Fiber Tensile Strength Research Articles

Effect of mechanical and chemical treatments of arecanut (areca catechu L.) fruit husk on husk and its fibre

Arecanut husk, a biomass is generated during extraction of nut and is stored in heaps in the backyards of processing units. Arecanut husk presently has no industrial/commercial applications and is a cause of major environmental hazards. Arecanut husk is rich in good quality lingo-cellulosic fibres which have potential applications in various fields. Presently there is no proper process and machinery available to extract these fibres on a mass scale. Designing such machinery requires characterisation of husks, bonding force between fibres and the shell, etc. The aim of the present study is develop suitable mechanical and chemical treatments to facilitate easy extraction of fibres and also to study the effects of theses pretreatments on tensile property of fibres. The variety used was Shreevardhini. It was noticed that the pretreatments of husk had significant effect on fibre separation. Highest fibre recovery of about 57% was achieved with pressed husks soaked in water for 24 h. Detachment force required for fibre / fibres separation from husk was least in 2.5% KOH treated husks. There was no adverse effect of pretreatments on tensile strength of fibres. Pressing of husks resulted in maximum fibre recovery due to weakening of bonds, hence pressing of arecanut husk before mechanical fibre extraction is recommended, whereas chemical pretreatment of husks with KOH is not recommended.

Effect of basalt, polypropylene and macro-synthetic fibres on workability and mechanical properties of self-compacting concrete

In this study, the effects of different fibre types on the workability and mechanical properties of self-compacting concrete were investigated. Fresh and hardened properties of self-compacting concrete, different fibre content 0.90, 1.35 and 1.80 kg/m3 were evaluated using basalt, polypropylene and macro synthetic fibres with different fibre lengths of 24, 19 and 40 mm, respectively. The properties of fresh concrete were evaluated in terms of slump flowing, viscosity and flowability. In addition, compressive, flexural and splitting tensile strength were obtained from hardened concrete properties. To characterize mechanical properties 90 specimens were experimentally tested. The results show that the use of fibre reduces the workability of self-compacting concrete. On the other hand, tensile and flexural strength of the self-compacting fibre reinforced concrete increased with increasing fibre content, but it was determined that the fibre addition had no significant effect on the compressive strength.

Recycling of Commercial E-glass Reinforced Thermoset Composites via Two Temperature Step Pyrolysis to Improve Recovered Fiber Tensile Strength and Failure Strain

Economic and regulatory pressures on the global composites industry have encouraged the research and development of technology for the recycling of fiber reinforced polymer composites. Although significant advancements have been made in the recycling of carbon fiber composites, more progress is needed in the recovery of glass fibers, which make up the overwhelming volume of the composites market. In this study, wind turbine blades and automotive sheet moulding compound (SMC) were subjected to a two temperature step pyrolysis. This multistep process yielded improvements in the recovered E-glass fiber’s tensile strength, by as much as 19%, and strain to failure, by as much as 43%, over a single high temperature step pyrolysis. Despite these gains, pre-pyrolysis fiber measurements indicate that pre-existing damage may inherently limit the quality of glass fiber recoverable from pyrolysis without any post processing.

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.

Effect of alkali treatment of lower concentrations on the structure and tensile properties of Pakistan’s coarse cotton fibre

Cotton fibres of high Micronaire values are known to have inferior spinning performance. Either reduction of fibres’ fineness or increase in tensile strength is generally expected to improve the spinnability of fibres. In this piece of research, the effects of alkali treatment at lower concentrations (0.75–2.25M) and higher temperatures (70–100 °C) on the cross-section of cotton fibre and on the tensile strength have been investigated. Observations were made using scanning electron microscopy (SEM) and single fibre tensile strength testing. It was found that the roundness of the fibre cross section was improved and the tensile strength of the fibres also increased after treatment with alkali at lower concentration (0.75 M) and relatively lower temperature (70 °C). It is proposed that such changes occurred due to possible cellulose dissolution/transformations. It was thus concluded that the alkali treatment of cotton fibres at lower concentrations (0.75 M) and 70 °C for a shorter period of time (45 mins) could lead to improvement in tensile strength and roundness of fibre cross-section, thereby improving micronaire.

Physical Characterization of Eri Silk Fibers Produced in Kenya

ABSTRACT Eri silk produced in Kenya was characterized for sericin content, moisture content, surface morphology, thermal properties, functional groups, crystallinity, and single fiber tensile strength. It was found that Kenyan Eri silk possesses comparable physical properties to those of commercial silk producing countries. At a degummed tensile strength of 6.81cN, Kenyan Eri silk had comparable strength despite having low crystallinity (29.2%). This is an indication that on optimizing rearing procedures and practices of Eri silkworms to certain regions of Kenyan environment, better quality silk fibers can be produced that are competitive in the world market.

Evaluation of the effects of β-tricalcium phosphate on physical, mechanical and biological properties of Poly (3-hydroxybutyrate)/chitosan electrospun scaffold for cartilage tissue engineering applications

ABSTRACTScaffold designing for cartilage tissue engineering requires suitable physico-mechanical and biological properties. This research was carried out to study the effects of β-tricalcium phosphate nanoparticles (β-TCP) on Poly (3-hydroxybutyrate) (PHB)-chitosan (Cs) electrospun scaffold. Results showed that the addition of different amounts of β-TCP increased fibre diameter, porosity, hydrophilicity and tensile strength in the proper condition. An increase in the degradation rate was observed by an increase in the amount of β-TCP. The biological behaviour of the PHB-Cs/7.5%wt β-TCP electrospun nanocomposite scaffold was investigated through the formation of apatite-like granules and proper attachment and proliferation of chondrocytes on the surface of scaffolds.

Analysis of bamboo mechanical properties as construction eco-friendly materials to minimizing global warming effect

Burning fossil fuels increases the amount of carbon dioxide in the atmosphere. Carbon dioxide is the main cause of the greenhouse effect and global warming. Climate change causes an increase in the number of human deaths due to diseases and natural disasters. In general, in the past decade there has been deforestation of 13 million ha / year. The highest deforestation rates (> 3.4 million ha / year) occur in South America and Africa while in Asia also experience deforestation in many places. Bamboo forests are very important especially in East and Southeast Asia as well as in Africa. The potential of bamboo is very large in controlling soil erosion, water conservation, land rehabilitation and carbon sequestration. In carbon sequestration bamboo contributes very significantly. The use of bamboo as an environmentally friendly construction material is very important to do. Testing of bamboo mechanical properties based on ISO 3129-1975 standards, which includes testing of fiber parallel compressive strength, parallel fiber shear strength, fiber parallel tensile strength and straight fiber tagak flexural strength. Setting-up testing is carried out after each specimen in the condition of the kiln dry water content is in the range 12-13% according to the requirements of the ISO 3129-1975 standard. Analysis of variants (Anova) of pressure treatment on bamboo material has an effect on some of the mechanical properties of bamboo. Pressure treatments up to 2.5 MPa have a significant effect on the elastic modulus, tensile strength and shear strength of bamboo while the compressive strength is not significantly affected by the pressure treatment of bamboo material. Bamboo forests have a big influence in reducing the impact of global warming and climate change.

Facile preparation of hyperbranched polysiloxane‐grafted carbon fibers with improved interfacial strength of silicone resin composites

AbstractNew hybrid carbon fibers (CFs) were facilely prepared via in situ synthesizing hyperbranched polysiloxane with epoxy groups onto the fiber surface with the aim to enhance interfacial strength of composites. CFs were grafted with phenyl amine groups through an aryl diazonium reaction, and then modified with hyperbranched polysiloxane obtained by the sol‐gel polymerization of γ‐glycidyloxypropyltrimethoxysilane. Surface structures of different CFs were characterized by Raman spectroscopy and X‐ray photoelectron spectroscopy, indicating the successful modification. The introduced hyperbranched polysiloxane enhanced fiber roughness, polarity, wettability, and surface free energy. Hence, the interfacial shear strength and impact toughness of polysiloxane modified composites (CF‐g‐Polysiloxane) increased sharply compared with those of untreated composites. Moreover, Interfacial reinforcing and toughening mechanisms have also been studied, and polysiloxane modification maintained fiber tensile strength. The obvious improvement of anti‐hydrothermal aging behaviors after modification could be due to the introduction of strong SiOSi bonds at the interface.

Enhanced wettability and adhesion of carbon fibers with polyimide resin interfaces via grafted modified SiO2 nanoparticles

ABSTRACTFunctionalized modified SiO2 was prepared by a mild and simple dip coating method, and a layer of functionalized modified SiO2 coating was introduced onto the carbon fiber surfaces not only to improve the surface wettability and activity of carbon fiber, but also strengthen the interphase of the carbon fiber/polyimide composite. The successful functionalization of SiO2 by bis[3-(triethoxysilyl)propyl] tetrasulfide (TESPT) silane was confirmed. Moreover, a uniform coating with well-dispersed particles on a carbon fiber surface was achieved with a 1.0 wt% addition of TESPT-modified SiO2 (TESPT@SiO2) particles. Under this condition it was observed that the interlaminar shear strength (ILSS) and interfacial shear strength (IFSS) augmentation was 26.37% and 38.27%, respectively, in comparison with carbon fiber composite coated only with polyimide resin. The functionalized modified SiO2 coating could effectively heal the surface defects of fiber, and the fiber tensile strength increased by more than 10.61%. This study provides a scalable, simple, and cost effective method of simultaneously increasing the interfacial strength of composites.

Effects of alkali and steaming on tensile strength of aren (arenga pinnata) fiber

The aim of this research is to investigate the alkali treatment and steaming influence on mechanical properties of Aren frond fiber. The presence of surface impurities and the large amount of hydroxyl groups makes natural fiber less compatible for composite materials reinforcement. Effort to remove the impurities can be done by few treatment that consist of physical, chemical and mechanical treatment. First, Aren frond single fiber were subjected to alkali treatments with 1%- 5% NaOH for a period of 4 - 7 hours to room temperature and followed by steaming 1 - 2 bar in pressure. Treatment of alkali and alkali-steaming combination can increase cellulose content. The tensile tests showed that the alkali and steaming treatment combination resulted the highest tensile strength of Aren frond fiber by 512 MPa. Then the impurities in surface fiber single effect interfacial stress and tend decrease bonding strength. These results show that the combination of alkali treatment and steaming can increase mechanical properties of Aren frond fiber.

Prediction of dynamic increase factor for steel fibre reinforced concrete using a hybrid artificial intelligence model

Steel fibre reinforced concrete (SFRC) has been increasingly used in the engineering structures subjected to intense dynamic loads. In structural design and analysis, a dynamic increase factor (DIF) has been usually used to characterize strain-rate effect on the dynamic mechanical behaviour of SFRC. At present, several analytical equations that contain one or two variables have been utilised to predict the DIF values for material strengths of SFRC. However, this may lead to unsatisfactory results as the rate sensitivity of SFRC is influenced by multiple variables. In this study, a hybrid model, integrating random forest (RF) technique and firefly algorithm (FA), is proposed for predicting DIF values for SFRC. RF is utilized to discover the non-linear relationship between the influencing variables and DIF, while FA optimizes the hyper-parameters of RF. A total of 193 and 314 DIF data samples for compressive and tensile strengths of SFRC are retrieved from the reported studies to train and verify the proposed model. The input variables for the predictive model include strain rate, matrix strength, fibre dosage, and fibre properties (i.e. fibre shape, fibre aspect ratio and fibre tensile strength). The predicted results denote that the developed model is an efficient and accurate method to predict the DIF values for SFRC. Additionally, the relative importance of each input variable is investigated. It is found that the DIF values of SFRC are most sensitive to the matrix strength.

Evaluation of Tensile Strength of Fibers Extracted from Banana Peels

ABSTRACT Tensile properties of banana fibers extracted from the peel of the fruit of the Cavendish sub-group were studied. A total of 43 fibers were manually extracted from the peel of green bananas, measuring five diameters from each fiber. The fibers were examined under the optical microscope up to a 50× magnification and their cross-sectional area (CSA) was observed. Tensile tests were conducted on the extracted banana fibers and Young’s modulus was calculated using apparent area from microscopy observations, then calculating a fiber area correction factor (FACF) to reduce the relevant error. Geometry and extent of the lumen were also measured.

Effect of Alkalization Treatment on The Tensile Strength and Interface Character Matrix-Fibber of Bamboo Petung (Dendrocalamus Asper) Reinforced Polyester Resin Composite

The purpose of this study is to determine the alkalization process effect of bamboo petung fiber (Dendrocalamus Asper) on the Tensile strength of Polyester composite reinforced with bamboo petung fiber. The alkalization process is expected to increase the bond between the automatic and the fiber which in turn can increase the tensile strength of the composite. In this study NaOH was used as an alkaline substance. NaOH is an alkali commonly used as a substance for the alkalization process in various natural fibers for natural composite reinforcing material. Alkalization was done by soaking the fiber into NaOH solution at room temperature and time variation for 1 hour, 2 hours, and 3 hours. After the alacalization process, the fiber was processed to be made into a composite with a polyester matrix with the direction of unidirectional fiber orientation. The process of making composites used vacuum infusion method. Before being used as reinforcing fibers, petung bamboo fiber composites were tested for single fiber tensile strength both after alkalization treatment and fiber before alkalization process. Composite tensile testing was conducted on all variations of both composites with fibers before Alkalization and composite after the alkalization process by using ASTM D638-03 standard. Scaning Electronics Microscope (SEM) was also conducted to observe the morphology of fibers before and after alkalization, besides that SEM was also used to determine the fracture shape of polyester composite reinforced with bamboo petung fiber. From the Tensile testing conducted on single fiber and composite, it was obtained results that either the single fibers strength or composites decreased with increasing NaOH soaking time.

Effect of Different Pressures on Microstructure and Mechanical Performance of F-III Fibers in Supercritical Carbon Dioxide Fluid.

F-III fibers were treated at different pressures in supercritical carbon dioxide fluid and all samples including untreated and treated F-III fibers were characterized by a mechanical performance tester, wide-angle X-ray scattering and small-angle X-ray scattering. By studying the relationship between mechanical performance and microstructural changes of the samples, it was found that microstructural change was the main cause of variation in mechanical performance. Results revealed that the maximum tensile strength and modulus of F-III fibers were acquired at 14 MPa within the pressure range of 8 MPa to 16 MPa when the temperature, tension and time were 250 °C, 6 g·d−1 and 40 min, respectively. Correspondingly, the microstructures of the samples, including the phase fraction, crystal size, orientation factor, fibril radius, fibril length and misorientation angle, have been investigated. It was fortunate that the supercritical carbon dioxide fluid could be used as a medium during the hot-stretch process to improve the mechanical performance of F-III fibers, although the treatment temperature was lower than the glass transition temperature of the F-III fibers.

The effect of self-synthesized hydroxyl-terminated hyperbranched polymer interface layer on the properties of carbon fiber reinforced epoxy composites

A simple and green method to functionalize carbon fiber (CF) with hydroxyl-terminated hyperbranched polymer (HTHBP) synthesized directly through one-pot condensation polycondensation between isophorone diisocyanate (IPDI) and tris (hydroxymethyl) aminomethane (TOAM) was reported. The covalent grafting of HTHBP on the CF surface can greatly increase the polar functional groups, roughness and wettability of CF surface, thereby resulting to significant enhancement of interfacial properties of composites. After grafting, the interlaminar shear strength (ILSS), interfacial shear strength (IFSS) and impact strength of CFs/epoxy composites increased from 58.6 to 81.8 MPa, 48.8 to 87.8 MPa and 55.7 to 76.9 kJ·m−2, respectively. Furthermore, this surface functionalization process could remedy the single fiber tensile strength. The interfacial reinforcing mechanism was also revealed by analyzing interfacial microstructure. This research provided a thought that constructing a continuous gradient modulus interphase layer with strong physicochemical interaction and good wettability by a simple and green method, which could reinforce the interfacial performance and have a bright prospect application in high-performance composite.

Effect of Volume Fraction and Resin System on Tensile, Compression and Flexural Strength of Electrical Glass Fiber Reinforced Plastic Laminate

This work deals with the experimental studies on effect of changing volume fraction and also various resin systems like Epoxy LY556, AW106 & CY230 on ultimate tensile, compression and flexural strength of a polymer matrix composite. The specimens were prepared through vacuum assisted resin transfer molding technique. The vacuum pump is a double stage rotary vacuum pump of specifications 300 lpm, 1 hp &3ph. Reinforcements of different thickness/layer of bidirectional e-glass fibers were used and the epoxy resins of varying viscosities were used. The machining of the fabricated specimens was carried out using abrasive water jet cutting facility. The test coupons were tested as per ASTM standards. Tensile, compression and flexural tests were carried out for each experiment and three trials were made for each experiment in order to arrive at the average value of tensile, compressive and flexural strength. The inferences are drawn for each type of resin system and volume fraction of the matrix and reinforcement used which helps in understanding the enhancement in ultimate strength of the test coupon under study.

Physical characterization of the hair of Mexican women.

Hairs collected from 257 Mexican women, residing in Mexico City, were characterized by instrumental measurements for comparison to more-commonly reported Caucasian, Asian and African hairs. Subjects were subdivided into five age groups and their hairs were characterized by fibre dimension, shape and tensile strength. Results show that Mexican hair appears to be intermediate of Asian and Caucasian hair in diameter and cross-sectional ellipticity. Such findings seem in line with the early and late ethnic origins of Mexican people. Results also illustrate and confirm the large intra- and inter-individual variability within any single hair property. Unexpectedly high levels of hair tensile damage were sometimes encountered.

Factors governing the tensile strength of basalt fibre

Basalt fibre has attracted great attention in developing fibre-reinforced polymers (FRP) in recent years. The tensile strength of basalt fibre is one of the most important considerations when formulating FRP structures. In this study, the strength of seven commercial basalt fibres was studied and compared, and the factors governing the strength of these fibres were investigated. The results showed that the strength of fibre is mainly dominated by the elemental composition of material and sizing on fibre surface, which functioning as “backbone” and “clothing” for the filament, respectively. Correlations between the tensile strength of fibre as a function of Al2O3 content and Fe3+/Σ(Fe3++Fe2+) in the material were also established. Interestingly, as a processing step after fibre spinning, the sizing can increase the strength of material by up to 25%, illustrating the importance of such post-treatment for developing high performance basalt fibres.

Effect of Alkali Treatment on Interfacial and Mechanical Properties of Kenaf Fibre Reinforced Epoxy Unidirectional Composites

Kenaf fibres demonstrate enormous potential in fibre reinforced composites with the excellent performance and environmental benefits. In this work, kenaf fibres were treated with NaOH at the concentrations of 1%, 2%, and 3%. Effects of the alkaline treatments on the mechanical properties of fibre and interfacial shear properties (IFSS) of the resulted composites were systematically evaluated. In addition, relationship between tensile strength and surface friction coefficient of kenaf fibre was shown. Relationship between tensile strength of fibre and IFSS of composites were explored. They were conducted by correlation analysis method. The results indicated that after NaOH treatment, kenaf fibres has increased in tensile strength, surface roughness, friction coefficient, but decreased in diameter. Tensile properties, flexural properties and water absorption of unidirectional kenaf fibre reinforced epoxy resin composites have improved. IFSS of composite treated at 2% alkali has increased by 10.34%, compared to composites untreated fibres. Correlation analysis indicated that there was no significant correlation between kenaf fibre tensile strength and IFSS of the composite. On the other hand, there was significant correlation between kenaf fibre surface friction and the IFSS of the composite with the correlation coefficient of 0.905.