Luffa Cylindrica Fibers Research Articles

Eco-Composites of Polyurethane and Luffa Aegyptiaca Modified by Mercerisation and Benzylation

New eco-composites were prepared from castor oil polyurethane reinforced with Luffa cylindrica fibres. These fibres were used without treatment as well as after mercerisation and mercerisation/benzylation surface treatments. TG curves of mercerised Luffa showed a small increase in thermal stability, associated with the removal of polyoses and soluble lignin. TG curves of benzylated fibres showed a decrease in thermal stability (Tonset and Tmax.) and an increase in residual carbon due to aromatic ring insertion. FTIR spectra and elemental analysis also confirmed benzylation, and X-ray diffractograms showed a decrease in cellulose crystallinity. The eco-composite (crude fibre) absorbed more water (14% after 4 – weeks' exposure) than the resin, because of the hydrophilic character of natural fibres, but mercerisation and benzylation reduced this value by about 50%. Tensile moduli of composites reinforced with untreated and mercerised fibres were comparable, but increased by 33% with the use of mercerised/benzylated Luffa cylindrica. SEMs of the fibres and fibres-matrix interfaces are presented.

Dye adsorption behavior of Luffa cylindrica fibers

Using natural Luffa cylindrica fibers as adsorbent removal of methylene blue dye from aqueous solutions at different temperatures and dye concentrations was investigated in this study. Thermodynamics and kinetics of adsorption were also investigated. The adsorption isotherms could be well defined with Langmuir model instead of Freundlich model. The thermodynamic parameters of methylene blue (MB) adsorption indicated that the adsorption is exothermic and spontaneous. The average MB adsorption capacity was found out as 49 mg/g and average BET surface area of fibers was calculated as 123 m 2/g.

2616 へちま繊維の引張特性(S23-1 天然繊維の機械的特性,S23 バイオマス由来材料の成型加工と特性評価)

The mechanical properties of loofah fiber are investigated by tensile test. The tensile tests are carried out with loofah fiber of three types at room temperature. Tensile strength and total elongation of a single loofah fiber were about 39MPa and 5%, respectively. Tensile strength and total elongation of strip-type specimens cut off from a loofah fiber were about 25MPa and 10%, respectively. The experimental results show that total elongation of rectangle specimens with complicated structure increases from that of single loofah fiber.

3005 プレス成形によるリグニンとへちまの複合化(S40-2 グリーンコンポジットの機能性評価と新規開発,S40 バイオマス由来材料の成形加工と特性評価)

Aloofah fiber reinforced lignin composite was fabricated to develop a new green composite material. The composite was fabricated using hot pressing method. As the fabrication conditions of the composite, two molding pressure conditions of 16.7MPa and 41.7MPa were chosen for the fabrication at a temperature of 150℃. Bending test was carried out to evaluate the mechanical property. Bending modulus of the green composite increases as the volume fraction of loofah fiber decreases. As a result, it is seen that the bendability of composite plate is improved.

Equilibrium and kinetic studies on the adsorption of surfactant, organic acids and dyes from water onto natural biopolymers

In order to improve the mechanical property of chitosan beads, the powder of loofah fiber was added in chitosan/acetic acid slurry to prepare composite beads with and without freeze-drying. The former was called the dried bead and the latter was the wet bead. The equilibria and kinetics for adsorption of linear alkylbenzene sulfonate, tannic acid, humic acid, and three dyes (reactive, acidic, and basic) onto these two beads were compared at 30 °C. It was shown that the adsorption capacity with the wet bead was generally higher than that with the dried bead. Lumped kinetic analysis indicated that the pseudo-first-order equation could well describe the adsorption processes. On the other hand, the better fit of kinetic data by the Elovich equation instead of by intraparticle diffusion model suggested the significance of chemisorption mechanism during the processes. The parameters of these kinetic models were also evaluated and discussed.

Acetilação da fibra de bucha (Luffa cylindrica)

Neste trabalho, foi analisado o efeito de um tratamento químico, ou seja, de acetilação de grupos, sobre a estrutura e a morfologia superficial de fibras de bucha (Luffa cylindrica) por meio de FTIR e microscopia eletrônica de varredura. Esse tratamento foi realizado tendo por objetivo aumentar a compatibilidade da bucha com as matrizes poliméricas usualmente empregadas em compósitos. Mostrou-se que o tratamento reduziu a polaridade das moléculas de celulose e removeu a camada superficial das fibras de bucha, expondo a sua estrutura fibrilar interna, com conseqüente aumento da área disponível para a adesão.

Graft copolymerization of vinyl monomers bearing positive charges or episulfide groups onto loofah fibers and their antibacterial activity

Graft copolymerization of vinyl monomers bearing positive charges or episulfide groups onto loofah fibers and their antibacterial activity

Graft copolymerization of vinyl monomers bearing positive charges or episulfide groups onto loofah fibers and their antibacterial activity

Ion exchange fibers with quaternary ammonium groups, phosphonium groups, or thiol groups etc., were prepared by graft copolymerization of vinyl monomers on loofah fiber which is one of the natural fibers. Methacryloyloxyethyl trimethyl ammonium chloride (METAC), tributyl-4-vinylbenzyl phosphonium chloride (TRVB), and epithiopropyl methacrylate (ETMA) were used as vinyl monomers. Graft copolymerization of METAC on loofah could be carried out in water using ammonium cerium (IV) nitrate. Graft copolymerization of TRVB and ETMA on loofah could be performed in water and water-dimethylsulfoxide mixed solution using hydrogen peroxide as an initiator, respectively. The optimum conditions for each graft copolymerization were investigated in detail. Ion exchange fibers (LE-TTA) having both thiol groups and triethylenetetramine side chains were obtained by treatment of L-g-ETMA (LE) with triethylenetetramine. LE and LE-TTA had high adsorption ability for silver ions. LE-TTA-Ag exhibited high antibacterial activity against E. Eoli and S. aureus, but LE-Ag did not. On the other hand, L-g-METAC and L-g-TRVB also exhibited high antibacterial activity against E. Eoli and S. aureus. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1077–1086, 2000