Sisal Fiber Reinforced Polyester Composites Research Articles

Effect of alkali and silane treatment on water absorption and mechanical properties of sisal fiber reinforced polyester composites

The present work deals with the effect of water absorption on the mechanical properties of untreated, 10% alkali-treated, and 10% alkali plus 1% silane treated sisal fibers (5%, 10%, and 15%) reinforced polyester composites. Hand lay-up was used to create the composite. The samples were prepared in accordance with ASTM standards, and tests for tensile strength, flexural strength, impact strength, and water absorption were performed. An increase in the tensile, flexural and impact strength was observed with an increase in fibre loading for untreated, alkali-treated and alkali plus silane treated sisal fibre reinforced polyester composites without water absorption, the increase being maximum for 10% alkali plus 1% silane treated fibre composite. Water absorption reduces tensile strength while increasing flexural and impact strength in untreated sisal fiber reinforced composites. There is an increase in tensile, flexural, and impact strength with higher fiber loading for 10% alkali-treated and 10% alkali-treated plus 1% silane treated sisal fiber reinforced polyester composites with and without water absorption. The tensile, flexural, and impact strength of alkali plus silane treated fiber is maximum at any given fiber loading, indicating that the alkali plus silane treatment is effective in improving the fiber matrix interface. Water absorption increases with fiber loading in untreated, 10% alkali-treated, and 10% alkali plus 1% silane treated sisal fiber reinforced polyester composites, with the rate being lowest in alkali plus silane treated fiber reinforced composites.

Effects of Chemical Treatment, Hybridization, and Hybrid Fiber Stacking Sequence and Orientation on Tensile and Impact Strength of Continuous Sisal Fiber Reinforced Polyester Composites

ABSTRACT This paper has presented the enhancement of tensile and impact strength of continuously aligned sisal fiber reinforced polyester composites through chemical treatment and hybridization. Sodium hydroxide (NaOH) and baking soda (NaHCO3) were used for sisal fiber treatment. Comparisons on the effect of sodium hydroxide and baking soda treatments on tensile and impact strength of the composites were performed. Unidirectional glass and carbon fibers were selected as hybrid fibers. Nineteen laminates were prepared as per the standards. The laminates were made of pure sisal fiber and hybridized with glass or carbon fibers at different stacking sequence, orientation, and volume fraction. The effects of glass and carbon fibers hybridization on tensile and impact strength of the composites were studied and compared. Further enhancements on the tensile and impact strength of the composites were investigated through alterations on the stacking sequence, orientation, and volume fraction of the hybrid fibers. Symmetric hybrid composites which avoided sisal/sisal plies interface have shown more than 95% and 130% rise in their tensile strength by adding about 8% volume of glass and carbon fibers respectively. Moreover, with only about 8% carbon fiber inclusion in the laminates, almost 60% improvements in the impact strength were discovered.

DIELECTRIC STRENGTH ANALYSIS OF ACACIA NILOTICA WITH CHEMICALLY TREATED SISAL FIBER REINFORCED POLYESTER COMPOSITE

This work focuses on utilizing the chemically treated and untreated sisal fiber along with Acacia Nilotica as a secondary reinforcement in the polyester matrix. Composite specimens were prepared by using different volume percentage of the reinforcements. Dielectric properties of untreated and NaOH, KMnO4, C18H36O2 and C4H6O5 treated sisal fiber reinforced polyester composites were studied initially. Test results have shown that the composite material incorporated with 20% v/v treated sisal fiber has higher dielectric strength. Further investigations were carried out on the effect of the Acacia Nilotica natural filler in the Dielectric and water absorption properties of the sisal fiber/ polyester composite. The Composites were fabricated by incorporating the Acacia Nilotica filler in 5, 10, 15 and 20 volume percentages with the NaOH treated sisal fiber reinforced polyester composite. It is found that the addition of natural filler and surface treatment enhanced the dielectric properties of the composites.

Statistical Analysis and Pattern Search Optimization on the Impact Properties of Talk Particulates Impregnated Sisal Fiber Reinforced Polyester Composites

This investigation is aimed at studying the effect of talk particles impregnation on the impact properties of sisal fiber reinforced polyester composites. The composite sheets were fabricated using compression molding machine by varying the curing temperature (60, 80 and 100 °C) and particulate weight content (ranging from 5 to 25 %) in the composites. The influences of curing temperature and talk weight content on the impact strength of the composites were experimentally determined and the fracture mechanisms of the composites were studied using scanning electron microscope. Statistical analyses were made on the obtained experimental values and mathematical model was developed to correlate the relationship between fabrication parameters and impact strength of the composites. Pattern search optimization technique was used to optimize the impact strength of the talk particles impregnated sisal fiber reinforced polyester composites. The values were found to be significant and the investigation resulted with effective improvement in the impact strength of the talk particles impregnated sisal fiber reinforced polyester composites.

Fatigue in Sisal Fiber Reinforced Polyester Composites: Hysteresis and Energy Dissipation

Natural fibre reinforced polymer biocomposites (NFPBCs) constitute an important branch in the field of green composite materials. The work describes the fatigue behaviour of polyester biocomposites reinforced with natural sisal fibres and stacked as cross laminates with [0/90]s sequence Three-point bending static and cyclic tests have been used to investigate the fatigue behaviour of these particular bio-reinforced composites. The cyclic tests have been carried out at 1.5Hz of frequency using a sinusoidal waveform and loading levels varying between rd = 0.55 to 0.95 and the curves of stiffness degradation (F/F0) has been plotted. Failure is reached after the first few cycles for high loading levels, whereas for low values of rd (0.55) fracture is only partial, even after reaching one million of cycles.

Electrical properties of short sisal fiber reinforced polyester composites fabricated by resin transfer molding

The electrical properties of sisal fiber reinforced polyester composites fabricated by resin transfer molding (RTM) have been studied with special reference to fiber loading, frequency and temperature. The dielectric constant (ε′), loss factor (ε″), dissipation factor (tanδ) and conductivity increases with fiber content for the entire range of frequencies. The values are high for the composites having fiber content of 50vol.%. This increment is high at low frequencies, low at medium frequencies, and very small at high frequencies. The volume resistivity varies with fiber loading at lower frequency and merges together at higher frequency. When temperature increases the dielectric constant values increases followed by a decrease after the glass transition temperature. This variation depends upon the fiber content. Finally an attempt is made to correlate the experimental value of the dielectric constant with theoretical predictions.

Dynamic mechanical properties of sisal fiber reinforced polyester composites fabricated by resin transfer molding

AbstractThe dynamic mechanical properties of sisal fiber reinforced polyester composites fabricated by resin transfer molding (RTM) were investigated as a function of fiber content, frequency, and temperature. Investigation proved that at all temperature range the storage modulus (E′) value is maximum for the composites having fiber loading of 40 vol%. The loss modulus (E″) and damping peaks (tan δ) were lowered with increasing fiber content. The height of the damping peaks depends upon the fiber content and the fiber/matrix adhesion. The extent of the reinforcement was estimated from the experimental storage modulus, and it has been found that the effect of reinforcement is maximum at 40 vol% fiber content. As the fiber content increases the Tg from tan δ curve showed a positive shift. The loss modulus, storage modulus, and damping peaks were evaluated as a function of frequency. The activation energy for the glass transition increases upon the fiber content. Cole–Cole analysis was made to understand the phase behavior of the fiber reinforced composites. Finally, attempts were made to correlate the experimental dynamic properties with theoretical predictions. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

Tensile Properties of Sun Hemp, Banana and Sisal Fiber Reinforced Polyester Composites

Experiments are conducted to find out the tensile properties of short sun hemp, banana, and sisal fiber reinforced composites. Length of these natural fibers and fiber weight are varied and are impregnated in polyester resin to prepare tensile test specimen. Optimum values of fiber length and fiber weight ratios are found through experimental results. Analysis is done on these results.