chemical reaction with cellulose hydroxyl group of fiber and to increase adhesion and compatibility to the polymer matrix. Jute fiber/PP composites were fabricated using high voltage hot compression technique. Fourier Transform Infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) tests were employed to evaluate the morphological properties of composite. Succinic anhydride underwent a chemical reaction with raw jute fiber which was confirmed through FTIR results. SEM micrographs of the fractured surface area were taken to study the fiber/matrix interface adhesion and compatibility. Reduced fiber agglomeration and improved interfacial bonding was observed under SEM in the case of treated jute fiber/PP composites. The mechanical properties of jute/PP composite in terms of Tensile strength and Young’s modulus was found to be increased with fiber loading up to 15 wt% and decreased at 20 wt%. Conversely, flexural strength and flexural modulus increased with fiber loading up to 10 wt% and start decreasing at 15 wt%. The treated jute/PP composite samples had higher hardness (Rockwell) and lower water absorption value compared to that of the untreated ones.     

不同处理对黄麻纤维木质素去除及织物性能的影响

本文研究了草酸铵、漆酶以及木聚糖酶单独或联合处理对黄麻机织布中木质素的去除作用及对织物褶皱、力学性能的影响。结果表明,漆酶单一处理仅能去除少量的木质素,联合处理可提高木质素的去除效率,以草酸铵、木聚糖酶、漆酶联合处理效果最好。在ATR红外谱图中,草酸铵、木聚糖酶、漆酶联合处理后的黄麻机织布较未处理织物在1594 cm-1、1506cm-1和1424 cm-1处的木质素芳香族特征吸收峰,1731 cm-1和1646 cm-1处的木质素羰基特征吸收峰及1242 cm-1-1031 cm-1处的半纤维素醚键特征吸收峰均有减弱,说明经草酸铵、木聚糖酶、漆酶联合处理后黄麻纤维表面木质素和半纤维素含量降低。经处理后黄麻机织布褶皱回复角提高,其中草酸铵、木聚糖酶、漆酶联合处理褶皱回复性最佳。漆酶单独处理后黄麻机织布断裂强力和断裂延伸率均提高,联合处理后断裂强力降低,断裂延伸率提高。     

Effect of reinforcement and chemical treatment of fiber on The Properties of jute-coir fiber reinforced hybrid polypropylene composites

Present research investigates the mechanical properties of jute-coir fiber reinforced hybrid polypropylene (PP) composite with fiber loading variation and observes the effect of chemical treatment of fiber on property enhancement of the composites. Composites were manufactured using hot press machine at four levels of fiber loading (5, 10, 15 and 20 wt%). Fiber ratio’s were varied (jute:coir=1:1, 3:1 and 1:3) for 20 % fiber loaded composites. Both jute and coir fiber was treated using 5 % and 10 % NaOH solutions. Composites were also prepared using treated fiber with jute-coir fiber ratio of 3:1. Tensile, flexural, impact and hardness tests and Fourier transform infrared spectroscopic analysis were conducted for characterization of the composites. Tensile test of composite showed a decreasing trend of tensile strength and increasing trend of the Young’s modulus with increase in fiber loading. During flexural, impact and hardness tests, the flexural strength, flexural modulus, impact strength and hardness values were found to be increased with increase in fiber loading. All these properties enhanced with the enhancement of jute content except impact strength. 5 % NaOH treatment provided an improving trend of properties whereas, 10 % NaOH treatment showed the reverse one. The FTIR analysis of the composites indicated decrease of hemicelluloses and lignin content with alkali treatment.     

Morphological and crystalline characterization of NaOH and NaOCl treated Agave americana L. fiber

This study investigates the effect of NaOH and NaOCl treatments on chemical composition, morphology and crystalline structure of Agave americana L. fibers. These fibers have been subjected to NaOCl and NaOH alkali treatments at different concentrations.The percentages of lignin and hemicellulose show a decrease with alkaline treatments which, in turn, induces a modification of both morphological and crystalline structures.Unit cell dimensions and crystallite size were more affected with NaOH treatment than NaOCl one. This may result from the mercerisation process which occurs with caustic soda treatment.The observed defibrillization on the treated fiber surface proves the dissolution of the non-cellulosic components present in the fiber cell wall by NaOH and NaOCl treatments. These morphological changes may improve the interaction between matrix and fiber in composites.     

Acetylation of Jute fiber to improve oil absorbency

Raw Jute was modified by acetylation process with acetic anhydride using N-bromosuccinimide (NBS) as a catalyst in a solvent free system which was found to be effective catalyst. The reaction parameters were optimized which were found to be time 1 h, temperature 120 °C, catalyst concentration 2 %, and solid to liquid ratio 1:20. The product so formed was characterized by FT-IR and TG and its degree of acetylation was also evaluated. The extent of acetylation was measured by weight percent gain (WPG). Acetylation resulted in significant increase in hydrophobic properties of the jute fiber. The oil sorption capacity of the acetylated jute was higher than that of the commercial synthetic oil sorbents such as polypropylene fibers as well as raw jute. Therefore, these oil sorption-active materials which are also biodegradable can be used to substitute non-biodegradable synthetic materials in oil spill cleanup.     

Effects of lipase on poly(lactic acid) fibers

Two types of lipases, L3126 and Lipex 100L, were used to modify the surface of poly(lactic acid) (PLA) fiber by measuring weight loss percentage and wettability of the fiber in this work. The influence factors were discussed and optimized based on single-factor experiments. The optimal conditions for the modification of poly(lactic acid) fiber with lipases were determined as follows: incubation with lipase L3126 of 0.5 g/l at 45 °C and pH 8.5 for 8 hours and incubation with lipase of 10 ml/l at 40 °C and pH 7.5 for 10 hours. Lipase L3126 showed higher biodegradation ability to poly(lactic acid) fiber than lipase Lipex 100L. The scanning electron microscopy confirmed that both of the two lipases could lead to the formation of etching characters on treated poly(lactic acid) fibers in comparison with the blank samples. Furthermore, the wettability of the fibers treated with the lipases was evidently improved, especially Lipase L3126.     

An Investigation on Wear and Dynamic Mechanical behavior of Jute/Hemp/Flax Reinforced Composites and Its Hybrids for Tribological Applications

Bio-materials have ignited a quest among research fraternity to be used in every possible field of applications like automobile, sports, medical, civil and textile industry. Application spectrum of natural fiber reinforced polymer composites is spreading globally in every field of engineering having structural and tribological applications. The present work investigates the tribological performance of regionally available inexpensive plant based natural fiber reinforced polymer composites. In this work, three different types of natural fibers (jute, hemp, and flax) were reinforced with epoxy matrix to fabricate natural fiber reinforced polymer composites (NFRP) and their hybrid composites (jute/hemp/Epoxy, hemp/flax/epoxy and jute/ hemp/flax/epoxy) using hand-layup technique. Tribological performance of the developed bio-composites were evaluated in terms of frictional characteristics and sliding wear under dry contact condition at different process parameters, such as applied load (10-50 N), sliding speed (1-5 m/s) and sliding distance (1000-2000 m). Experimental results of wear analysis confirmed that incorporation of natural fibers into epoxy polymer matrix significantly improved the wear behavior of the developed NFRP composites in comparison to neat epoxy polymer. Among all the developed composites, jute/epoxy composite achieved the highest coefficient of friction, frictional force and specific wear rate. Dynamic mechanical analysis (DMA) was also analyzed to evaluate the viscoelastic behavior of the developed composites. The surface morphology of samples after wear test was examined by scanning electron microscopy to investigate and propose the possible wear mechanism of the developed composites.     

Surface treatments of jute fabric: The influence of surface characteristics on jute fabrics and mechanical properties of jute/polyester composites

In this study, jute fabrics were modified by alkali, micro-emulsion silicon (MS) and fluorocarbon based agents (FA) in order to enhance the interfacial adhesion between the polyester matrix and the jute fiber. X-ray photoelectron spectroscopy (XPS) and contact angle measurements were used to characterize fiber surfaces. The effects of various surface treatments on the mechanical and morphological of jute/polyester composites were also studied. All surface treatments were shown to improve the tensile, flexural strengths and interlaminar shear strengths of the composites. Moreover, the maximum improvement in the mechanical properties was obtained for the FA treated jute/polyester composites. SEM micrographs of the tensile fracture surface of jute/unsaturated polyester composites also exhibited improvement of interfacial and interlaminar shear strengths by the alkali, MS and FA treatments of jute fibers.     

Effect of kenaf and EFB fiber hybridization on physical and thermo-mechanical properties of PLA biocomposites

Kenaf/empty fruit bunch/polylactic acid (kenaf/EFB/PLA) hybrid biocomposites were prepared using hot press technique. The ratio of fiber to polylactic acid was set at 60:40 with 1:1 ratio between kenaf and empty fruit bunch fibers. Physical, mechanical and thermal properties of hybrid biocomposites were subsequently characterized using Fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, tensile and water absorption tests. Test results indicated that mechanically stronger fiber was able to support the weaker fiber. Hybrid fiber biocomposite had higher crystallinity as compared to single fiber biocomposite. Water absorption of hybrid composite was higher as compared to single fiber composite. Thermal result revealed that hybridization of fiber was not significantly influence the thermal properties of composites. However, the presence of two different fibers proposed good wettability properties, which could reduce the formation of voids at the fibers-polymer interface and produce composites with high stiffness and strength.     

黄、红麻资源的优化与开发利用

本文针对目前我国黄麻纺织业存在的原料过剩，产品结构单一，质量档次不高，加工技术和设备落后，工业体系萎缩，从而直接影响到黄、红麻种植业发展的现状，提出了应用现代纺织技术改造黄麻纺织技术与设备，提高黄、红麻产品本身的档次，发挥黄、红麻原料在亚麻、苎麻等加工业中的替代利用，以黄、红麻原料与其它纤维的混合加工来开发新型产品，丰富和扩大其产品应用领域等几个方面，探讨如何促进我国黄麻纺织业的发展。