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1.
Sugar palm fiber is one of the most abundant natural fibers used in biocomposites. However, prediction of the mechanical properties of such natural fiber reinforced composites is still challenging. Most of the theoretical modelings are based the micromechanical method. There have been little studies involving statistical approach for prediction of mechanical properties of natural fiber reinforced composites. In this study, the tensile properties of short sugar palm fiber-reinforced high impact polystyrene (SPF-HIPS) composites obtained by means of statistical approach were investigated and compared with the experimental observations and with micromechanical models available in the literature. Statistical approach was used to predict the performance of the composite part with different fiber loadings. A two-parameter Weibull distribution function was used to model the fiber length distribution in the composite. For the experimental validation, the composites were prepared by hot compression technique for different fiber loadings (10 %, 20 %, 30 %, 40 % and 50 % by weight). Tensile testing of the composites was carried out according to ASTM D638 to obtain the composites tensile strength and modulus of elasticity. Experimental results showed that the tensile strength of the composite reduced due to the addition of sugar palm fibers, whereas the elastic modulus increased by a factor of up to 1.34. The current statistical model predicted the tensile properties of SPF-HIPS composite close to the experimental values. It was found that statistical approach with standard micromechanical models can be used to predict the mechanical properties of sugar palm fiber reinforced HIPS composites. Hence, this study could assist in decisions regarding the design of natural fiber reinforced composite products. 相似文献
2.
Organic fiber from animal waste was used for the development of environmentally friendly animal fiber based polyester composites using cow hair. The cow hair fibers were cut into 10 mm lengths to produce the needed short fiber for random dispersion in the matrix. Before use, some of the fibers were treated with sodium hydroxide for fiber surface modification while some were left as untreated. Composites were developed using predetermined proportions of the fibers in an open mould production process. Samples were formed into tensile and flexural shape in their respective moulds and were stripped off the moulds after curing while further curing was ensured for 27 days before testing. Tensile and flexural properties of the cow hair fiber reinforced polyester composites were evaluated from which it was discovered that the untreated fiber reinforced composites possess better enhancement of mechanical properties compared to the treated fiber reinforced composites and the unreinforced polyester material. Mathematical models for the tensile and flexural properties were developed using statistical packages and estimation using developed software. The developed models revealed high degree of correlation between the experimental values and the predicted values. This denotes that the models can be used to predict the mechanical properties of cow hair reinforced polyester composites for various reinforcement contents. 相似文献
3.
There have been many interests in using natural fibers as substitutes for glass fibers to prepare fiber reinforced composites.
Flax fibers, due to their specific strength, have been a hot issue in this field. The focus of this research work is to manufacture
flax fiber reinforced low melting point PET composites directly from nonwoven mats. No consolidation methods are applied to
the carded nonwoven mats before the hot-press molding. The effects of operating parameters like carding method, molding temperature,
molding time, etc. on the mechanical properties of composites have been investigated. Results show it is a facile and cost-saving
method to produce composites specifically in the application areas like automobile interior ornament and decoration materials,
etc. 相似文献
4.
Fiber reinforced polymer composites have played a dominant role for a long time in a variety of applications for their high
specific strength and modulus. The fiber which serves as a reinforcement in reinforced plastics may be synthetic or natural.
To this end, an investigation has been carried out to make use of coir, a natural fiber abundantly available in India. Natural
fibers are not only strong and lightweight but also relatively very cheap. The present work describes the development and
characterization of a new set of natural fiber based polymer composites consisting of coconut coir as reinforcement and epoxy
resin as matrix material. The developed composites are characterized with respect to their mechanical characteristics. Experiments
are carried out to study the effect of fiber length on mechanical behavior of these epoxy based polymer composites. Finally,
the scanning electron microscope (SEM) of fractured surfaces has been done to study their surface morphology. 相似文献
5.
In order to develop composites with better mechanical properties and environmental performance, it becomes necessary to increase
the hydrophobicity of the natural fibers and to improve the interface between matrix and natural fibers. Graft copolymerization
of natural fibers is one of the best methods to attain these improvements. Only few workers have reported the use of graft
copolymers as reinforcing material in the preparation of composites. So in the present paper, we report the preparation of
graft copolymers of flax fibers with methyl acrylate (MA) using Fenton’s reagent (FAS-H2O2) as redox system. Synthesized flax-g-poly(MA) was characterized with FTIR, TGA/DTA, scanning electron microscopy (SEM), and
X-ray diffraction (XRD) techniques. Composites were prepared using flax-g-poly(MA) as a reinforcement and phenolformaldehyde
(PF) as the binding material. Mechanical properties of phenol-formaldehyde composites were compared and it has been found
that composites reinforced with flax-g-poly(MA) showed improvement in mechanical properties. Composites reinforced with flax-g-poly(MA)
showed better tensile strength (235 N) and compressive strength (814 N) in comparison to composites reinforced with original
flax fiber which showed lesser tensile strength (162 N) and compressive strength (372 N). Composites reinforced with flax-g-poly(MA)
shows the improved MOR, MOE, and SP. 相似文献
6.
Fabrication of long and discontinuous natural fiber reinforced polypropylene biocomposites and their mechanical properties 总被引：1，自引：0，他引：1
Natural fiber reinforced polypropylene (PP) biocomposites were fabricated by blending long-and-discontinuous (LD) natural
fibers (NF) with LD PP fibers. Firstly, random fiber mats were prepared by mixing NFs and PP fibers using a carding process.
Then, heat and pressure were applied to the mats, such that the PP fibers dispersed in the mats melted and flowed out, resulting
in the formation of consolidated sheets upon subsequent cooling. The effect of the fiber volume fraction on the mechanical
properties of the bio-composites was scrutinized by carrying out tensile and flexural tests and observing the interface between
the fiber and matrix. It was observed that the natural LD fiber content needs to be maintained at less than the nominal fiber
fraction of 40 % by weight for the composites fabricated using the current method, which is quite low compared to that of
continuous or short fiber reinforced composites. The limited fiber fraction can be explained by the void content in the biocomposites,
which may be caused by the non-uniform packing or the deficiency of the matrix PP fibers. 相似文献
7.
Sayyed Mahdi Hejazi Mohammad Sheikhzadeh Sayyed Mahdi Abtahi Ali Zadhoush 《Fibers and Polymers》2013,14(2):277-284
The concept of reinforcing soil with natural fibers was originated in ancient times. However, short natural and synthetic fiber soil composites have recently attracted increasing attention in geotechnical engineering for the second time. Consequently in this work, shear behavior of fiber reinforced soil composite was modeled by using force-equilibrium method. The proposed model indicated that fiber percentage, fiber diameter, fiber aspect ratio, Elastic Modulus of fiber, coefficient of friction between fiber and matrix, the thickness of shearing zone and vertical compressive stress determine the shear resistance of a fiber reinforced soil composite. In the next step, a set of laboratory direct shear tests was performed on different samples including both neat soil and fiber reinforced treatments. In order to compare model outputs and experimental results, it was necessary to measure the coefficient of friction between fiber and soil. Therefore, a novel apparatus based on fiber pull-out test was designed to determine the interfacial shear stress between fiber and soil. Since, soil considers as a soft material and its mechanical properties depend on vertical stress, therefore, the Instron Tensile Tester was modified to provide fiber pull-out test through the soil matrix. Consequently, the proposed model adequately predicted shear behavior of fiber reinforced soil composite based on fiber pull-out test results. 相似文献
8.
A series of the long glass fiber reinforced thermoplastic polyurethane elastomers and poly (styrene-acrylonitrile) (LGF/TPU/SAN) composites with different contents of long glass fiber were prepared by using self-designed impregnation device. Dynamic mechanical properties of TPU/SAN matrix reinforced with 10, 20 and 30 % by weight long glass fibers have been investigated by using dynamic mechanical thermal analysis (DMA). The results indicated that the content of long glass fiber and scanning frequency had some influence on dynamic mechanical properties and glass transition of LGF/TPU/SAN composites. In addition, the Arrhenius relationship has been used to calculate the activation energy of a-transition of the LGF/TPU/SAN composites. SEM demonstrates the relatively good dispersion of the long glass fiber in the TPU/SAN matrix. In addition, Effects of the content of long glass fiber on mechanical properties of the LGF/TPU/SAN composites are investigated. 相似文献
9.
Bio-materials have ignited a quest among research fraternity to be used in every possible field of applications like automobile, sports, medical, civil and textile industry. Application spectrum of natural fiber reinforced polymer composites is spreading globally in every field of engineering having structural and tribological applications. The present work investigates the tribological performance of regionally available inexpensive plant based natural fiber reinforced polymer composites. In this work, three different types of natural fibers (jute, hemp, and flax) were reinforced with epoxy matrix to fabricate natural fiber reinforced polymer composites (NFRP) and their hybrid composites (jute/hemp/Epoxy, hemp/flax/epoxy and jute/ hemp/flax/epoxy) using hand-layup technique. Tribological performance of the developed bio-composites were evaluated in terms of frictional characteristics and sliding wear under dry contact condition at different process parameters, such as applied load (10-50 N), sliding speed (1-5 m/s) and sliding distance (1000-2000 m). Experimental results of wear analysis confirmed that incorporation of natural fibers into epoxy polymer matrix significantly improved the wear behavior of the developed NFRP composites in comparison to neat epoxy polymer. Among all the developed composites, jute/epoxy composite achieved the highest coefficient of friction, frictional force and specific wear rate. Dynamic mechanical analysis (DMA) was also analyzed to evaluate the viscoelastic behavior of the developed composites. The surface morphology of samples after wear test was examined by scanning electron microscopy to investigate and propose the possible wear mechanism of the developed composites. 相似文献
10.
Levi Gardner Troy Munro Ezekiel Villarreal Kurt Harris Thomas Fronk Heng Ban 《Fibers and Polymers》2018,19(2):393-402
Chemical treatment of natural fibers is a well-defined means of mechanical property improvement in natural fiberreinforced composites. An understanding of mechanical and thermal properties in these media is essential for evaluating heat transfer, thermal degradation, and overall performance of these composites over their product lifetime. However, very little information is available illustrating the effect of such treatment on the thermal properties of kenaf composites. Also, no study to date has reported the thermal conductivity of individual kenaf fibers. This study reports the effects of fiber treatment (in 6 % NaOH) on thermal transport in unidirectionally oriented kenaf-epoxy composites and individual kenaf fibers. The effective thermal conductivities and thermal diffusivities of chemically treated fiber composites show a general increase over untreated fiber composites (0.210 to 0.232 W/m/K at 28 °C, 0.206 to 0.234 W/m/K at 200 °C). This improvement may be attributed to improved interfacial contact between the fibers and epoxy matrix shown in microstructural images after chemical treatment. The thermal conductivity of individual fibers was evaluated at room temperature using two techniques. Results from both techniques showed slight increases after chemical treatment (0.58±0.53 to 1.0±0.13 W/m/K and 1.2±0.54 to 1.6±0.28 W/m/K) but lacked statistical significance. Any improvement in surface crystallinity after chemical treatment does not appear to affect overall fiber thermal conductivity. A better understanding of thermal transport in kenaf fibers and composites enables better estimation of the performance of these composites in different applications. Moreover, the thermal conductivities of individual fibers are useful in understanding the fiber’s contribution to conduction in different fiber reinforcement configurations. 相似文献
11.
Quazi T. H. Shubhra A. K. M. M. Alam M. A. Gafur Sayed M. Shamsuddin Mubarak A. Khan M. Saha Dipti Saha M. A. Quaiyyum Jahangir A. Khan Md. Ashaduzzaman 《Fibers and Polymers》2010,11(5):725-731
Natural fibers are largely divided into two categories depending on their origin: plant based and animal based. Plant based
natural jute fiber reinforced polypropylene (PP) matrix composites (20 wt% fiber) were fabricated by compression molding.
Bending strength (BS), bending modulus (BM), tensile strength (TS), Young’s modulus (YM), and impact strength (IS) of the
composites were found 44.2 MPa, 2200 MPa, 41.3 MPa, 750 MPa and 12 kJ/m2, respectively. Animal based natural B. mori silk fiber reinforced polypropylene (PP) matrix composites (20 wt% fiber) were fabricated in the same way and the mechanical
properties were compared over the silk based composites. TS, YM, BS, BM, IS of silk fiber reinforced polypropylene composites
were found 55.6 MPa, 760 MPa, 57.1 MPa, 3320 MPa and 17 kJ/m2 respectively. Degradation of composites in soil was measured upto twelve weeks. It was found that plant based jute fiber/PP
composite losses its strength more than animal based silk fiber/PP composite for the same period of time. The comparative
study makes it clear that mechanical properties of silk/PP composites are greater than those values of jute/PP composites.
But jute/PP composites are more degradable than silk/PP composites i.e., silk/PP composites retain their strength for a longer
period than jute/PP composites. 相似文献
12.
This study has examined the flexural properties of natural and chemically modified coir fiber reinforced cementitious composites
(CFRCC). Coir fibers of two different average lengths were used, and the longer coir fibers were also treated with a 1 % NaOH
solution for comparison. The fibers were combined with cementitious materials and chemical agents (dispersant, defoamer or
wetting agent) to form CFRCC. The flexural properties of the composites, including elastic stress, flexural strength, toughness
and toughness index, were measured. The effects of fiber treatments, addition of chemical agents and accelerated ageing of
composites on the composites’ flexural properties were examined. The results showed that the CFRCC samples were 5–12 % lighter
than the conventional mortar, and that the addition of coir fibers improved the flexural strength of the CFRCC materials.
Toughness and toughness index, which were associated with the work of fracture, were increased more than ten times. For the
alkalized long coir fiber composites, a higher immediate and long-term toughness index was achieved. SEM microstructure images
revealed improved physicochemical bonding in the treated CFRCC. 相似文献
13.
Most materials used in daily life are polymeric materials based on petrochemistry. The used polymeric materials can cause land pollution and air pollution after landfill or incineration. In contrast, natural fiber reinforced (NFR) composites are more suitable for the environment, however the reliability in terms of the durability and weatherability of NFR composites is still lacking. Thus, NFR composites require the reliability involved with durability and weatherability. In this work, poly(butylene terephthalate-co-glutarate) (PBTG), with a chemical structure similar to biodegradable PBAT, was used as the matrix in the composites, and hemp fibers were used as the reinforcement. Hemp/PBTG composites were fabricated by stacking hemp-fiberwebs and PBTG films with various fiber contents and thermal exposure times. Characteristics of the composites, such as the morphological structure, chemical structure, tensile properties, compressive properties, flexural properties, and impact strength, were analyzed to obtain the effects of fiber volume fraction and thermal exposure. As a result, hemp/PBTG composites were hardened in proportion to fiber volume fractions, and the hardening behavior of the composites increased tensile strength and flexural strength. However, the hardened structure of the composites decreased the impact strength and compressive strength of the composites. On the other hand, the mechanical properties of hemp/PBTG composites with thermal exposure times, were governed significantly by the brittleness behavior of the resin and the increased crystallinity of hemp fibers. Thus, the hemp fibers contributed to the improvements on structural stability, tensile strength and flexural strength of the hemp/PBTG composites, and increased the thermal durability of the composites with various thermal exposures. 相似文献
14.
《Industrial Crops and Products》2006,23(1):1-8
Plant fiber reinforced thermoplastic composites have gained much attraction in structural applications such as building and automotive products. Agricultural residues such as wheat straw, bagasse, and corn stover can also be exploited as readily available natural fiber resources for similar applications. The objective of this study was to extract fibers from wheat straw and also to determine the usefulness of fungal retting of wheat straw before extracting the fibers. Wheat straw was mechanically defibrillated using a laboratory-scale mechanical refiner before and after fungal retting. Fiber characteristics such as physico-chemical and mechanical properties, surface characteristics, and thermal properties of the resultant fibers were measured in order to explore the possibilities of using the fibers as reinforcing materials. Retted fibers were stronger than un-retted fibers. The length and diameter of the retted fibers were lower than the un-retted fibers. FT-IR spectroscopic analysis of the wheat straw fibers indicated the fractional removal of hemicelluloses and lignin from the retted fiber. X-ray photoelectron spectroscopy (XPS) of the fibers showed the partial removal of extractives from the surface of the retted fibers. Also, the oxygen to carbon ratio (O/C) of the fibers illustrated that there is more lignin type surface structure for both retted and un-retted fibers. However, slightly higher ratio of oxygen to carbon in the retted fiber indicated a more carbohydrate-rich fiber than the un-retted fiber. Thermal degradation characteristics demonstrated the suitability of processing wheat straw fibers with thermoplastics. 相似文献
15.
Narendra ReddyYiqi Yang 《Industrial Crops and Products》2011,33(1):35-41
Soyprotein-jute fiber composites developed using water without any chemicals as the plasticizer show much better flexural and tensile properties than polypropylene-jute composites. Co-products of soybean processing such as soy oil, soyprotein concentrate and soy protein isolates are inexpensive, abundantly available and are renewable resources that have been extensively studied as potential matrix materials to develop biodegradable composites. However, previous attempts on developing soy-based composites have either chemically modified the co-products or used plasticizers such as glycerol. Chemical modifications make the composites expensive and less environmentally friendly and plasticizers decrease the properties of the composites. In this research, soyprotein composites reinforced with jute fibers have been developed using water without any chemicals as plasticizer. The effects of water on the thermal behavior of soyproteins and composite fabrication conditions on the flexural, tensile and acoustic properties of the composites have been studied. Soyprotein composites developed in this research have excellent flexural strength, tensile strength and tensile modulus, much higher than polypropylene (PP)-jute fiber composites. The soyprotein composites have better properties than the PP composites even at high relative humidity (90%). 相似文献
16.
The chemical and morphological properties of ramie fibers treated by chemical surface modification were examined with Fourier
transform infrared (FT-IR) spectroscopy. The mechanical and thermal decomposition properties were evaluated with respect to
tensile strength, tensile modulus and thermogravimetric analysis (TGA). Surface morphological changes were investigated with
scanning electron microscopy (SEM). Finally, the capabilities of composites reinforced with various chemically treated fibers
were analyzed by investigating tensile and impact strengths. Additionally, the thermal mechanical properties of the composites
were investigated with thermal mechanical analysis (TMA). Based on the results of these analyses, we concluded that pectin,
lignin and hemicellulose were removed and thermal stability was increased with chemical treatments. The composites reinforced
with ramie fiber showed better properties compared with pure PLA matrix with respect to tensile and impact strengths. The
peroxide-treated fiber composite had the smallest thermal expansion. 相似文献
17.
Ni-coated short carbon fibers (Ni-SCFs) were prepared using an electrodeposition method. Short carbon fiber (SCF) reinforced epoxy composites were prepared by changing the fiber content (0.1–0.7 wt%). To investigate the effect of Ni-coated short carbon fibers on the mechanical and electrical properties of the composites, we prepared two kinds of reinforcements: the short carbon fibers treated by 400 °C (400 °C treated SCFs) and Ni-SCFs. Fracture characteristics of the composites revealed the Ni coatings and the epoxy matrix had a better interface, so that the results of tensile and bending strength were better in epoxy/Ni-SCFs composites than those in epoxy/400 °C treated SCFs composites. The 400 °C treated SCFs decreased the electrical resistivity of the epoxy composites, compared to the pure epoxy. However the epoxy/Ni-SCFs composites had lower electrical resistivity than epoxy/400 °C treated SCFs with the same fiber content. 相似文献
18.
M. A. Abd El-baky 《Fibers and Polymers》2017,18(12):2417-2432
A study on the tensile and flexural properties of jute-glass-carbon fibers reinforced epoxy hybrid composites in inter-ply configuration is presented in this paper. Test specimens were manufactured by hand lay-up process and their tensile and flexural properties were obtained. The effects of the hybridization, different fibers content and plies stacking sequence on the mechanical properties of the tested hybrid composites were investigated. Two-parameter Weibull distribution function was used to statistically analyze the experimental results. The failure probability graphs for the tested composites were drawn. These graphs are important tools for helping the designers to understand and choose the suitable material for the required design and development. Results showed that the hybridization process can potentially improve the tensile and flexural properties of jute reinforced composite. The flexural strength decreases when partial laminas from a carbon/epoxy laminate are replaced by glass/epoxy or jute/epoxy laminas. Also, it is realized that incorporating high strength fibers to the outer layers of the composite leads to higher flexural resistance, whilst the order of the layers doesn’t affect the tensile properties. 相似文献
19.
Maize stalk has become one of the major sources of fibers from the agricultural residues. Use of these fibers as a reinforcement in the polymer is described in this paper. The present work is focused on establishing the properties such as physical, chemical, morphological structure and thermal properties of maize stalk fiber using different characterization techniques. Simple hand layup method was followed for processing the composite material. Chemical treatments of fibers were carried out to study the interaction of fibers with the matrix. The results revealed that maize fibers can also be used as a traditional fiber as reinforcement in a natural fiber reinforced composite materials. 相似文献
20.
In the present paper, ramie fiber reinforced polymer (RFRP) plates prepared by hot compression process were subjected to water immersion at 20 oC and 40 oC for four weeks, and the variation of water uptake and mechanical properties with immersion time were investigated. It was found that the saturated water content and the coefficient of diffusion in RFRP were much higher than those in synthetic fiber based composites, due to the strong hydrophilic characteristic of the ramie fiber. After fully drying of the immersed samples, mass loss from 1.6 % to 3.6 % was found, indicating occurrence of a serious hydrolysis of the resin and the ramie fibers. After a short term of immersion (i.e., 1 day), RFRP showed a remarkable deterioration in the flexural and short beam shear properties. Further increase of the immersion time, the degradation rate of the mechanical properties was much reduced. After fully drying, the mechanical properties of the samples can be recovered to some extent, but still much less than the original values. The variation of mechanical property as a function of the water uptake content exhibits three stages (i.e., dramatic reduction, leveling off and quick decrease again). This may be due to the sequent occurrence of the degradation of natural fibers, fiber debonding and hydrolysis of the fiber and resin during immersion. 相似文献