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.     

Physical Properties of Plant Fibers (Sisal,Coir) and Its Composite Material with Tamarind Seed Gum as Low-Cost Housing Material

In this study, the physical properties of sisal and coir fibers have been described. Using manual extraction procedures, the sisal fibers were extracted from the sisal plant and coir fibers from the coconut palm. Thermal analysis by differential scanning calorimetry, structural morphology by scanning electron microscopy, and the degree of sharpness of the equatorial reflections of the X-ray fiber diffraction pattern were recorded for the untreated sisal and coir fibers. Tensile strength was determined for the single fiber and the results are correlated with the tensile strength of bundle fibers. Composite material has been prepared with this plant fiber as a filler and tamarind seed gum as a matrix material. The endosperms of roasted tamarind seeds were used for the preparation of tamarind seed gum solution. The different temperature condition maintained for roasting the seeds are 130°C, 160°C, and 180°C. The tensile strength of the prepared composite material is measured and it shows dependency of the roasting temperature condition of the tamarind seed. Scanning electron microscopy and water resistivity test were conducted, and the results were reported for the prepared composite material. Low-cost housing is made using this biodegradable sisal fiber--tamarind seed gum composite material.     

Influence of microwave power on mechanical properties of microwave-cured polyethylene/coir composites

ABSTRACT

The present work deals with investigating the influence of microwave power on mechanical properties of 20 wt.% coir reinforced high-density polyethylene (HDPE) composites. Chopped coir/HDPE composites were fabricated using various microwave power levels (360 W, 540 W, 720 W and 900 W). The XRD analysis of the specimens reveals that crystallinity index in various specimens was in the range of 79.54% to 84.59%. The specimen cured at 360 W exhibited a maximum tensile strength of 29.5 ± 1.5 MPa, which is 28.26% greater than composite cured at 900 W (23 ± 1.5 MPa). Flexural strength of specimen cured at 360 W was maximum (37.74 ± 2 MPa).     

Characterization of New Natural Cellulosic Fiber from Heteropogon Contortus Plant

Natural fibers are one of effective substitute for switching artificial fiber and concentrating to reinforce polymer matrixes due to their decomposable character. This study was implied to realize physico-chemical properties of bio fiber obtained from Heteropogon contortus (HC) plant. Heteropogon contortus fibers (HCFs) had cellulose (64.87 wt. %), hemicellulose (19.34 wt. %), lignin (13.56 wt. %), and low density (602 kg/m³). The chemical functional group of HCFs was established by Fourier transform infrared spectroscopy, thermal stability of the fiber up to 220°C discovered by thermogravimetric analysis. Further the assets of HCFs proved that it can act as an excellent reinforcement material as a bio composite. Finally, the tensile properties were carried out through single fiber tensile tests, such as tensile strength, tensile modulus and microfibrillar angle.     

Effect of Green Gram Husk Nanocellulose on Banana Fiber Composite

Nanocellulose is a significant bio entity in the present-day applications of nanocomposites. In this regard, the present work focuses on fabrication of green gram husk cellulose-based hybrid nanocomposites. In the process of nanocellulose extraction, residues obtained after each stage of treatment are characterized through physical and morphological tests. Later, nanocellulose is reinforced in unsaturated polyester with 1, 3, 5, and 7 wt. % to study the tensile properties. The peak tensile strength is found to be 39 MPa at 5wt% of cellulose nanocomposites. Noting the enhancement in tensile properties of nanocomposites, nanocellulose is reinforced in banana fiber composites and its influence on mechanical properties is studied. Nanocellulose/banana fiber hybrid composites showed enhanced tensile strength, flexural strength, and impact strength.     

Natural Fibers from Plantain Pseudostem (Musa Paradisiaca) for Use in Fiber-Reinforced Composites

Agricultural crops from plantain produce a significant amount of wastes and they are currently considered worthless. Accordingly, in this study, non-wood fibers from pseudostem of plantain plants were extracted through mechanical processing to be used as reinforcing material in polyester composites. Bio-based composites were obtained using a 4% wt. of lignocellulosic reinforcement and were prepared after the fibers underwent alkaline and acetylation treatments in order to enhance the compatibility of organic loads with the polyester matrix. The higher cellulose content of plantain fibers indicates that they can be used to reinforce composites with a polymeric matrix. The plantain fibers have bast fiber bundle of around 120 µm; single fibers of around 5 µm; and mesofibers with a diameter between 0.5 and 1 µm. The results showed that plantain fibers can be used as a filler material to obtain an alternative polymer composite. The flexural strength of composites (polyester with acetylated plantain fibers) was improved 28% when the properties are compared to control composite.     

Effect of pressure on structure and properties of lyocell fabric-based all-cellulose composite laminates

In this work, all-cellulose composite (ACC) laminates were manufactured from lyocell fabric using a simple hand lay-up and compression molding-based surface-selective dissolution technique. In dissolution step, temperature and dissolution time were fixed and pressure varied. Subsequently, the dissolved cellulose was regenerated via solvent exchange and then dried by hot-pressing. The microstructures of ACC laminates were analyzed by scanning electron microscope micrographs and measuring void content. Optimum microstructure and mechanical properties were obtained with a pressure of 1 MPa, but slightly deteriorated with further increase in pressure. The highest tensile strength and modulus achieved were 44.24 ± 2.2 MPa and 1.78 ± 0.14 GPa, respectively, for ACC-3. Best flexural strength and modulus obtained were 48.95 ± 2.87 MPa and 0.96 ± 0.21 GPa, respectively, for the same sample. The T-peel strength of ACC-3 also was very high, 2.78 ± 0.34 MPa. Application of pressure during drying had a great role on controlling shrinkage and internal voids in ACC laminates.     

Exploring the potential of milkweed stalk in wood plastic manufacture

The physical and mechanical properties of milkweed composites based on different loads of milkweed flour and maleic anhydride grafted polypropylene (MAPP) using polypropylene as matrix are investigated in this study. There levels of milkweed fibers (30, 40, and 50 wt.%), one level of mixed milkweed flour (20:20 wt.% fiber:bark), and two levels of MAPP (4 and 6 wt.%) were used to prepare natural fiber-reinforced composites. Physical and mechanical properties including flexural, tension, impact, and thickness swelling were evaluated according to ASTM standards. The result demonstrated that addition of milkweed flour fluctuates mechanical properties of reinforced composite. However, the optimum load of milkweed flour was different in each test. Generally, 40 wt.% mixed flour composite in comparison with 40 wt.% milkweed composite showed lower mechanical results and higher thickness swelling. MAPP as a coupling agent improved physical and mechanical properties of milkweed-filled composites in most properties. The results of this study depicted positive effects of lignocellulose fibers and coupling gent and also negative effect of bark flour as a function of lower cellulose and higher extractive contents on physical and mechanical properties of milkweed-reinforced composites.     

Studies on Mechanical and Morphological Characterization of Developed Jute/Hemp/Flax Reinforced Hybrid Composites for Structural Applications

In the present study, an attempt has been made to develop and characterize natural fiber-based composites (jute/epoxy, hemp/epoxy, flax/epoxy) and their hybrid composites (jute/hemp/epoxy, hemp/flax/epoxy, and jute/hemp/flax/epoxy) using hand-lay-up technique. Mechanical characterization (tensile, flexural, impact, and hardness test) of the developed composites was performed. The interface between fiber and matrix was examined using scan electron microscopy (SEM). Among (jute/epoxy, hemp/epoxy, flax/epoxy), flax/epoxy composite has shown higher hardness (98 Shore-D) and tensile strength (46.2 MPa) whereas better flexural and impact strength have been shown by hemp/epoxy (85.59 MPa) and jute/epoxy (7.68 kJ/m²) composites respectively. Results showed that hybrid composites observed better mechanical properties. Jute/hemp/flax/epoxy hybrid composite showed the highest tensile strength, modulus and impact strength of 58.59 MPa, 1.88 GPa, and 10.19, kJ/m², respectively. Jute/hemp/epoxy hybrid composite achieved the maximum flexural strength of 86.6 MPa.     

麦麸纤维/小麦麸质蛋白复合膜碱性乙醇成膜体系影响因素研究

将小麦麸质蛋白(wheat gluten,WG)和麦麸纤维(wheat-bran cellulose,WC)通过溶液共混于碱性乙醇系统,采用流延成膜法制备复合膜。探讨成膜体系中料液比、麦麸纤维含量、甘油添加量、乙醇浓度、体系pH值及黄原胶添加量对复合膜物理性能抗拉强度(tensile strength,TS)、断裂伸长率(elongation at break,EAB)、水蒸气透过系数(water vapor permeability,WVP)、水溶性和透光性等的影响。结果表明:添加麦麸纤维能明显增强小麦麸质蛋白膜的抗拉强度,降低其水蒸气透过系数和水溶性,抗拉强度最高为20.44 MPa,比纯小麦麸质蛋白膜(TS=8.65 MPa)提高了140%;成膜体系各因素对复合膜各物理性能都存在不同程度的影响,其中甘油添加量影响最大,其次为麦麸纤维含量,黄原胶添加量影响最小。该研究可为进一步制备性能优异的小麦麸质蛋白复合膜提供技术参考。     

Conductive Polyaniline/Cellulose/Graphite Composite Films with High Thermal Stability and Antibacterial Activity

Functional composite films were successfully prepared from cellulose, graphite (GP), and polyaniline (PANI) using a combination of physical and chemical processes. Cellulose was dissolved in N-methylmorpholine-N-oxide monohydrate (NMMO) and regenerated in water to form the matrix. GP was dispersed in the NMMO solvent prior to the dissolution of the cellulose, and PANI was deposited on the surfaces of the cellulose/GP films by in situ chemical polymerization. The structures of the PANI/cellusose/GP composite films were investigated using X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), and SEM/energy-dispersive X-ray spectroscopy. The mechanical strengths, thermal stabilities, conductivities, and antibacterial activities of the films were studied in detail. The results showed that GP formed a multilayered structure in the cellulose matrix and that the PANI nanoparticles were tightly wrapped on the film surface. The film thickness increased from 40 m to 100 m after the addition of GP and PANI. The tensile strength of the composite films was 80~107 MPa, with the elongation at break being 3%~10%. The final residual weight of the composite films was as high as 65%, and the conductivity of the composite films reached 14.36 S/m. The cellulose matrix ensured that the films were flexible and exhibited desirable mechanical properties, while the GP filler significantly improved the thermal stability of the films. The PANI coating acted as a protective layer during burning and provided good electrical conductivity and antibacterial activity against Escherichia coli; both of these characteristics were slightly enhanced by the incorporation of GP. These PANI/cellulose/GP composite films should be suitable for use in electronics, antistatic packing, and numerous other applications.     

黄麻/豆腐渣/淀粉复合材料的制备及其性能

以黄麻纤维为增强体,经NaOH改性后的豆腐渣/淀粉混合溶液为基体,通过湿法模压制备黄麻/豆腐渣/淀粉复合材料。利用正交试验设计方案研究了豆腐渣/淀粉复配比、黄麻纤维含量、热压温度、热压强度、热压时间对复合材料板材拉伸性能和亲水性能的影响。结果表明：当豆腐渣/淀粉复配比为3、黄麻纤维含量为20%、热压强度为6Mpa、热压温度为80℃、热压时间为2min时,复合材料板材的拉伸断裂强度最优。试验所制备的复合材料片材亲水性较好,表明其具有较差的耐水性能。     

A new assessment on mechanical properties of jute fiber mat with egg shell powder/nanoclay-reinforced polyester matrix composites

ABSTRACT

Natural fiber polymer matrix composites occupy the major percentage in applications due to its ecofriendly and low-cost nature. This study investigates the mechanical properties of a polyester matrix nanocomposite reinforced by the NaOH-treated jute fabric mat (NJM) and untreated jute fabric mat (UJM). In addition, the effects of egg shell powder (ESP) and nanoclay (NC) to the above has also been studied. The matrices were prepared with different combinations of presence and absence of the ESP, NC, and both as well as different weight percentage using compression molding process. The mechanical and morphological properties of the composites were determined. The tensile strength, flexural strength, and impact strength of NJM with NC 1.5%wt and ESP 1.5%wt were found to be 29.28 MPa, 39.51 MPa and impact strength 3.03 J, respectively. This composition is superior to the other compositions. Morphological analysis of tensile fractured surface showed interfacial adhesion between UJM and NJM composites. NJM composites contained smaller amount of pullouts and the splits compared with the UJM composites, which hold up the better performance.     

Lengthwise jute fibre properties variation and its effect on jute–polyester composite

In this study, the jute reeds were equally divided lengthwise from root to tip in three portions namely root, middle and tip. The fibre diameter, fineness, tensile strength and bundle strength of the three portion jute were evaluated and compared. Unidirectional composites containing about 35(wt/wt)% jute fibre by weight were produced in unsaturated polyester resin matrix. The effect of fibre property variation in composite’s mechanical properties was studied. Tensile and flexural properties of composites made from three portions of jute reed were studied. It was observed that tensile and flexural strength of root portion based composites are 44% and 35% higher than tip portion based composites. Tensile and flexural modulus of tip portion based composites is 18% and 17% higher than root portion based composites.     

The effect of carbon fibers, glass fibers and nanoclay on wood flour-polypropylene composite properties

This study investigates the influence of different types of reinforcing fillers on the mechanical properties and wettability of wood–plastic composite material. Micro-sized glass fibers (GF) and carbon fibers (CF) and nano-sized montmorillonite (MMT) were used to reinforce a polypropylene/wood flour composite. Clear improvement of the tensile strength and modulus, up to 20 and 29 %, respectively, was observed when GF was loaded; the impact strength was reduced by 7 %; the hardness of the composite was improved by up to 7 %. No significant change in the tensile strength was observed after the CF loading; the tensile modulus was improved by 18 %; the impact strength of the composite was reduced and hardness was improved by 19 and 7 %, respectively. The MMT enhanced the tensile modulus by 34 %; the other studied mechanical properties, tensile and impact strengths, as well as the hardness of the composite decreased by 12, 32 and 15 %, respectively. The water absorption level decreased with all three filler type loadings. The morphology of the composites was examined using a scanning electron microscope (SEM).     

Influence of different wood flour fractions on the mechanical properties of injection molded WPC with cellulose propionate

This research investigated the effect of different fractions of commercial wood flour (Type c100 from JRS, Germany) on mechanical and physical properties of wood-polymer composites (WPC). The fractions were named regarding the mean lengths of their particles in µm; 80, 130, 255, 405 and 485. The composite samples were manufactured with 30 wt% of wood flour fractions of all five groups as well as the not fractionated flour, and 70 wt% of cellulose propionate (CP). The melt mass-flow rate (MFR) of the different granules, tensile strength, and modulus of elasticity, flexural strength, flexural modulus and the impact strength of the injection molded specimens as well as the water uptake were determined in this study. WPCs with the specific size range used in this investigation exhibited improved strength and modulus of elasticity in tensile and flexural tests, compared to pure CP. Using fraction 255, the mechanical properties increased the most. Tensile strength rose by 28 and 13% compared to CP and to WPC with the not fractioned wood powder, respectively. Fraction 255 increased flexural strength by 33 and 5% compared to CP and WPC with the not fractioned flour. The MFR (tested at 190 °C with 7.16 kg) of WPC_255 is the lowest with 2.3 g/10 min. Composites with the smallest particles showed the least water uptake.     

Polyvinyl Chloride Reinforced with Areca Sheath Fiber Composites—An Experimental Study

ABSTRACT

This research work deals with fibrous composites obtained by using treated and untreated areca sheath (AS) fibers reinforced in polyvinyl chloride (PVC) by injection molding process. Surface treatments of fibers have been carried out to have a better compatibility with PVC matrix. The tensile and flexural strength have been found to increase at the early stage with the increase in treated areca fiber content till optimum (18 wt% of fiber) fiber loading thereafter declines. At optimum fiber loading, the tensile strength, flexural strength and young’s modulus values are 42.38 MPa, 18.22 MPa and 2.38 GPa, respectively, which give maximum values in comparison to other fiber loadings. Thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), biodegradability tests and scanning electron microscopy (SEM) have been used for analysis. The TGA inferred that the thermal stability of the composites increased as compared to neat PVC matrix. Further, the composites exhibit excellent biodegradability property and their biodegradability increases with the increase of areca fiber content. From the properties obtained at optimum fiber loading (18 wt% of fiber), the composite can be suitable for automotive dashboard and door panel applications.     

Biocomposite Films Based on κ-Carrageenan/Locust Bean Gum Blends and Clays: Physical and Antimicrobial Properties

The aims of this work were to evaluate the physical and antimicrobial properties of biodegradable films composed of mixtures of κ-carrageenan (κ-car) and locust bean gum (LBG) when organically modified clay Cloisite 30B (C30B) was dispersed in the biopolymer matrix. Film-forming solutions were prepared by adding C30B (ranging from 0 to 16 wt.%) into the κ-car/LBG solution (40/60 wt.%) with 0.3 % (w/v) of glycerol. Barrier properties (water vapour permeability, P _vapour; CO₂ and O₂ permeabilities), mechanical properties (tensile strength, TS, and elongation-at-break, EB) and thermal stability of the resulting films were determined and related with the incorporation of C30B. Also, X-ray diffraction (XRD) was done in order to investigate the effect of C30B in film structure. Antimicrobial effects of these films against Listeria monocytogenes, Escherichia coli and Salmonella enterica were also evaluated. The increase of clay concentration causes a decrease of P _vapour (from 5.34?×?10^?11 to 3.19?×?10^?11 g (m s?Pa)^?1) and an increase of the CO₂ permeability (from 2.26?×?10^?14 to 2.91?×?10^?14 g (m s?Pa)^?1) and did not changed significantly the O₂ permeability for films with 0 and 16 wt.% C30B, respectively. Films with 16 wt.% clay exhibited the highest values of TS (33.82 MPa) and EB (29.82 %). XRD patterns of the films indicated that a degree of exfoliation is attained depending on clay concentration. κ-car/LBG–C30B films exhibited an inhibitory effect only against L. monocytogenes. κ-car/LBG–C30B composite films are a promising alternative to synthetic films in order to improve the shelf life and safety of food products.     

Biodegradable Films Based on Gelatin and Papaya Peel Microparticles with Antioxidant Properties

Biodegradable and bioactive films were prepared using gelatin from nutraceutical capsules wastes and natural antioxidants present in papaya peel. These films are intended to be an alternative to synthetic polyethylene packages in food preservation. Papaya peel was incorporated in the gelatin matrix as macroparticulate powder and in the form of microparticles, in different concentrations (2.5, 5, and 7.5%). The papaya peel powder microparticles were produced by spray drying with gelatin as wall material. The results indicated that microparticles of papaya peel powder originated a more continuous film matrix increasing the tensile strength and Young’s modulus. Films with 5 and 7.5% papaya peel macroparticulate powder showed the highest antioxidant activity with values of 0.94 and 1.44 μmol Trolox equivalents (TE)/g dried film, respectively, when compared to films with microparticles (0.63 and 0.84 μmol TE/g dried film). When applied as packaging material for lard, the films with microparticles (7.5%) were the most efficient as active barriers (higher antioxidant activity), as a lower content of peroxides (3.47 mEq/kg) quantified after 22 days. The addition of natural antioxidants through papaya peel microparticles is a promising strategy for the development of environmentally friendly packaging of food products with high-fat content and susceptible to oxidation.     

细菌纤维素-甲壳素-玉米醇溶蛋白颗粒复合膜的制备与表征

为制备功能化细菌纤维素基复合膜,本研究以细菌纤维素（Bacterial Cellulose,BC）、甲壳素纳米纤维（Chitin Nanofibrils,CH）、玉米醇溶蛋白纳米颗粒（Zein Nanoparticles,ZN）为原料,采用高效的快速抄纸技术（抽滤与热压结合）制备BC-CH-ZN复合膜。研究BC:CH质量比、ZN添加量对复合膜结构和性能的影响。进一步在ZN中加入百里香酚（Thymol,TH）,考察TH添加量对膜的热稳定性及抗菌特性的影响。结果表明,相对于纯BC膜,当BC:CH质量比从10:0减少至5:5时,复合膜的抗拉强度（从183.45 MPa到171.38 MPa）和断裂伸长率（从2.58%到2.11%）未发生明显变化。扫描电镜、厚度、红外光谱和元素分析结果共同证实ZN能有效地包覆在BC-CH复合膜内,接触角数据变化（从49.15°增加至77.28°）表明其改善了BC膜过于亲水的缺陷。TH的加入不影响BC-CH-ZN复合膜的热稳定性,且能为复合膜提供更好的抗菌效果。因此,复合CH、ZN和TH制备BC基新型功能膜材料可以改善BC过于亲水的缺陷,为开发具有更多功能特性的BC复合膜提供指导意义。