The present study focuses on the thermal response of carbon fiber-reinforced phenolic composites, where the matrix has been modified with different reinforcements. Two types of materials, multiwalled carbon nanotubes ...The present study focuses on the thermal response of carbon fiber-reinforced phenolic composites, where the matrix has been modified with different reinforcements. Two types of materials, multiwalled carbon nanotubes and zirconium diboride （ZrB2）, were used in a new design of mixture to produce the heat- resistant ablative composite system. The CNT/ZrB2/carbon/phenolic nanocomposite （Z/NT-CR） system corresponding to CNT/carbon/phenolic nanocomposite （NT-CR） showed a reasonable decrease in mass loss and the ablation rate as compared to carbon/phenolic composite （CR）. However, substantial drop in two factors was found for Z/NT-CR as compared to carbon/phenolic and NT-CR. Ablation mechanisms for all three composites were investigated by thermal gravimetric analysis in conjunction with micro- structural studies using a field emission scanning electron microscope. The microstructural studies revealed that CNTs acted as an ablation resistant phase for protection against 2000 ℃, and the conversion from ZrB2 to ZrO2 played an important role as an insulator in the performance of char layer in the ablation resistance.展开更多
In the maritime industry, cost-effective and lightweight Fiber Reinforced Polymer (FRP) composites offer excellent mechanical properties, design flexibility, and corrosion resistance. However, their reliability in har...In the maritime industry, cost-effective and lightweight Fiber Reinforced Polymer (FRP) composites offer excellent mechanical properties, design flexibility, and corrosion resistance. However, their reliability in harsh seawater conditions is a concern. Researchers address this by exploring three approaches: coating fiber surfaces, hybridizing fibers and matrices with or without nanofillers, and interply rearrangement. This study focuses on evaluating the synergistic effects of interply rearrangement of glass/carbon fibers and hybrid nanofillers, specifically Multi-walled carbon nanotubes (MWCNT) and Halloysite nanotubes (HNT). The aim is to enhance impact properties by minimizing moisture absorption. Hybrid nanocomposites with equal-weight proportions of two nanofillers: 0 wt.%, 1 wt.%, and 2 wt.% were exposed to seawater for 90 days. Experimental data was subjected to modelling through the application of Predictive Fick’s Law. The study found that the hybrid composite containing 2 wt.% hybrid nanofillers exhibited a 22.10% increase in impact performance compared to non-modified counterparts. After 90 days of seawater aging, the material exhibited enhanced resistance to moisture absorption (15.74%) and minimal reduction in impact strength (8.52%) compared to its dry strength, with lower diffusion coefficients.展开更多
Recycled polystyrene （PS） cups were chopped up and separately incorporated with multiwall carbon nanotubes （MWCNTs） and NiZn ferrite （Ni0.6Zn0.4Fe2O4） nanoparticles prior to electrospinning under different condi...Recycled polystyrene （PS） cups were chopped up and separately incorporated with multiwall carbon nanotubes （MWCNTs） and NiZn ferrite （Ni0.6Zn0.4Fe2O4） nanoparticles prior to electrospinning under different conditions. These nanoscale inclusions were initially dispersed well in dimethylformamide （DMF）, and then known amounts of the recycled PS pieces were added to the dispersions prior to 30 min of sonication followed by 4 h of high-speed agitation at 750 r/min. The thermal, dielectric, surface hydrophobic, and magnetic properties of the resultant nanocomposite fibers were determined by thermal comparative, capacitance bridge, vibrating sample magnetometer （VSM）, and goniometer techniques, respectively. Test results confirmed that the physical properties of recycled nanofibers were significantly increased as a function of the inclusion concentrations, which may be because of their excellent properties. The consumption of polymeric products as well as their waste materials has dramatically grown worldwide. Although plastic recycling, reprocessing, and reusing rates are growing, the physical properties and economic value of recycled plastics are significantly low. Consequently, this work provides a detailed explanation of how to improve recycled plastics, making them into highly valued new nanoproducts for various industrial applications, including filtration, textile, transportation, construction, and energy.展开更多
A composite paste electrode based on Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF)—initially synthesized by solgel method—and multiwall carbon nanotube (MWCNT) as a cathode in fuel cells is developed. The composite pastes are pr...A composite paste electrode based on Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF)—initially synthesized by solgel method—and multiwall carbon nanotube (MWCNT) as a cathode in fuel cells is developed. The composite pastes are prepared by the direct mixing of BSCF:MWCNT at 90:10, 80:20 and 70:30 (% w/W). These electrodes are then characterized by the x-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherm, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The XRD and SEM confirm the inclusion and the uniform dispersal of the MWCNT within BSCF, respectively. The nitrogen adsorption isotherm study shows that the porosity of the composite paste electrode has been improved by two-fold from the BSCF electrode. The EIS and CV demonstrate that the higher ratios of MWCNT in the composites are critical in improving the electronic conductivity as well as the kinetics. It is also noticeable that the electrode has increased the catalysis of oxygen in 0.1 M KOH (pH 12.0). Cyclic voltammetric studies on the oxygen reduction reaction (ORR) suggest that the incorporation of MWCNT is vital in improving the electrode (cathode) properties of a fuel cell.展开更多
文摘The present study focuses on the thermal response of carbon fiber-reinforced phenolic composites, where the matrix has been modified with different reinforcements. Two types of materials, multiwalled carbon nanotubes and zirconium diboride （ZrB2）, were used in a new design of mixture to produce the heat- resistant ablative composite system. The CNT/ZrB2/carbon/phenolic nanocomposite （Z/NT-CR） system corresponding to CNT/carbon/phenolic nanocomposite （NT-CR） showed a reasonable decrease in mass loss and the ablation rate as compared to carbon/phenolic composite （CR）. However, substantial drop in two factors was found for Z/NT-CR as compared to carbon/phenolic and NT-CR. Ablation mechanisms for all three composites were investigated by thermal gravimetric analysis in conjunction with micro- structural studies using a field emission scanning electron microscope. The microstructural studies revealed that CNTs acted as an ablation resistant phase for protection against 2000 ℃, and the conversion from ZrB2 to ZrO2 played an important role as an insulator in the performance of char layer in the ablation resistance.
文摘In the maritime industry, cost-effective and lightweight Fiber Reinforced Polymer (FRP) composites offer excellent mechanical properties, design flexibility, and corrosion resistance. However, their reliability in harsh seawater conditions is a concern. Researchers address this by exploring three approaches: coating fiber surfaces, hybridizing fibers and matrices with or without nanofillers, and interply rearrangement. This study focuses on evaluating the synergistic effects of interply rearrangement of glass/carbon fibers and hybrid nanofillers, specifically Multi-walled carbon nanotubes (MWCNT) and Halloysite nanotubes (HNT). The aim is to enhance impact properties by minimizing moisture absorption. Hybrid nanocomposites with equal-weight proportions of two nanofillers: 0 wt.%, 1 wt.%, and 2 wt.% were exposed to seawater for 90 days. Experimental data was subjected to modelling through the application of Predictive Fick’s Law. The study found that the hybrid composite containing 2 wt.% hybrid nanofillers exhibited a 22.10% increase in impact performance compared to non-modified counterparts. After 90 days of seawater aging, the material exhibited enhanced resistance to moisture absorption (15.74%) and minimal reduction in impact strength (8.52%) compared to its dry strength, with lower diffusion coefficients.
基金the Department of Energy(DE-EE0004167)the Wichita State University for financial and technical support to the present work
文摘Recycled polystyrene （PS） cups were chopped up and separately incorporated with multiwall carbon nanotubes （MWCNTs） and NiZn ferrite （Ni0.6Zn0.4Fe2O4） nanoparticles prior to electrospinning under different conditions. These nanoscale inclusions were initially dispersed well in dimethylformamide （DMF）, and then known amounts of the recycled PS pieces were added to the dispersions prior to 30 min of sonication followed by 4 h of high-speed agitation at 750 r/min. The thermal, dielectric, surface hydrophobic, and magnetic properties of the resultant nanocomposite fibers were determined by thermal comparative, capacitance bridge, vibrating sample magnetometer （VSM）, and goniometer techniques, respectively. Test results confirmed that the physical properties of recycled nanofibers were significantly increased as a function of the inclusion concentrations, which may be because of their excellent properties. The consumption of polymeric products as well as their waste materials has dramatically grown worldwide. Although plastic recycling, reprocessing, and reusing rates are growing, the physical properties and economic value of recycled plastics are significantly low. Consequently, this work provides a detailed explanation of how to improve recycled plastics, making them into highly valued new nanoproducts for various industrial applications, including filtration, textile, transportation, construction, and energy.
文摘A composite paste electrode based on Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF)—initially synthesized by solgel method—and multiwall carbon nanotube (MWCNT) as a cathode in fuel cells is developed. The composite pastes are prepared by the direct mixing of BSCF:MWCNT at 90:10, 80:20 and 70:30 (% w/W). These electrodes are then characterized by the x-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherm, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The XRD and SEM confirm the inclusion and the uniform dispersal of the MWCNT within BSCF, respectively. The nitrogen adsorption isotherm study shows that the porosity of the composite paste electrode has been improved by two-fold from the BSCF electrode. The EIS and CV demonstrate that the higher ratios of MWCNT in the composites are critical in improving the electronic conductivity as well as the kinetics. It is also noticeable that the electrode has increased the catalysis of oxygen in 0.1 M KOH (pH 12.0). Cyclic voltammetric studies on the oxygen reduction reaction (ORR) suggest that the incorporation of MWCNT is vital in improving the electrode (cathode) properties of a fuel cell.
