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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.
In this study, PLA/PC blends were prepared in order to investigate the effects of the addition of PC loading level into PLA matrix on the mechanical properties of these blends. After that, PLA/PC (70/30), which has the lowest tensile strength value, was selected as a control sample for the compatibilization study. Commercial styrene-acrylic multi-functional-epoxide oligomeric agent (SAmfE), styrene maleic anhydride copolymer (SMA), tetrasilanol phenyl polyhedral oligomeric silsesquioxane (T-POSS) and glycidyl isooctyl-polyhedral oligomeric silsesquioxane (G-POSS) were used as compatibilizers for PLA/PC blends. The variation of mechanical, thermal, structural and morphological properties were examined by conducting tensile tests, dynamic mechanical analyses, differential scanning calorimetry, Fourier Transform IR and scanning electron microscope analyses. Tensile test results showed that the tensile strength and elongation at break values of the PLA/PC blend compatibilized with SAmfE were higher than those of the other blends. DSC analyses revealed that Tg and Tm values of the blends were not significantly affected by compatibilizer but, degree of crystallinity was found to be sensitive to compatibilizer type. DMA results showed that the best mechanical properties were obtained for the PLA/PC/SAmfE blend. When all of the results evaluated, it was found that the SAmfE is the most effective compatibilizer among the using compatibilizer types for PLA/PC blends.  相似文献   

3.
Cassava bagasse is an inexpensive and broadly available waste byproduct from cassava starch production. It contains roughly 50% cassava starch along with mostly fiber and could be a valuable feedstock for various bioproducts. Cassava bagasse and cassava starch were used in this study to make fiber-reinforced thermoplastic starch (TPSB and TPSI, respectively). In addition, blends of poly (lactic acid) and TPSI (20%) and TPSB (5, 10, 15, 20%) were prepared as a means of producing low cost composite materials with good performance. The TPS and PLA blends were prepared by extrusion and their morphological, mechanical, spectral, and thermal properties were evaluated. The results showed the feasibility of obtaining thermoplastic starches from cassava bagasse. The presence of fiber in the bagasse acted as reinforcement in the TPS matrix and increased the maximum tensile strength (0.60 MPa) and the tensile modulus (41.6 MPa) compared to cassava starch TPS (0.40 and 2.04 MPa, respectively). As expected, blending TPS with PLA reduced the tensile strength (55.4 MPa) and modulus (2.4 GPa) of neat PLA. At higher TPSB content (20%) the maximum strength (19.9 MPa) and tensile modulus (1.7 GPa) were reduced about 64% and 32%, respectively, compared to the PLA matrix. In comparison, the tensile strength (16.7) and modulus (1.2 GPa) of PLA blends made with TPSI were reduced 70% and 51% respectively. The fiber from the cassava bagasse was considered a filler since no increase in tensile strength of PLA/TPS blends was observed. The TPSI (33.1%) had higher elongation to break compared to both TPSB (4.9%) and PLA (2.6%). The elongation to break increased from 2.6% to 14.5% by blending TPSI with PLA. In contrast, elongation to break decreased slightly by blending TPSB with PLA. Thermal analysis indicated there was some low level of interaction between PLA and TPS. In PLA/TPSB blends, the TPSB increased the crystallinity of the PLA component compared to neat PLA. The fiber component of TPSB appeared to have a nucleating effect favoring PLA crystallization.  相似文献   

4.
Fully biodegradable and environment-friendly green composite specimens were made using ramie fibers and soy protein concentrate (SPC) resin. SPC was used as continuous phase resin in green composites. The SPC resin was plasticized with glycerin. Precuring and curing processes for the resin were optimized to obtain required mechanical properties. Unidirectional green composites were prepared by combining 65 % (on weight basis) ramie fibers and SPC resin. The tensile strength and Young’s modulus of these composites were significantly higher compared to those of pure SPC resin. Tensile and flexural properties of the composite in the longitudinal direction were moderate and found to be significantly higher than those of three common wood varieties. In the transverse direction, however, their properties were comparable with those of wood specimens. Scanning electron microscope (SEM) micrographs of the tensile fracture surfaces of the green composite indicated good interfacial bonding between ramie fibers and SPC resin. Theoretical values for tensile strength and Young’s modulus, calculated using simple rule of mixture were higher than the experimentally obtained values. The main reasons for this discrepancy are loss of fiber alignment, voids and fiber compression due to resin shrinking during curing.  相似文献   

5.
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   

6.
In this study, physical, mechanical, and flammability properties of coconut fiber reinforced polypropylene (PP) composite panels were evaluated. Four levels of the coir fiber content (40, 50, 60, and 70 % based on the composition by weight) were mixed with the PP powder and a coupling agent, 3 wt % maleic anhydride grafted PP (MAPP) powder. The water resistance and the internal bond strength of the composites were negatively influenced by increasing coir fiber content. However, the flexural strength, the tensile strength, and the hardness of the composites improved with increasing the coir fiber content up to 60 wt %. The flame retardancy of the composites improved with increasing coir fiber content. The results suggest that an optimal composite panel formulation for automotive interior applications is a mixture of 60 wt % coir fiber, 37 wt % PP powder, and 3 wt % MAPP.  相似文献   

7.
Denim, a twilled cotton fabric, was used to enhance the mechanical and thermal properties of poly(lactic acid) (PLA). The denim fabric reinforced composites with different numbers of denim layers were fabricated by using a hand layup method. The impact, tensile, and dynamic mechanical properties of the composites were observed with increasing denim layers to examine the reinforcing effect of denim fabrics. Numerical analysis was carried out to model the elastic modulus of the composite by using a commercial software. Three-dimensional geometry of the denim fabric reinforced PLA composite was generated through a CAD program, and the elastic modulus was calculated by applying uniform deformation on one surface. The impact strength, tensile strength, and thermal properties of the composites were improved by piling denim fabrics. The denim fabric reinforced composites exhibited outstanding impact strength due to the retarded crack propagation as well as large energy dissipation. The 3 layer denim reinforced composite showed best results among all specimens, and its impact strength, tensile strength, and tensile modulus were measured to be 82 J/m, 75.76 MPa, and 4.65 GPa, respectively. The PLA/denim composites have good mechanical properties and can substitute traditional composites such as glass fiber or carbon fiber reinforced composites.  相似文献   

8.
Present research investigates the mechanical properties of jute-coir fiber reinforced hybrid polypropylene (PP) composite with fiber loading variation and observes the effect of chemical treatment of fiber on property enhancement of the composites. Composites were manufactured using hot press machine at four levels of fiber loading (5, 10, 15 and 20 wt%). Fiber ratio’s were varied (jute:coir=1:1, 3:1 and 1:3) for 20 % fiber loaded composites. Both jute and coir fiber was treated using 5 % and 10 % NaOH solutions. Composites were also prepared using treated fiber with jute-coir fiber ratio of 3:1. Tensile, flexural, impact and hardness tests and Fourier transform infrared spectroscopic analysis were conducted for characterization of the composites. Tensile test of composite showed a decreasing trend of tensile strength and increasing trend of the Young’s modulus with increase in fiber loading. During flexural, impact and hardness tests, the flexural strength, flexural modulus, impact strength and hardness values were found to be increased with increase in fiber loading. All these properties enhanced with the enhancement of jute content except impact strength. 5 % NaOH treatment provided an improving trend of properties whereas, 10 % NaOH treatment showed the reverse one. The FTIR analysis of the composites indicated decrease of hemicelluloses and lignin content with alkali treatment.  相似文献   

9.
The work focuses on the influencing effect of fiber surface treatment by BP towards mechanical properties of BSF reinforced PLA composites. BSF were treated by BP to improve the adhesion between fibres and matrix. BSF (30 wt %) reinforced PLA (70 wt %) hybrid composites were fabricated by means of twin screw extrusion followed by injection molding process. Tensile strength, flexural strength and modulus were tested by means of UTM. The morphological analysis of the untreated and treated BSF reinforced PLA composites in comparison with virgin PLA was carried out by SEM to examine the existence of interfacial adhesion between BSF and PLA. The resultant data reveals that treated BSF restricts the motion of the PLA matrix due to better wettability and bonding. Consequently, mechanical properties like tensile and flexural moduli of BSF reinforced PLA composites were enhanced in comparison to virgin PLA and untreated BSF reinforced PLA composites. The results are discussed in detail.  相似文献   

10.
In the present study, nanofibrils of cellulose are extracted from waste jute fibers using high energy planetary ball milling process in wet condition. The rate of refinement of untreated fibers having non-cellulosic contents was found slower than treated fibers due to strong holding of fiber bundles by non-cellulosic contents. At the end of three hours of wet milling, untreated fibers were refined to the size of 850 nm and treated fibers were refined to the size of 443 nm. In the subsequent stage, composite films of poly lactic acid (PLA) were prepared by solvent casting with 3 wt% loading of untreated jute nanofibrils, treated jute nanofibrils and microcrystalline cellulose. The influence of non-cellulosic contents on mechanical properties of PLA films are investigated based on results of tensile test, dynamic mechanical analysis and differential scanning calorimetry. The maximum improvement was observed in case of treated jute nanofibril/PLA composite film where initial modulus and tensile strength increased by 207.69 % and 168.67 %, respectively as compared to neat PLA film. These improvements are attributed to the increased interaction of treated jute nanofibrils with PLA matrix due to their higher precentage of cellulosic contents and mechanically activated surface.  相似文献   

11.
In this work, the effect of organosolv lignin on properties of polypropylene (PP)/chitosan composites was investigated. Mechanical and thermal properties of the composites were analyzed by means of ASTM D 638-91, ASTM D 256, thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). Tensile strength and elongation at break of the PP composites decreased upon the presence of chitosan filler, but Young’s modulus improved. Impact strength was found to increase with the maximum value at 30 php of filler loading. At a similar loading, treated PP/chitosan composites were found to have higher tensile strength, elongation at break, Young’s modulus as well as impact strength than untreated composites. Furthermore, the presence of organosolv lignin imparted a plasticizing effect. Thermal properties of the treated PP/chitosan composites were better as compared with the untreated PP/chitosan composites; although the chemical treatment did not alter the thermal degradation mechanism. In addition, the obtained results were comparable to results from previous studies. This finding implied that the organosolv lignin could be a potential reagent to replace its synthetic counterpart.  相似文献   

12.
This work investigated the effects of date palm leaf fiber (DPLF) content on the thermal and tensile properties; and morphology of compatibilized polyolefin ternary blend. Recycled polyolefin ternary blend consisting of low density polyethylene (RLDPE), high density polyethylene (RHDPE) and polypropylene (RPP) were fabricated at different parts per hundred resin (phr) of DPLF. Maleic anhydride grafted polyethylene (MAPE) was used as compatibilizer to enhance the adhesion between filler and polymer matrix. The composites were prepared using melt extrusion and tests samples were produced via injection molding process. Thermal conductivity results showed that as much as 11 % reduction in thermal conductivity was achieved with the incorporation of 30 phr DPLF. Highest tensile strength was observed with the incorporation of 10 phr DPLF. The elongation at break was reduced with the addition of DPLF due to impediment of chain mobility by the fillers. Initial degradation temperature increased with the addition of DPLF. Hence, it is concluded that DPLF can be used to develop green and thermally insulating composites. It is hoped that the present results will stimulate further studies on the thermally insulative materials based on natural fibers reinforced polymer composites for applications in the building industries.  相似文献   

13.
In order to explore an alternative method instead of plasticization for improving the toughness, flexibility and processability of PLA based packaging films, two different kinds of modified polyethylene based elastomers, such as glycidyl methacrylate or maleic anhydride functionalized ethylene-acrylate based elastomers, were melt blended with PLA. Their properties were compared with conventional PEG plasticized PLA. The chemical interaction between end groups of PLA and epoxide or maleic anhydride functional groups of elastomers was shown by FTIR. Scanning electron microscopy showed that up to 20 % PEG loading, one phase morphology was achieved, however beyond this point, a phase separation was observed for plasticized PLA. For PLA/elastomer blends, a two-phase morphology was obtained as a result of immiscible nature of PLA and elastomers. Tensile and dynamic mechanical properties indicated that elastomer based blends were better than plasticized PLA independently from elastomer type. Differential scanning calorimeter (DSC) analysis exhibited that the T g value was remarkably lowered in the plasticized PLA; however, it did not change in the case of elastomers. In terms of oxygen permeability and biodegradability, plasticized PLA was found to be better than elastomer based blends.  相似文献   

14.
Polymeric composites based on cotton burr and cottonseed bull have been prepared by melt blending and extrusion. For poly(lactic acid) (PLA) and low-density polyethylene (LDPE), addition of the fillers slightly changed the composite's thermal properties but significantly decreased the composite's mechanical properties. Heat treatment prior to extrusion resulted in composites with better tensile strength and Young's modulus. The use of maleic anhydride and peroxide only slightly improved the physical properties of the LDPE materials, but the effect was less clear for the PLA materials. The PLA-filler composites may be useful for lowering the cost of the materials in applications that can tolerate the decreased properties. In addition, the addition of fillers to LDPE might be beneficial in applications to improve stiffness or to improve biodegradability.  相似文献   

15.
Chemical treatment is an often-followed route to improve the physical and mechanical properties of natural fiber reinforced polymer matrix composites. In this study, the effect of chemical treatment on physical and mechanical properties of jute fiber reinforced polypropylene (PP) biocomposites with different fiber loading (5, 10, 15, and 20 wt%) were investigated. Before being manufactured jute fiber/PP composite, raw jute fiber was chemically treated with succinic anhydride for the chemical reaction with cellulose hydroxyl group of fiber and to increase adhesion and compatibility to the polymer matrix. Jute fiber/PP composites were fabricated using high voltage hot compression technique. Fourier Transform Infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) tests were employed to evaluate the morphological properties of composite. Succinic anhydride underwent a chemical reaction with raw jute fiber which was confirmed through FTIR results. SEM micrographs of the fractured surface area were taken to study the fiber/matrix interface adhesion and compatibility. Reduced fiber agglomeration and improved interfacial bonding was observed under SEM in the case of treated jute fiber/PP composites. The mechanical properties of jute/PP composite in terms of Tensile strength and Young’s modulus was found to be increased with fiber loading up to 15 wt% and decreased at 20 wt%. Conversely, flexural strength and flexural modulus increased with fiber loading up to 10 wt% and start decreasing at 15 wt%. The treated jute/PP composite samples had higher hardness (Rockwell) and lower water absorption value compared to that of the untreated ones.  相似文献   

16.
Although the pineapple leaf fibers (PALF) are long known as domestic threading material in Malaysia, they are currently of little use despite being mechanically and environmentally sound. This study evaluated some selected properties of Josapine PALF and PALF-vinyl ester composites as well as the effects of simple abrasive combing and pretreatments on fiber and composite properties. Using PALF vascular bundles extracted from different parts of the leaves did not significantly affect PALF-vinyl ester composite mechanical properties. At low weight fraction and consolidating pressure, PALF fibers regardless of diameters and locations performed equally well in enhancing composite flexural properties under static loading. Finer bundles enhanced PALF-vinyl ester composite toughness indicated by tests at higher speeds. Abrasive combing produces cleaner and finer bundles suitable for reinforcing composites for applications not requiring high toughness.  相似文献   

17.
1-Ally-3-methylimidazolium chloride ([AMIM]Cl) was successfully synthesized and was used as a green spinning solvent for cellulose. The celluloses of various degrees of polymerization (DP) were dissolved in the [AMIM]Cl to obtain 5 % (w/w) cellulose solutions, which were regenerated to cellulose fibers through wet spinning process. Of three different regenerated cellulose fibers with different DPs, a DP of 2,730 was gave the strongest regenerated fiber without drawing having a tensile strength of 177 MPa and an elongation at break of 9.6 % respectively, indicating that celluloses of higher molecular weight can be entangled and oriented more easily. Also maximum draw ratio of the as-spun fibers increased from 1.2 to 1.7 with increasing degree of polymerization leading to a tensile strength and modulus of 207 MPa and 48 GPa, respectively. Particularly the tensile modulus was substantially higher than those of lyocell and high performance viscose fibers of 20 GPa or less. The higher DP of pristine cellulose was critical in increasing the mechanical properties such as tensile strength and elongation at break of the as-spun fibers coupled with higher tensile modulus after drawing.  相似文献   

18.
In this study, we report the fabrication and evaluation of a hybrid multi-scale basalt fiber/epoxy composite laminate reinforced with layers of electrospun carbon nanotube/polyurethane (CNT/PU) nanofibers. Electrospun polyurethane mats containing 1, 3 and 5 wt% carbon nanotubes (CNTs) were interleaved between layers of basalt fibers laminated with epoxy through vacuum-assisted resin transfer molding (VARTM) process. The strength and stiffness of composites for each configuration were tested by tensile and flexural tests, and SEM analysis was conducted to observe the morphology of the composites. The results showed increase in tensile strength (4–13 %) and tensile modulus (6–20 %), and also increase in flexural strength (6.5–17.3 %) and stiffness of the hybrid composites with the increase of CNT content in PU nanofibers. The use of surfactant to disperse CNTs in the electrospun PU reinforcement resulted to the highest increase in both tensile and flexural properties, which is attributed to the homogeneous dispersion of CNTs in the PU nanofibers and the high surface area of the nanofibers themselves. Here, the use of multi-scale reinforcement fillers with good and homogeneous dispersion for epoxy-based laminates showed increased mechanical performance of the hybrid composite laminates.  相似文献   

19.
In this work, hybrid composites were fabricated by hand layup method to hybridize treated Pineapple leaf fibre (PALF) and kenaf fibre (KF) in order to achieve superior mechanical properties on untreated hybrid composites. Silane treated PALF/KF phenolic hybrid composites were prepared on various fibre fraction to investigate mechanical properties and compared with untreated PALF/KF phenolic hybrid composites. The effects of silane treatment on hybrid composites were investigated by fourier transform infrared spectroscopy (FTIR) and found very effective peaks. Effects of treated hybrid composites were morphologically investigated by using scanning electron microscopy images and analysed the tensile results. Treated PALF/KF phenolic hybrid composites enhanced the flexural strength, modulus, impact strength and energy absorption while tensile strength and modulus decreased. The overall performances of 70 % PALF 30 % Kenaf hybrid composites were improved after silane treatment. Silane treatment of fibres improved the mechanical performance of hybrid composites and it can be utilized to produce components for building structure, materials and automobile applications.  相似文献   

20.
Composites were prepared with 13, 23 30 and 40 % fiber and evaluated the mechanical performance in tensile, flexural and impact. The mechanical properties of these composites were also evaluated function of time at 110 °C thermal exposure. Caroa fibers were characterized by techniques such as thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the best mechanical properties were achieved for composites containing 23 to 30 % fiber. The incorporation of 23 % fiber caroa increased both the modulus of elasticity in the tensile test as the flexural strength and impact, the composite with 30 % fiber caroa showed higher tensile strength. The results show that the tensile and flexural strength of the composite decreased with time of thermal exposure. The thermal aging at 110 °C caused a decrease in tensile properties of the composites.  相似文献   

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