Yuanxin Zhou - Academia.edu (original) (raw)

Papers by Yuanxin Zhou

Materials Science and Engineering: A, 2005

Tensile experiments conducted on an injection molded short E-glass fiber reinforced polyamide-6,6... more Tensile experiments conducted on an injection molded short E-glass fiber reinforced polyamide-6,6 composite show that flow-induced fiber orientation due to injection molding caused higher tensile properties in the direction of flow compared to normal to the direction of flow. The presence of weld line reduced the modulus, tensile strength and failure strain of the material. Both elastic modulus and tensile strength of the material increased with increasing strain rate, indicating that this composite was a strain rate dependent material. Based on the experimental results, a nonlinear damage model was established to describe the stress-strain relationship of the short fiber reinforced polyamide-6,6. The parameters in this model are tensile modulus E, Weibull scale parameter σ 0 and Weibull shape parameter β. It is shown that the Weibull shape parameter, β, does not depend on strain rate, and can be regarded a constant; however, the Weibull scale parameter, σ 0 , is a linear function of log (strain rate).

Journal of Materials Science

Tensile mechanical behavior of T300 fiber bundles and M40J fiber bundles have been studied in the... more Tensile mechanical behavior of T300 fiber bundles and M40J fiber bundles have been studied in the strain rate range from 0.001 1/s to 1300 1/s and complete stress strain curves were obtained. Results show that both ultimate strength and failure strain of two materials are strain rate insensitive, and T300 fiber and M40J fiber can be regarded as strain rate insensitive materials. On basis of the fiber bundles model and the statistic theory of fiber strength, single Weibull distribution model and bimodal Weibull distribution model have been developed to describe mechanical behavior of fiber bundles. And a method for determine the statistic parameters of fibers by tensile tests of fiber bundles is established, too. The simulated stress strain curves from the model are in good agreement with the test data. Simulated results show that the strength of T300 fiber can be described by single Weibull distribution function, and the strength of M40J fiber should be described by bimodal Weibull ...

Materials Science and Engineering: A, 2008

In the present paper, vapor-grown carbon nanofibers were mechanically dry-mixed with polypropylen... more In the present paper, vapor-grown carbon nanofibers were mechanically dry-mixed with polypropylene powder and extruded into filaments with a single screw extruder. Then tensile tests were performed on the single filament at a strain rate range from 0.02min−1 to 2min−1. Results indicate that both neat and nanophased polypropylene were strain rate-strengthening material. The tensile modulus and yield strength both increased

Volume 13: Processing and Engineering Applications of Novel Materials, 2007

In this study, electrical, thermal and mechanical properties of multi-walled carbon nanotubes (CN... more In this study, electrical, thermal and mechanical properties of multi-walled carbon nanotubes (CNTs) reinforced Epon 862 epoxy have been evaluated. Firstly, 0.1 wt%, 0.2 wt%, 0.3 wt%, and 0.4 wt% CNT were infused into epoxy through a high intensity ultrasonic liquid processor and then mixed with EpiCure curing agent W using a high speed mechanical agitator. The trapped air and reaction volatiles were removed from the mixture using a high vacuum. Neat epoxy sample also was made as reference. Electrical conductivity, dynamic mechanical analysis (DMA, three point bending tests and fracture tests were performed on unfilled, CNT-filled epoxy to identify the loading effect on the properties of composites. Experimental results show significant improvement in electric conductivity. The resistivity of epoxy decreased to 15Ωm with 0.4% CNT. DMA studies revealed that filling the carbon nanotube into epoxy can produce a 90% enhancement in storage modulus and a 17° C increase in Tg, but CNT has ...

Applied Mechanics, 2005

In this paper, loading and loading-unloading tests of carbon fiber reinforced aluminum laminates ... more In this paper, loading and loading-unloading tests of carbon fiber reinforced aluminum laminates (CRALL) have been carried out in a tensile impact apparatus, and quasi-static tensile tests have been performed on a MTS-810 machine. Complete stress-strain curves of composite in the strain rate range from 0.001–1200 1/s have been obtained. Experimental results show that CRALL composite is a strain rate sensitivity material, the tensile strength and failure strain both increased with increasing strain rate. A linear strain hardening model has been combined with Weibull distribution function to establish a constitutive equation for CRALL. The simulated stress-strain curves from model are in good agreement with the test data. The analysis of the model shows that the Weibull scale parameter, σ0, increased with increasing strain rate, but Weibull shape parameter, β, can be regarded as a constant.

International Journal of Nanoscience, 2008

A novel sonochemical method is developed to coat multi-walled carbon nanotubes (MWCNTs) on expand... more A novel sonochemical method is developed to coat multi-walled carbon nanotubes (MWCNTs) on expandable thermoplastic (acrylonitrile and methylacrylonitrile polymer) microspheres (Expancel). These polymeric thermoplastic microspheres were further fabricated in a form of foam panels using a compression molding technique. The test coupons were cut precisely from the as-prepared panels and characterized by scanning electron microscopy (SEM), X-ray diffraction, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The SEM studies have shown that the MWCNTs are well dispersed over the entire volume of the matrix with minimal agglomeration. The foam cell structures are well-ordered, spherical in shape, and uniform in size. The TGA and DSC analyses indicate that the nanocomposite foam samples are thermally more stable than the corresponding neat foam samples. The compression tests have been carried out for both nanocomposite and neat foam samples. These test results s...

Materials, Nondestructive Evaluation, and Pressure Vessels and Piping, 2006

In the present study, effect of vapor grown carbon nanofiber on the mechanical and thermal proper... more In the present study, effect of vapor grown carbon nanofiber on the mechanical and thermal properties of polypropylene was investigated. Firstly, nanofibers were dry-mixed with polypropylene powder and extruded into filaments by using a single screw extruder. Then the tensile tests were performed on the single filament at the strain rate range from 0.02/min to 2/min. Experiments results show that both neat and nano-phased polypropylene were strain rate strengthening material. The tensile modulus and yield strength both increased with increasing strain rate. Experimental results also show that infusing nanofiber into polypropylene can increase tensile modulus and yield strength, but decrease the failure strain. At the same time, thermal properties of neat and nano-phased polypropylene were characterized by TGA. TGA results have showed that the nanophased system is more thermally stable. At last, a nonlinear constitutive equation has been developed to describe strain rate sensitive behavior of neat and nano-phased polypropylene.© 2006 ASME

Volume 8: Mechanics of Solids, Structures and Fluids; Vibration, Acoustics and Wave Propagation, 2011

In this study, the nanophased epoxy with 2 wt.% clay was utilized in a vacuum assisted resin tran... more In this study, the nanophased epoxy with 2 wt.% clay was utilized in a vacuum assisted resin transfer molding (VARTM) set up with carbon fabric to fabricate laminated composites. The effectiveness of clay addition on mechanical properties of composites has been evaluated by tensile, flexural and fatigue test. The tensile and flexural strengths improved by 5.7% and 13.5%, respectively as compared to the neat composite. The fatigue strength was also improved significantly. Based on the experimental result, a linear damage model combined with the Weibull distribution function has been established to describe static failure processing of neat and nanophased carbon/epoxy. The simulated stress strain curves from the model are in good agreement with the test data. Simulated results show that damage processing of neat and nanophased carbon/epoxy described by bimodal Weibull distribution function.

Materials Science and Engineering: A, 2005

In the present paper, thermal and mechanical behavior of neat polypropylene, 40 wt.% talc-filled ... more In the present paper, thermal and mechanical behavior of neat polypropylene, 40 wt.% talc-filled polypropylene and 5 wt.% silicate-clay filled polypropylene nanocomposite were tested and evaluated. TGA and DSC results show that filling the talc particle or nano clay into polypropylene can increase the decomposition temperature, but has no effect on glass transition temperature and melt temperature. Tensile results show that 40 wt.% talc particle can increase the modulus, but decrease the yield strength, 5 wt.% nano clay can improve both modulus and yield strength by 90 and 5%, respectively. Fatigue results show that the nanophased polypropylene exhibited the highest fatigue performance, and fatigue strength coefficient, σ f , of nanophased polypropylene was 13.3% higher than that of the neat propyropylene and 50% higher than that of talc-filled polypropylene. At last, a three-parameter non-linear constitutive equation was developed to describe strain rate depend strain softening behavior of three materials.

Materials Science and Engineering: A, 2009

In this study, mechanical test have been performed on neat epoxy, 0.1%, 0.2%, 0.3% and 0.4% CNTs ... more In this study, mechanical test have been performed on neat epoxy, 0.1%, 0.2%, 0.3% and 0.4% CNTs reinforced epoxy. Testing results indicated that the highest improvement in strength and fracture toughness was obtained with 0.3wt% CNT loading. SEM pictures of fracture surface showed that, during the failure process, cleavage steps are formed when the crack propagation changed direction as it crossed CNTs. The flat cleavage planes were formed by the network of cleavage steps and roughness of fracture surface increased after infusing of CNT. Based on this mechanism, a photo micrographic method was established to determine dispersion of CNT in epoxy by measuring the distance between two cleavage steps. Statistical analysis results indicated that the average distance of two cleavage steps decreased with increasing CNT content. Two dispersion peaks in 0.3% system indicate initialization of agglomeration.

Materials Science and Engineering: A, 2006

The present study investigates the effect of SiO 2 nanoparticle on the thermal and mechanical pro... more The present study investigates the effect of SiO 2 nanoparticle on the thermal and mechanical properties of nylon-6. Firstly, nanoparticles with 0, 1, and 2 wt.% loading were dry-mixed with nylon-6 by mechanical means and extruded into filaments using a single screw extruder. Then, tensile tests were performed on the single filament at the strain rate range of 0.02-2 min −1. Experimental results show that both neat and nanophased nylon-6 were strain rate strengthening materials. The tensile modulus, yield strength, and ultimate tensile strength (UTS) all increased with increasing strain rate. Experimental results also show that infusing nanoparticles into nylon-6 can increase tensile modulus, yield strength, hardening modulus, and UTS. Forty-five percent enhancement in tensile modulus and 26% enhancement in UTS were observed in the 2 wt.% system as compared with neat nylon-6. At the same time, thermal properties of neat and nanophased nylon-6 were characterized by TGA and DSC. TGA thermograms have shown that the nanoparticle infused systems are more thermally stable. DSC studies also have indicated that there is a moderate increase in T g without a distinct shift in the melting endotherm for the nanophased systems. At last, based on the tensile test results, a nonlinear constitutive equation was developed to describe strain rate sensitive behavior of neat and nanophased nylon-6.

Materials Letters, 2006

In the present investigation, we have developed a novel technique to fabricate nanocomposite mate... more In the present investigation, we have developed a novel technique to fabricate nanocomposite materials containing SC-15 epoxy resin and K-10 montmorillonite clay. A high-intensity ultrasonic liquid processor was used to obtain a homogeneous molecular mixture of epoxy resin and nano-clay. The clays were infused into the part A of SC-15 (Diglycidylether of Bisphenol A) through sonic cavitations and then mixed with part B of SC-15 (cycloaliphatic amine hardener) using a high-speed mechanical agitator. The trapped air and reaction volatiles were removed from the mixture using high-vacuum. DMA, TGA and three-point bending tests were performed on unfilled, 1 wt.%, 2 wt.%, 3 wt.% and 4 wt.% clay-filled SC-15 epoxy to identify the loading effect on thermal and mechanical properties of the composites. The flexural results indicate that 2.0 wt.% loading of clay in epoxy resin showed the highest improvement in flexural strength as compared to the neat system. DMA studies also revealed that 2.0 wt.% doped system exhibit the highest storage modulus and T g as compared to neat and other loading percentages. However, TGA results show that thermal stability of composite is insensitive to the clay content.

Materials Letters, 2010

Effect of inclusions size and weight fraction on flexural strength and failure mode of composite ... more Effect of inclusions size and weight fraction on flexural strength and failure mode of composite containing SC-15 epoxy resin and TiO2 particles has been studied in this investigation. The sizes of particles varied from macro (0.02mm) to nano (5nm) scale, and these particles were infused into the part-A of SC-15 through sonic cavitations and then mixed with part-B of SC-15

Journal of Materials Science, 2007

In the present investigation, dynamic mechanical analysis (DMA), thermo gravimetric analysis (TGA... more In the present investigation, dynamic mechanical analysis (DMA), thermo gravimetric analysis (TGA), tensile tests, fatigue tests and the single edge notch tensile (SENT) tests were performed on unfilled, 1, 2 and 3 wt.% vapor grown carbon nanofiber (CNF) filled SC-15 epoxy to identify the loading effect on thermal and mechanical properties of the composites. DMA studies revealed that filling the 3% carbon nanofiber into epoxy can produce 65% enhancement in storage modulus at room temperature and 6°C increase in T g. However, TGA results show that thermal stability of composite is insensitive to the CNF content. Tensile tests were carried out at the strain rate range from 0.02 min-1 to 2 min-1. Results show that CNF/ epoxy are strain rate sensitive materials, the modulus and tensile strength increased with increasing of strain rate. Experimental results also indicate that modulus of the nanophased epoxy increases continuously with increasing CNF content. But the 2% CNF infusion system exhibit maximum enhancement in tensile strength, fatigue performance and fracture toughness as compared with other system.

Journal of Materials Processing Technology, 2007

In the present investigation, DMA and flexural tests were performed on unfilled, 1wt.%, 2wt.%, 3w... more In the present investigation, DMA and flexural tests were performed on unfilled, 1wt.%, 2wt.%, 3wt.% and 4wt.% clay filled SC-15 epoxy to identify the loading effect on thermal and mechanical properties of the matrix. Thermal and mechanical test results indicated that 2.0wt% clay/epoxy systems showed the highest improvement in the storage modulus and flexural strength. After that, the nanophased matrix

Journal of Applied Polymer Science, 2006

ABSTRACT

In this study, 1wt% carbon nanofiber (CNF) and TiO 2 nanoparticles have been infused in part A of... more In this study, 1wt% carbon nanofiber (CNF) and TiO 2 nanoparticles have been infused in part A of polyurethane (PUR) foam by ultrasound sonication, then mixed with part B of PUR foam by mechanical stirrer. Tensile, flexural and compression tests were performed to evaluate mechanical performance of neat and nanophased PUR foams. Experimental results show that CNF reinforced PUR foam exhibit the highest tensile strength, flexural strength and compression strength as compared with other PUR Foams.

Journal of Materials Science, 2003

In this paper, yield and fatigue behavior of a polypropylene nanocomposite and a polyamide-6 nano... more In this paper, yield and fatigue behavior of a polypropylene nanocomposite and a polyamide-6 nanocomposite has been studied. The Eyring equation was used to model the temperature and strain rate sensitivity of the yield strengths of these two nanocomposites. Both activation volume and activation energy of the polypropylene nanocomposite were higher than those of the polyamide-6 nanocomposite. The fatigue strength

Materials Science and Engineering: A, 2007

h i g h l i g h t s MWCNTs and Cu were ball milled with a variation of milling times. Thermal con... more h i g h l i g h t s MWCNTs and Cu were ball milled with a variation of milling times. Thermal conductivity and tensile strength of the PMCs were measured. Cu reinforced HDPE showed thermal conductivity improvement ratios of up to 2.7. MWCNT/HDPE showed higher thermal conductivity than MWCNT/PP. MWCNT/HDPE was found to be mechanically stronger than Cu/HDPE.

Journal of Composites, 2014

Tensile stress-strain behavior coupled with fractography was used to investigate the weld-line st... more Tensile stress-strain behavior coupled with fractography was used to investigate the weld-line strength of an injection molded 40 w% talc-filled polypropylene. The relationship between processing conditions, microstructure, and tensile strength was established. Fracture surface of the weld line exhibited skin-core morphology with different degrees of talc particle orientations in the core and in the skin. Experimental results also showed that the thickness of the core decreased and the thickness of the skins increased with increasing melt temperature and increasing hold pressure, which resulted in an increase of yield strength and yield strain with increasing melt temperature and increasing hold pressure. Finally, a three-parameter nonlinear constitutive model was developed to describe the strain softening behavior of the weld-line strength of talc-filled polypropylene. The parameters in this model are the modulus E, the strain exponent m, and the compliance factor β. The simulated ...

Materials Science and Engineering: A, 2005

Tensile experiments conducted on an injection molded short E-glass fiber reinforced polyamide-6,6... more Tensile experiments conducted on an injection molded short E-glass fiber reinforced polyamide-6,6 composite show that flow-induced fiber orientation due to injection molding caused higher tensile properties in the direction of flow compared to normal to the direction of flow. The presence of weld line reduced the modulus, tensile strength and failure strain of the material. Both elastic modulus and tensile strength of the material increased with increasing strain rate, indicating that this composite was a strain rate dependent material. Based on the experimental results, a nonlinear damage model was established to describe the stress-strain relationship of the short fiber reinforced polyamide-6,6. The parameters in this model are tensile modulus E, Weibull scale parameter σ 0 and Weibull shape parameter β. It is shown that the Weibull shape parameter, β, does not depend on strain rate, and can be regarded a constant; however, the Weibull scale parameter, σ 0 , is a linear function of log (strain rate).

Journal of Materials Science

Tensile mechanical behavior of T300 fiber bundles and M40J fiber bundles have been studied in the... more Tensile mechanical behavior of T300 fiber bundles and M40J fiber bundles have been studied in the strain rate range from 0.001 1/s to 1300 1/s and complete stress strain curves were obtained. Results show that both ultimate strength and failure strain of two materials are strain rate insensitive, and T300 fiber and M40J fiber can be regarded as strain rate insensitive materials. On basis of the fiber bundles model and the statistic theory of fiber strength, single Weibull distribution model and bimodal Weibull distribution model have been developed to describe mechanical behavior of fiber bundles. And a method for determine the statistic parameters of fibers by tensile tests of fiber bundles is established, too. The simulated stress strain curves from the model are in good agreement with the test data. Simulated results show that the strength of T300 fiber can be described by single Weibull distribution function, and the strength of M40J fiber should be described by bimodal Weibull ...

Materials Science and Engineering: A, 2008

In the present paper, vapor-grown carbon nanofibers were mechanically dry-mixed with polypropylen... more In the present paper, vapor-grown carbon nanofibers were mechanically dry-mixed with polypropylene powder and extruded into filaments with a single screw extruder. Then tensile tests were performed on the single filament at a strain rate range from 0.02min−1 to 2min−1. Results indicate that both neat and nanophased polypropylene were strain rate-strengthening material. The tensile modulus and yield strength both increased

Volume 13: Processing and Engineering Applications of Novel Materials, 2007

In this study, electrical, thermal and mechanical properties of multi-walled carbon nanotubes (CN... more In this study, electrical, thermal and mechanical properties of multi-walled carbon nanotubes (CNTs) reinforced Epon 862 epoxy have been evaluated. Firstly, 0.1 wt%, 0.2 wt%, 0.3 wt%, and 0.4 wt% CNT were infused into epoxy through a high intensity ultrasonic liquid processor and then mixed with EpiCure curing agent W using a high speed mechanical agitator. The trapped air and reaction volatiles were removed from the mixture using a high vacuum. Neat epoxy sample also was made as reference. Electrical conductivity, dynamic mechanical analysis (DMA, three point bending tests and fracture tests were performed on unfilled, CNT-filled epoxy to identify the loading effect on the properties of composites. Experimental results show significant improvement in electric conductivity. The resistivity of epoxy decreased to 15Ωm with 0.4% CNT. DMA studies revealed that filling the carbon nanotube into epoxy can produce a 90% enhancement in storage modulus and a 17° C increase in Tg, but CNT has ...

Applied Mechanics, 2005

In this paper, loading and loading-unloading tests of carbon fiber reinforced aluminum laminates ... more In this paper, loading and loading-unloading tests of carbon fiber reinforced aluminum laminates (CRALL) have been carried out in a tensile impact apparatus, and quasi-static tensile tests have been performed on a MTS-810 machine. Complete stress-strain curves of composite in the strain rate range from 0.001–1200 1/s have been obtained. Experimental results show that CRALL composite is a strain rate sensitivity material, the tensile strength and failure strain both increased with increasing strain rate. A linear strain hardening model has been combined with Weibull distribution function to establish a constitutive equation for CRALL. The simulated stress-strain curves from model are in good agreement with the test data. The analysis of the model shows that the Weibull scale parameter, σ0, increased with increasing strain rate, but Weibull shape parameter, β, can be regarded as a constant.

International Journal of Nanoscience, 2008

A novel sonochemical method is developed to coat multi-walled carbon nanotubes (MWCNTs) on expand... more A novel sonochemical method is developed to coat multi-walled carbon nanotubes (MWCNTs) on expandable thermoplastic (acrylonitrile and methylacrylonitrile polymer) microspheres (Expancel). These polymeric thermoplastic microspheres were further fabricated in a form of foam panels using a compression molding technique. The test coupons were cut precisely from the as-prepared panels and characterized by scanning electron microscopy (SEM), X-ray diffraction, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The SEM studies have shown that the MWCNTs are well dispersed over the entire volume of the matrix with minimal agglomeration. The foam cell structures are well-ordered, spherical in shape, and uniform in size. The TGA and DSC analyses indicate that the nanocomposite foam samples are thermally more stable than the corresponding neat foam samples. The compression tests have been carried out for both nanocomposite and neat foam samples. These test results s...

Materials, Nondestructive Evaluation, and Pressure Vessels and Piping, 2006

In the present study, effect of vapor grown carbon nanofiber on the mechanical and thermal proper... more In the present study, effect of vapor grown carbon nanofiber on the mechanical and thermal properties of polypropylene was investigated. Firstly, nanofibers were dry-mixed with polypropylene powder and extruded into filaments by using a single screw extruder. Then the tensile tests were performed on the single filament at the strain rate range from 0.02/min to 2/min. Experiments results show that both neat and nano-phased polypropylene were strain rate strengthening material. The tensile modulus and yield strength both increased with increasing strain rate. Experimental results also show that infusing nanofiber into polypropylene can increase tensile modulus and yield strength, but decrease the failure strain. At the same time, thermal properties of neat and nano-phased polypropylene were characterized by TGA. TGA results have showed that the nanophased system is more thermally stable. At last, a nonlinear constitutive equation has been developed to describe strain rate sensitive behavior of neat and nano-phased polypropylene.© 2006 ASME

Volume 8: Mechanics of Solids, Structures and Fluids; Vibration, Acoustics and Wave Propagation, 2011

In this study, the nanophased epoxy with 2 wt.% clay was utilized in a vacuum assisted resin tran... more In this study, the nanophased epoxy with 2 wt.% clay was utilized in a vacuum assisted resin transfer molding (VARTM) set up with carbon fabric to fabricate laminated composites. The effectiveness of clay addition on mechanical properties of composites has been evaluated by tensile, flexural and fatigue test. The tensile and flexural strengths improved by 5.7% and 13.5%, respectively as compared to the neat composite. The fatigue strength was also improved significantly. Based on the experimental result, a linear damage model combined with the Weibull distribution function has been established to describe static failure processing of neat and nanophased carbon/epoxy. The simulated stress strain curves from the model are in good agreement with the test data. Simulated results show that damage processing of neat and nanophased carbon/epoxy described by bimodal Weibull distribution function.

Materials Science and Engineering: A, 2005

In the present paper, thermal and mechanical behavior of neat polypropylene, 40 wt.% talc-filled ... more In the present paper, thermal and mechanical behavior of neat polypropylene, 40 wt.% talc-filled polypropylene and 5 wt.% silicate-clay filled polypropylene nanocomposite were tested and evaluated. TGA and DSC results show that filling the talc particle or nano clay into polypropylene can increase the decomposition temperature, but has no effect on glass transition temperature and melt temperature. Tensile results show that 40 wt.% talc particle can increase the modulus, but decrease the yield strength, 5 wt.% nano clay can improve both modulus and yield strength by 90 and 5%, respectively. Fatigue results show that the nanophased polypropylene exhibited the highest fatigue performance, and fatigue strength coefficient, σ f , of nanophased polypropylene was 13.3% higher than that of the neat propyropylene and 50% higher than that of talc-filled polypropylene. At last, a three-parameter non-linear constitutive equation was developed to describe strain rate depend strain softening behavior of three materials.

Materials Science and Engineering: A, 2009

In this study, mechanical test have been performed on neat epoxy, 0.1%, 0.2%, 0.3% and 0.4% CNTs ... more In this study, mechanical test have been performed on neat epoxy, 0.1%, 0.2%, 0.3% and 0.4% CNTs reinforced epoxy. Testing results indicated that the highest improvement in strength and fracture toughness was obtained with 0.3wt% CNT loading. SEM pictures of fracture surface showed that, during the failure process, cleavage steps are formed when the crack propagation changed direction as it crossed CNTs. The flat cleavage planes were formed by the network of cleavage steps and roughness of fracture surface increased after infusing of CNT. Based on this mechanism, a photo micrographic method was established to determine dispersion of CNT in epoxy by measuring the distance between two cleavage steps. Statistical analysis results indicated that the average distance of two cleavage steps decreased with increasing CNT content. Two dispersion peaks in 0.3% system indicate initialization of agglomeration.

Materials Science and Engineering: A, 2006

The present study investigates the effect of SiO 2 nanoparticle on the thermal and mechanical pro... more The present study investigates the effect of SiO 2 nanoparticle on the thermal and mechanical properties of nylon-6. Firstly, nanoparticles with 0, 1, and 2 wt.% loading were dry-mixed with nylon-6 by mechanical means and extruded into filaments using a single screw extruder. Then, tensile tests were performed on the single filament at the strain rate range of 0.02-2 min −1. Experimental results show that both neat and nanophased nylon-6 were strain rate strengthening materials. The tensile modulus, yield strength, and ultimate tensile strength (UTS) all increased with increasing strain rate. Experimental results also show that infusing nanoparticles into nylon-6 can increase tensile modulus, yield strength, hardening modulus, and UTS. Forty-five percent enhancement in tensile modulus and 26% enhancement in UTS were observed in the 2 wt.% system as compared with neat nylon-6. At the same time, thermal properties of neat and nanophased nylon-6 were characterized by TGA and DSC. TGA thermograms have shown that the nanoparticle infused systems are more thermally stable. DSC studies also have indicated that there is a moderate increase in T g without a distinct shift in the melting endotherm for the nanophased systems. At last, based on the tensile test results, a nonlinear constitutive equation was developed to describe strain rate sensitive behavior of neat and nanophased nylon-6.

Materials Letters, 2006

In the present investigation, we have developed a novel technique to fabricate nanocomposite mate... more In the present investigation, we have developed a novel technique to fabricate nanocomposite materials containing SC-15 epoxy resin and K-10 montmorillonite clay. A high-intensity ultrasonic liquid processor was used to obtain a homogeneous molecular mixture of epoxy resin and nano-clay. The clays were infused into the part A of SC-15 (Diglycidylether of Bisphenol A) through sonic cavitations and then mixed with part B of SC-15 (cycloaliphatic amine hardener) using a high-speed mechanical agitator. The trapped air and reaction volatiles were removed from the mixture using high-vacuum. DMA, TGA and three-point bending tests were performed on unfilled, 1 wt.%, 2 wt.%, 3 wt.% and 4 wt.% clay-filled SC-15 epoxy to identify the loading effect on thermal and mechanical properties of the composites. The flexural results indicate that 2.0 wt.% loading of clay in epoxy resin showed the highest improvement in flexural strength as compared to the neat system. DMA studies also revealed that 2.0 wt.% doped system exhibit the highest storage modulus and T g as compared to neat and other loading percentages. However, TGA results show that thermal stability of composite is insensitive to the clay content.

Materials Letters, 2010

Effect of inclusions size and weight fraction on flexural strength and failure mode of composite ... more Effect of inclusions size and weight fraction on flexural strength and failure mode of composite containing SC-15 epoxy resin and TiO2 particles has been studied in this investigation. The sizes of particles varied from macro (0.02mm) to nano (5nm) scale, and these particles were infused into the part-A of SC-15 through sonic cavitations and then mixed with part-B of SC-15

Journal of Materials Science, 2007

In the present investigation, dynamic mechanical analysis (DMA), thermo gravimetric analysis (TGA... more In the present investigation, dynamic mechanical analysis (DMA), thermo gravimetric analysis (TGA), tensile tests, fatigue tests and the single edge notch tensile (SENT) tests were performed on unfilled, 1, 2 and 3 wt.% vapor grown carbon nanofiber (CNF) filled SC-15 epoxy to identify the loading effect on thermal and mechanical properties of the composites. DMA studies revealed that filling the 3% carbon nanofiber into epoxy can produce 65% enhancement in storage modulus at room temperature and 6°C increase in T g. However, TGA results show that thermal stability of composite is insensitive to the CNF content. Tensile tests were carried out at the strain rate range from 0.02 min-1 to 2 min-1. Results show that CNF/ epoxy are strain rate sensitive materials, the modulus and tensile strength increased with increasing of strain rate. Experimental results also indicate that modulus of the nanophased epoxy increases continuously with increasing CNF content. But the 2% CNF infusion system exhibit maximum enhancement in tensile strength, fatigue performance and fracture toughness as compared with other system.

Journal of Materials Processing Technology, 2007

In the present investigation, DMA and flexural tests were performed on unfilled, 1wt.%, 2wt.%, 3w... more In the present investigation, DMA and flexural tests were performed on unfilled, 1wt.%, 2wt.%, 3wt.% and 4wt.% clay filled SC-15 epoxy to identify the loading effect on thermal and mechanical properties of the matrix. Thermal and mechanical test results indicated that 2.0wt% clay/epoxy systems showed the highest improvement in the storage modulus and flexural strength. After that, the nanophased matrix

Journal of Applied Polymer Science, 2006

ABSTRACT

In this study, 1wt% carbon nanofiber (CNF) and TiO 2 nanoparticles have been infused in part A of... more In this study, 1wt% carbon nanofiber (CNF) and TiO 2 nanoparticles have been infused in part A of polyurethane (PUR) foam by ultrasound sonication, then mixed with part B of PUR foam by mechanical stirrer. Tensile, flexural and compression tests were performed to evaluate mechanical performance of neat and nanophased PUR foams. Experimental results show that CNF reinforced PUR foam exhibit the highest tensile strength, flexural strength and compression strength as compared with other PUR Foams.

Journal of Materials Science, 2003

In this paper, yield and fatigue behavior of a polypropylene nanocomposite and a polyamide-6 nano... more In this paper, yield and fatigue behavior of a polypropylene nanocomposite and a polyamide-6 nanocomposite has been studied. The Eyring equation was used to model the temperature and strain rate sensitivity of the yield strengths of these two nanocomposites. Both activation volume and activation energy of the polypropylene nanocomposite were higher than those of the polyamide-6 nanocomposite. The fatigue strength

Materials Science and Engineering: A, 2007

h i g h l i g h t s MWCNTs and Cu were ball milled with a variation of milling times. Thermal con... more h i g h l i g h t s MWCNTs and Cu were ball milled with a variation of milling times. Thermal conductivity and tensile strength of the PMCs were measured. Cu reinforced HDPE showed thermal conductivity improvement ratios of up to 2.7. MWCNT/HDPE showed higher thermal conductivity than MWCNT/PP. MWCNT/HDPE was found to be mechanically stronger than Cu/HDPE.

Journal of Composites, 2014

Tensile stress-strain behavior coupled with fractography was used to investigate the weld-line st... more Tensile stress-strain behavior coupled with fractography was used to investigate the weld-line strength of an injection molded 40 w% talc-filled polypropylene. The relationship between processing conditions, microstructure, and tensile strength was established. Fracture surface of the weld line exhibited skin-core morphology with different degrees of talc particle orientations in the core and in the skin. Experimental results also showed that the thickness of the core decreased and the thickness of the skins increased with increasing melt temperature and increasing hold pressure, which resulted in an increase of yield strength and yield strain with increasing melt temperature and increasing hold pressure. Finally, a three-parameter nonlinear constitutive model was developed to describe the strain softening behavior of the weld-line strength of talc-filled polypropylene. The parameters in this model are the modulus E, the strain exponent m, and the compliance factor β. The simulated ...