Search

This study investigates the mechanical properties of high impact polypropylene composite reinforced with pineapple leaf fibre from the Josapine cultivar as a function of fibre loading. PLF was extracted by using a pineapple leaf fibre machine and then an alkaline treatment was conducted to enhance the properties. Samples of the composite were fabricated with 100 mm fibre length with five different fibre loadings of PLF (30, 40, 50, 60 and 70 wt%). The fabrication was made by a compression moulding technique with unidirectional fibre orientation. Related tests such as tensile, hardness and density tests were conducted to determine the effect of fibre loading. The experimental data showed that the composite with the 60 wt% fibre loading offered the highest value of tensile strength, which was about 309%, and the Young’s modulus was about 540% compared to 0 wt% of PLF loading. Meanwhile, the hardness and density of the PLF/PP composites showed very similar values, with small increments from 30 wt% up to 70 wt% PLF loading compared to 0 wt% of PLF loading. The highest values are 65.38 Shore-D and 1.002 g/cm³ respectively. The results also revealed that PLF from the Josapine cultivar with alkaline treatment greatly influences the mechanical properties of PLF/PP composite. [ABSTRACT FROM AUTHOR]

In this paper, we analyze the results of the delignification treatments performed on three natural fibers (sisal, pineapple, and banana) and of the thermal treatments at 400, 600, and 800°C on three industrial fibers (aramid, carbon, and glass). The fibers were analyzed by TGA, SEM, and EDS, as well as tested for tensile strength before and after the delignification and thermal treatments. Contact angle measurements were also carried out on the natural fibers. With the delignification treatments, the removal of Si, K, and Mg on pineapple and banana fibers was achieved. Thermal treatments lowered significantly the tensile strength of industrial fibers, while delignification treatments decreased slightly the mechanical resistance of natural fibers, except in the case of the pineapple fiber. [ABSTRACT FROM PUBLISHER]

Despite being mechanically and environmentally sound, pineapple leaf fibers (PALF) are of little use in Malaysia and the least studied for composite applications. In this study effects of abrasive combing and simple pretreatments on PALF and their adhesion to vinyl ester were investigated. In pineapple leaves, PALF are present in top lamina as large vascular bundles and bottom lamina as fine strands. Tensile strength and modulus of fine PALF strands are 155% and 134% higher than those of vascular bundles respectively. Abrasive combing reduced PALF diameters by 50.3% resulting in finer bundles with 48.6% higher modulus and 51.5% greater strength without much negative effects on fiber integrity. Water-soak did not change PALF tensile properties significantly, while dilute sodium hypochlorite (NaOCl) solution improved PALF modulus and strength by as much as 123% and 35% respectively while reducing elongation at break by 47%. Dilute solution of NaOCl changed PALF structurally through higher crystallinity and closer packing resulting in increased tensile strength and modulus. PALF thermal stability was also enhanced. PALF-vinyl ester adhesion improved due to bleach pretreatment indicated by significantly reduced fiber pull-out length of broken PALF-vinyl ester composites. Morphological study using scanning electron microscope was used to confirm the findings. This study indicated that abrasive combing and simple pretreatment of dilute sodium hypochlorite are potential techniques to produce cost-effective PALF for reinforcing plastics. [ABSTRACT FROM AUTHOR]

The article presents information on a study which evaluated the performance characteristics of polypropylene (PP)/pineapple leaf fiber (PALF) fiber-reinforced composites filled with organically modified nanoclays. A review of the related literature is given. It describes the fabrication of the nanocomposites using melt blending method in a twin-screw extruder. Variables investigated were change in mechanical properties, crystallization behavior, water absorption and thermal stability.

Abstract: Moisture equilibrium data of pineapple pulp (PP) powders with and without additives – 18% maltodextrin (MD) or 18% gum Arabic (GA) – were determined at 20, 30, 40 and 50°C by using the static gravimetric method in a water activity range of 0.06–0.90. The obtained isotherms were sigmoid, typical type III, and the Guggenhein–Anderson–de Boer (GAB) model was fitted to the experimental data of equilibrium moisture content versus water activity. Addition of additives was shown to affect the isotherms in such a way that, at the same water activity, samples PP+GA and PP+MD presented lower equilibrium moisture content and were not so affected by varying temperature. The net isosteric heats of sorption of pulp powders with additives were higher (less negative) than those of pineapple pulp powders, suggesting that there are more active polar sites in the product without addition of GA or MD. An empirical exponential relationship could describe the heat of sorption dependence on the material moisture content. [Copyright &y& Elsevier]

Natural fibre composites have been prepared by grafting hydrophobic monomer [n-butyl acrylate (BA)] onto chemically modified pineapple leaf fibre (PALF) using a complex initiating system [Cu (11) SO4EDTA/ammonium persulphate (APS)] in an aqueous medium without and with additives [sodium silicate (SS)] and N,N′-methylenebisacrylamide (MBA) as crosslinking agent. The polymerization reaction has been studied at varying temperature, duration, and Cu(II). EDTA. APS and BA concentrations. The overall activation energy of grafting is found to be 19.04 kJ mol-1 and the optimum time period for the reaction is 3h. The chemically modified PALF, crosslinked PALF-g-PBA copolymer and (crosslinked PALF-g-PBA)/SS composites so obtained have been characterized by FT-IR and their morphology studied by scanning electron microscopy. The thermal behaviour and tensile properties of the samples have been studied and compared with their biodegradation and water absorption capacities. It is observed that the composites show more water uptake capacity than the copolymers, making them suitable for use as superabsorbent natural fibre. These composite superabsorbents show lower biodegradability in both sludge water and soil as well as by using cultured microorganisms than the copolymer alone. [ABSTRACT FROM AUTHOR]

Physical characteristics of khimp (Leptadenia pyrotechnica) fibre have been studied and compared with those of the other natural fibres, such as cotton, jute, sunhemp and pineapple. The khimp fibre is lignocellulosic having high α-cellulose (75.26%), and low lignin (4.93%) and pentosan (5.15%) contents similar to sunnhemp, flax and pineapple leaf fibres. The degree of crystallinity (60.0%) of the fibre measured by X-ray diffractometry technique is lower than that of cotton but higher than that of lignocellulosic fibres like jute or sunnhemp. SEM study of the fibre shows that the fibrils are arranged longitudinally. Cross-sectional features studied by SEM reveal that the fibre is multicellular in nature, consisting of 5-6 cells in a fibre. The infrared spectra of khimp fibre show peaks in the regions as observed for lingocellulosic fibre like jute. [ABSTRACT FROM AUTHOR]

Physical and tensile properties of pineapple fibers were characterized. Tensile properties of pineapple fibers, like most natural fibers, showed a large variation. The average interfacial shear strength between the pineapple fiber and poly(hydroxybutyrate-co-valerate) (PHBV) was 8.23 MPa as measured by the microbond technique. Scanning electron microscopy (SEM) photomicrographs of the microbond specimens revealed an adhesive failure of the interface. Fully degradable and environment-friendly “green” composites were prepared by combining pineapple fibers and PHBV with 20 and 30% weight content of fibers placed in a 0°/90°/0° fiber arrangement. Tensile and flexural properties of these “green” composites were compared with different types of wood specimens. Even though tensile and flexural strength and moduli of these “green” composites were lower than those of some wood specimens tested in grain direction, they were significantly higher than those of wood specimens tested in perpendicular to grain direction. Compared to PHBV virgin resin, both tensile and flexural strength and moduli of these “green” composites were significantly higher. SEM photomicrographs of the fracture surface of the “green” composites, in tensile mode, showed partial fiber pull-out indicating weak bonding between the fiber and the matrix. [ABSTRACT FROM AUTHOR]