Luffa Cylindrica Fibers Research Articles

Mechanical Properties of Injection Molded Poly(lactic) Acid—<i>Luffa</i> Fiber Composites

The influence of cellulose nano fibers extracted from the fruit of luffa cylindrica (LC) on the tensile, flexural and impact properties of composite materials using poly lactic acid (PLA) processed by micro compounding and injection molding was studied. Preliminary results suggested promising mechanical properties. The impact strength, tensile strength and flexural strength of the composites increased with incorporation of very low content of LC fiber up to 2 wt%. But when the wt of LC fiber in the composite increased (5 wt% and 10 wt%), mechanical strength of the composites reduced probably due to agglomeration of cellulose fibers. However, modulus of composites was enhanced with increase in wt of fiber content in the composites. Before reinforcement, the LC fibers were modified with calcium phosphate in order to explore the possibilities of using these composites in biomedical industries. The novelty of this work is that there is no use of compatiblizer and coupling agent during the processing so that the cost of processing is reduced.

The Effect of Ultrasonic Treatment on Dyeing of Luffa cylindrica Fibers

In this research work, conventional and ultrasonic treatments on exhaust dyeing of natural Luffa cylindrical (LC) fibers with reactive dyes were studied. Accordingly, the samples were alkali scoured, bleached with H 2 O 2 and dyed with C.I. Reactive Red 241 and C.I. Reactive Blue 19 at 60 °C, 60 min with or without ultrasonic energy. The colouristic properties, penetration behavior and colour fastnesses were investigated and compared with each other. Using ultrasonic energy for dyeing LC fibers enhances the exhaustion of dye, good colouristic properties and colour fastnesses in dyeings are achieved. The ultrasonic power seems promising since it enhances colour yields and reduces process time.

Dynamic Mechanical Behavior of <i>Luffa cylindrica</i> Fiber-Resorcinol Composites

Dynamic mechanical behaviour of resorcinol-formaldehyde matrix and its composites reinforced with natural fibers of Luffa cylindrica (LC) has been studied. The effects of fiber loading, alkali treatment on fiber, temperature and frequency on storage modulus and mechanical-loss factor of the composites were studied. The dynamic mechanical behaviour of the composites and pure matrix has been investigated in the frequency range from 0.1 Hz to 10 Hz and temperature range from 26℃ to 100℃. The experimental results show that the values of storage modulus of the composites increase with increase in fiber loading. The storage modulus of treated LC fiber composites were found to be enhanced when compared with the untreated fiber composites. It was also found that mechanical-loss factor was more when untreated LC fibers were incorporated in the composites and decreased with the incorporation of treated LC fiber. The storage modulus of all the composites increased with frequency but decreased with rise of temperature. The glass transition temperature of the composites was evaluated from the peaks of tan delta variations.

FTIR and Raman Studies of Cellulose Fibers of <i>Luffa cylindrica</i>

In view of biomedical applications of cellulose fibers in orthopedics, dentistry and reconstructive surgery, Luffa cylindrica (LC), a local forest product of Orissa, India, has been used for preparation of alkali treated LC fiber modified with calcium carbonate and calcium phosphate separately by following standard procedures. FTIR and Raman spectra were obtained for these samples at wavelength range 500 - 4000 cm–1 and 300 - 3000 cm–1 respectively. Lattice structures of cellulose i.e., crystalline cellulose and amorphous cellulose were detected using Raman spectroscopy and discussed. The property of cellulose such as its degree of crystallinity was determined from intensity of FT IR peaks and was found to be 74.12%. The presence of calcite and hydroxy apatite, polymorphs of calcium carbonate and calcium phosphate respectively were confirmed in the treated modified LC fibers which can be used as bioactive materials.

Evaluation and modeling of methyl green adsorption from aqueous solutions using loofah fibers

Loofah fiber, an economical adsorbent material, was first developed for the methyl green (MG) removal from aqueous solutions. The loofah fibers were characterized by SEM, FTIR, N2-BET and the potentiometric titration. The pH, contact time and temperature were examined extensively. The adsorption of MG on loofah fiber increased very quickly in the pH range 3.0 to 7.0, remaining a high level at pH>7.0. The kinetics of adsorption of MG on the loofah fiber was proved to coincide with pseudo-second-order kinetic models (r2>0.99) very well. Langmuir isotherm was demonstrated to fit the experimental data better than Freundlich isotherm model. Monolayer adsorption capacity increased with the increase of temperature. Thermodynamic constants were evaluated, and the results indicated that MG adsorption onto loofah fiber was feasible, spontaneous and endothermic. The high removal efficiency of MG on loofah fiber suggested that the loofah fiber was suitable material in MG pollution cleanup.

Removal of Cu(II) by loofah fibers as a natural and low-cost adsorbent from aqueous solutions

As a natural and low-cost material, loofah fibers were applied as an adsorbent to remove Cu(II) from aqueous solutions. The effect of adsorption conditions, such as pH, foreign ions, humic substances (HS), contact time and temperature on the Cu(II) removal, was investigated intensively. The adsorption of Cu(II) on loofah fibers was strongly dependent on pH and foreign ions, and the adsorption of Cu(II) was increased in the presence of humic acid (HA) at pH<8.0 but decreased at pH>8.0. The Langmuir and Freundlich isotherm models were used to simulate the adsorption isotherms. The simulated adsorption isotherms, which were obtained from Langmuir and Freundlich isotherm models, showed that both of the two models were applicable to this system. On the basis of the experimental data, the Langmuir isotherm model could fit it better according to linear correlation coefficient (R2). The optimum kinetics of adsorption was found to fit the pseudo-second-order kinetic model. The values of ΔΗ° and ΔG° indicated that the adsorption process was exothermic and spontaneous.

Amputation of congo red dye from waste water using microwave induced grafted Luffa cylindrica cellulosic fiber

The present study deals with the surface modification of Luffa cylindrica fiber through graft copolymerization of methyl acrylate/acrylamide (MA/AAm) via microwave radiation without the use of initiator. Various reaction parameters effecting grafting yield were optimized and physico-chemical properties were evaluated. The grafted Luffa cylindrica fiber showed morphological transformations, thermal stability and chemical resistance. The adsorption potential of modified fiber was investigated using adsorption isotherms for hazardous congo red dye removal from aqueous system. The maximum adsorption capacity of dye onto grafted Luffa cylindrica fiber was found to be 17.39mg/g with best fit for Langmuir adsorption isotherm. The values of thermodynamic parameters such as enthalpy change, ΔH0 (21.27kJ/mol), entropy change, ΔS0 (64.71J/molK) and free energy change, ΔG0 (−139.52kJ/mol) were also calculated. Adsorption process was found spontaneous and endothermic in nature.

Removal of Cu(II) by loofah fibers as a natural and low-cost adsorbent from aqueous solutions

As a natural and low-cost material, loofah fibers were applied as an adsorbent to remove Cu(II) from aqueous solutions. The effect of adsorption conditions, such as pH, foreign ions, humic substances (HS), contact time and temperature on the Cu(II) removal, were investigated intensively. The adsorption of Cu(II) on loofah fibers was strongly dependent on pH and foreign ions, and the adsorption of Cu(II) was increased in the presence of humic acid (HA) at pH<8.0 but decreased at pH>8.0. The Langmuir and Freundlich isotherm models were used to simulate the adsorption isotherms. The simulated adsorption isotherms, which were obtained from Langmuir and Freundlich isotherm models, showed that both of the two models were applicable to this system. On the basis of the experimental data, the Langmuir isotherm model could fit it better according to linear correlation coefficient (R2). The optimum kinetics of adsorption was found to fit the pseudo-second-order kinetic model. The values of ∆H° and ∆G° indicated that the adsorption process was exothermic and spontaneous.

Fabrication, Characterization, and Evaluation of Luffa cylindrica Fiber Reinforced Epoxy Composites

Because of the increasing awareness of the environment and energy issues, as well as advances in technology, the areas of application for annual plant fiber functional materials are expanding. In this work, two chemical treatments, alkalization (2 h agitation with 5% NaOH) and furfurylation (graft furfuryl alcohol followed by oxidation with (1N) NaClO2 solution), were conducted on Luffa cylindrica fiber surfaces. The grafting of furfuryl alcohol followed by oxidation-generated quinines showed better results than alkaline treatment with respect to enhancement of surface area and hydrophobicity as well as wax, lignin, and hemicellulose extraction. The efficiency of chemical treatments was verified by elemental analysis and FTIR spectroscopy. Differential scanning calorimetry, thermo-gravimetric analysis, scanning electron microscopy, water absorption, and mechanical tests were performed to determine the thermal, mechanical, and morphological properties of untreated and chemically treated luffa fiber reinforced epoxy composites. Microstructures of the composites were examined to determine the mechanisms for the fiber-matrix interaction, which affects the thermal stability, water absorption, and mechanical behavior of the composites. The data from the water absorption process of composites at various temperatures were analyzed using a diffusion model based on Fick’s law.

Engineered bifunctional enzymes of endo-1,4-β-xylanase/endo-1,4-β-mannanase were constructed for synergistically hydrolyzing hemicellulose

Abstract Xylanase and mannanase were widely used in various application fields for degrading hemicellulose. The coordinated action of them could significantly improve hemicellulose hydrolysis. To enhance the synergistic action of xylanase and mannanase on hemicellulose, twelve chimeras of xylanase and mannanase were constructed and expressed in Pichia pastoris . The data presented that the types of peptide linker, the length of linker and the integration order of two enzymes had great effects on the properties of chimeras and synergistic efficiencies toward the hydrolysis of luffa cylindrica fiber. The chimera XE 3 M, with rigid α-helix-forming peptide A[EAAAK] 3 A as linker and xylanase at the N-terminal, greatly improved the hydrolysis of luffa cylindrica fiber. It revealed that the synergistic action of xylanase and mannanase on hemicelluloses could be strengthened by constructing proper chimeras. And it would be useful for developing an economical process for hemicellulose hydrolysis.

Effect of the Loofah-fibers on the mechanical properties of Polymer Concrete

Polymer Concrete was reinforced with Loofah fibers in order to improve the compressive and flexural strength. Polymer concrete specimens were prepared with 70% of silicious sand, 30% of polyester resin and various fiber concentrations (0.3, 0.6 and 0.9 vol%). The results show decrease in the values of mechanical properties including flexural strength, compressive strength and compression modulus of elasticity.

Adsorption of phenol from aqueous solutions by Luffa cylindrica fibers: Kinetics, isotherm and thermodynamic studies

The present study is concerned with the removal of phenol from aqueous solution by adsorption onto low cost adsorbent. Luffa cylindrica fibers, LC, were investigated as an adsorbent for the removal of phenol. Batch adsorption experiments were performed as a function of pH, contact time, phenol concentration, adsorbent dose and temperature. The optimum conditions for maximum adsorption were attained at pH 7, LC dose of 3g/L. Langmuir, Freundlich, Tempkin and Dubinin–Radushkevich isotherm models were selected to evaluate the adsorption of phenol on LC. It was found that the Langmuir isotherm model best fits the phenol adsorption onto LC. The pseudo-second-order rate equation as well as the micropore diffusion model described the kinetic data well. The adsorption process was found to be an exothermic process. Thermodynamic parameters of phenol adsorption were calculated. The FT-IR analysis confirms that the adsorption of phenol on LC has a good and favorable adsorptive capacity.

Immobilization of TiO2 nanoparticles on natural Luffa cylindrica fibers for photocatalytic applications

TiO2/Luffa composites have been successfully prepared via a sol–gel method from the hydrolysis of a precursor of TiO2. The possibility to use Luffa fibers as biotemplate to self-support hierarchical TiO2 macrostructures has also been tested with success. The photocatalysts and the TiO2/Luffa composites were characterized by X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, FT-IR, and UV-visible spectroscopy. The photocatalytic activities have been investigated in the photodegradation of methanol, chosen as model molecules for VOCs in air. The reactions have been followed by IR-operando spectroscopy. TiO2/Luffa composites exhibited a good stability and photocatalytic activity under UV light irradiation, giving rise to a new generation of green photocatalysts, easy to shape and manufacture, for the photodegradation of organic pollutants.

Thermal and mechanical properties of bio-nanocomposites reinforced by Luffa cylindrica cellulose nanocrystals

Cellulose nanocrystals have been prepared by acid hydrolysis of Luffa cylindrica fibers. The acid-resistant residue consisted of rod-like nanoparticles with an average length an diameter around 242 and 5.2nm, respectively (aspect ratio around 46). These cellulose nanocrystals have been used as a reinforcing phase for the processing of bio-nanocomposites using polycaprolactone (PCL) as matrix. To promote interfacial filler/matrix interactions the surface of cellulose nanocrystals was chemically modified with n-octadecyl isocyanate (C18H37NCO). Evidence of the grafting was supported by infrared spectroscopy and elemental analysis. X-ray diffraction analysis was used to confirm the integrity of cellulose nanocrystals after chemical modification. Both unmodified and chemically modified nanocrystals were used to prepare nanocomposites. The thermal properties of these materials were determined from differential scanning calorimetry and their mechanical behavior was evaluated in both the linear and non-linear range.

Morphology and antimicrobial properties of Luffa cylindrica fibers/chitosan biomaterial as micro-reservoirs for silver delivery

Micro-spongy structure of Luffa cylindrica fibers (LCF) coated with chitosan (CS), called micro-reservoir, seems to be an interesting route to promote local silver particle (Ag) delivery. In the present paper, the morphology and the antimicrobial activity of LCF–CS-Ag micro-reservoir were investigated. The LCF–chitosan material (LCF–CS) was successfully prepared by contacting LCF with hydroxide sodium solution followed by an acetic acid treatment of chitosan. Scanning electron microscopy pictures (SEM–EDX) showed that the LCF surface was strongly modified by the treatment and confirmed the growth of nanoparticles of silver (NpAg) with a size ranging from 20 to 150nm onto and into the surface of the cell-fibers (CF). The LCF–CS and LCF–CS-Ag biomaterials exhibit antibacterial activities as bacteriostasis zone diameters range from 7 to 15mm against Staphylococcus aureus and from 7.3 to 17mm against Escherichia coli. Furthermore, an inhibitory effect was observed for a relatively long period (18days).

Study of Static Adsorption System Phenol / Luffa Cylindrica Fiber for Industrial Treatment of Wastewater

It is very well known at present that different industries agro-food sector generally produce considerable quantities of wastewater should be treated imperative for preserving the environment, and thus avoid a real danger to the ecosystem. These waters are usually loaded with in pollutants of organic nature. This study was motivated by the fact that no quantitative study concerning the physico- chemical behavior of Luffa cylindrica fibers, hence the idea to use the capacity of retention by adsorption of contaminants. In the first step, we studied the kinetics of adsorption (static adsorption of system phenol/fibers of Luffa cylindrica) by using the model of pollution of the phenol as a method of analysis the UV spectrophotometry, in a second step we valued with quantification the adsorption isotherms obtained in relation to other commonly used isotherms (activated carbon/phenol) and a final step optimization of the phenomenon has been conducted, the results are widely presented and discussed taking into account the variation some physicochemical parameters. This work demonstrates and confirms the possibility of using Luffa cylindrica fibers for industrial treatment of wastewater for its advantageous features: natural fiber, economic, non-toxic, biodegradable, filter, fuel and incinerated,etc

Mechanical Analysis of Bio Nanocomposite Prepared from Luffa cylindrica

Luffa cylindrica (LC), a tropical vegetal product, consists of highly vascular system. It has been modified by calcium phosphate and calcium carbonate separately to produce composites of Ca-salts. The modified form of LC has been reinforced with novolac resin at 30°C to provide cross linked polymer composites. The composites have been further sonicated at 40°C for 1h to produce bio nano composites. The final yield is more than 80% of the raw materials used. The physical and chemical analysis of the composites have been done. Incorporation of resin in to the inner fiber surface of LC which is rich in cellulose is confirmed from ultra-violet spectroscopy (UV), and Fourier transform infrared (FTIR) analysis. Thermal studies of the composites done in an inert atmosphere reveals that the composites decompose within a temperature range of 250 - 550°C. The tensile parameters such as maximum stress, Young's modulus and yield strength were measured. The compressive and flexural strength of the LC fiber- reinforced composites were also studied by varying the weight of fiber in the resin.

Effect of chemical modification of Luffa cylindrica fibers on the mechanical and hygrothermal behaviours of polyester/luffa composites

Effects of surface chemical modifications of luffa fibers on mechanical and hygrothermal behaviors of polyester/luffa composites were studied. Unsaturated polyester resin was used as matrix. Untreated, alkali-treated, treated with combined process, and acetylated luffa fibers were used. Scanning electron microscopy and infrared spectroscopy were used to characterize the morphology and chemical structure of the luffa fibers. The mechanical properties of the composites were characterized using the three-point flexural bending test. Water absorption tests were conducted on both the fibers and the composite materials by immersion in distilled water at 25°C. The acetylation treatment improved the mechanical properties. As shown by infrared analysis, the process decreased the hydrophilic behaviour of the luffa fibers, improving their adhesion to the polyester matrix. The chemical modifications at the surface of the luffa fibers also decreased the diffusion coefficient and the maximum amount of water absorbed by these fibers. Moreover, it was observed that for the fibers tested in this study, the diffusion process was “Fickian” at earlier times of immersion, but became complicated towards the end of the immersion. Similar results have been obtained for composite materials at earlier stages of water immersion. The diffusion process was found to be affected by external loads applied on the exposed composite materials. As the load increased, the amount of absorbed water increased at a higher rate of diffusion.

Luffa cylindrica as a lignocellulosic source of fiber, microfibrillated cellulose, and cellulose nanocrystals

In this work the annual plant called Luffa cylindrica (LC) has been characterized and used to prepare macroscopic lignocellulosic fibers and cellulosic nanoparticles, viz. microfibrillated cellulose (MFC) and whiskers, each of which can be used as a reinforcing phase in bionanocomposites. The morphological, chemical, and physical properties of LC fibers were first characterized. The contents of lignin, hemicellulose, and other constituents were determined, and scanning electron microscopy (SEM) observations were performed to investigate the surface morphology of the LC fibers. Sugars contents were determined by ionic chromatography, and it was shown that glucose was the main sugar present in the residue. MFC and whiskers were prepared after chemical treatments (NaOH and NaClO2), purifying cellulose by eliminating lignin and hemicellulose. Transmission electron microscopy (TEM) and SEM made it possible to determine the dimensions of LC whiskers and MFC. Tensile tests were carried out to investigate the mechanical properties of LF nanoparticles.

The Study of the Effects of Different Chemical Compounds applied on Luffa Cylindrica Fibres with the Help of Ultrasonic Energy

The Study of the Effects of Different Chemical Compounds applied on Luffa Cylindrica Fibres with the Help of Ultrasonic Energy