Effects of surface grafting of copper nanoparticles on the tensile and bonding properties of flax fibers

2017 ◽  
Vol 24 (5) ◽  
pp. 651-660 ◽  
Author(s):  
Zajna Sherief ◽  
Guijun Xian ◽  
Sabu Thomas ◽  
Anu Ajith
Keyword(s):  
Copper Nanoparticles ◽  
Copper Chloride ◽  
Chemical Reduction ◽  
Natural Fibers ◽  
Flax Fiber ◽  
Chloride Salt ◽  
Flax Fibers ◽  
Transmission Electron ◽  
Bonding Properties ◽  
Microbial Analysis

AbstractIn the present work, functionalized copper nanoparticles (FCuNPs) were grafted onto flax fibers, and the effects on the tensile properties, bonding strength to an epoxy resin, as well as the properties of the flax fiber-epoxy model composites were investigated. The copper nanoparticles were synthesized at ambient temperature by a chemical reduction method. The reduction of solution of copper chloride salt in the polyvinylalcohol medium was done by using sodium borohydrate. Ultraviolet-visible spectroscopy, transmission electron microscopy, and X-ray diffraction studies were used to characterize the size of the synthesized particles. The synthesized copper nanoparticles were applied to saturate the unidirectional flax natural fibers, whose surfaces were previously tailored with the cationic agent triethylammonium chloride. A remarkable improvement in the tensile strength by 75% and modulus by 50% for FCuNPs grafted flax fibers was found. Thermo-mechanical properties of the flax fiber reinforced epoxy composites were studied using DMTA. Finally, the anti-microbial analysis for composites was also conducted against Aspergillus niger spores, and enhanced anti-microbial performance was observed for treated fiber-based composites.

scholarly journals Tensile Behavior and Diffusion of Moisture through Flax Fibers by Desorption Method

2019 ◽  
Vol 11 (13) ◽  
pp. 3558 ◽  
Author(s):  
Swarda S. Radkar ◽  
Ali Amiri ◽  
Chad A. Ulven
Keyword(s):  
Diffusion Coefficients ◽  
Natural Fibers ◽  
Woven Fabrics ◽  
Tensile Behavior ◽  
Flax Fiber ◽  
Additional Absorption ◽  
Flax Fibers ◽  
Diffusion Rates ◽  
Desorption Method ◽  
And Diffusion

There has been a substantial increase in the usage of natural fibers and biodegradable polymers in composite materials due to the recent focus on sustainability of materials. Flax fibers have exhibited higher mechanical properties compared to most other natural fibers available. However, one of the major challenges faced in the use of flax fiber is its hydrophilicity. In this study, the tensile behavior of flax fiber tows removed from commercially available woven fabrics were investigated at different moisture levels. The breaking tenacity of fiber tows was shown to increase with an increase in moisture content of up to 25%. After this point, additional absorption of moisture resulted in a decrease of fiber tenacity. In addition, the diffusion process through flax fiber mat with different areal densities was investigated and the diffusion coefficients were determined using the desorption curves. Diffusion rates were not found to significantly change with varying areal densities of 200 to 400 gsm, but were significantly different when exposed to temperatures of 55 °C versus 80 °C.

scholarly journals Green Synthesis of Novel Jasmine Bud-Shaped Copper Nanoparticles

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Malathi Sampath ◽  
Ramya Vijayan ◽  
Ezhilarasu Tamilarasu ◽  
Abiraman Tamilselvan ◽  
Balasubramanian Sengottuvelan
Keyword(s):  
Copper Nanoparticles ◽  
Isonicotinic Acid ◽  
Chemical Reduction ◽  
Average Particle Size ◽  
Acid Hydrazide ◽  
Reducing Agent ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Atomic Force ◽  
Transmission Electron

Novel jasmine bud-shaped copper nanoparticles were synthesized by a green chemical reduction method using polyvinylpyrrolidone (PVP) as a capping agent, L-ascorbic acid (AA) as a reducing agent as well as antioxidant agent, isonicotinic acid hydrazide (INH) as a reducing agent, and water as a solvent at 60–70°C (pH-7) in the presence of air. The UV-Vis absorption maximum obtained is 573 nm. The crystal lattice (fcc) structure of Cu Nps was confirmed by X-ray diffraction (XRD). The novel jasmine bud shape was visualized in a transmission electron microscope (TEM). The height of single copper nanobud was 6.41 nm as measured by atomic force microscope (AFM). The average particle size 6.95 nm is obtained by XRD results. Antibacterial activity of the Cu nanobuds was evaluated by testing against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria.

scholarly journals Synthesis, characterization and evaluation of copper nanoparticles as agrochemicals against Phytophthora spp.

2019 ◽  
Vol 2 (6) ◽  
pp. 48-56
Author(s):  
Hoang Minh Hao ◽  
Cao Van Du ◽  
Duong Thi Ngoc Dung ◽  
Cao Xuan Chuong ◽  
Nguyen Thi Phuong Phong ◽  
...  
Keyword(s):  
Copper Nanoparticles ◽  
Chemical Reduction ◽  
Trisodium Citrate ◽  
Molar Ratio ◽  
In Vitro Test ◽  
Weight Percentage ◽  
Phytophthora Spp ◽  
Transmission Electron ◽  
Xrd Techniques

By using water as a solvent, copper nanoparticles (CuNPs) have been synthesized from copper sulfate via chemical reduction method in the presence of trisodium citrate dispersant and polyvinylpyrrolidone (PVP) as capping agent. The effects of the experimental parameters such as the concentration of reducing agent (NaBH4), reaction temperature, molar ratio of citrate/Cu2+ and weight percentage ratios of Cu2+/PVP on the CuNP sizes were studied. The size of CuNPs in a range of 31 nm was obtained at NaBH4 concentration of 0.2 M, 50oC, citrate/Cu2+ molar ratio of 1.0 and Cu2+/PVP weight percentage of 5%. The colloidal CuNPs were characterized by using UV–Visible spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD) techniques. The colloidal solution of CuNPs (3±1 nm) was investigated the potential against Phytophthora spp. which cause economically crop diseases. Under in vitro test conditions, the inhibition of Phytophthora spp. mycelia growth at three concentrations of CuNPs (10, 20, 30 ppm) after 48 hours are 90.18%, 91.87% and 100%, respectively. These results provided a simple and economical method to develop the CuNPs-based-fungicide.  

Synthesis of Copper Nanoparticles at Room Temperature Using Hydrazine in Glycerol

2013 ◽  
Vol 481 ◽  
pp. 21-26 ◽  
Author(s):  
Huei Ruey Ong ◽  
Maksudur Rahman Khan ◽  
Ridzuan Ramli ◽  
Rosli Mohd Yunus
Keyword(s):  
Copper Nanoparticles ◽  
Room Temperature ◽  
Red Wine ◽  
Copper Chloride ◽  
Reduction Process ◽  
Stability Study ◽  
Ambient Conditions ◽  
Transmission Electron ◽  
Average Size ◽  
Hydrazine Solution

Copper nanoparticles (CuNPs) have been prepared by the reduction of copper chloride in glycerol using hydrazine at ambient conditions. The reduction process takes place under vigorous stirring for 8 h. The formation of CuNPs and size were confirmed by UV/Vis analysis and TEM imaging respectively. The experiment result showed that, 7.062 mM of hydrazine solution and 0.0147 mM of Cu2+ solution were needed to synthesize narrow size monodisperseCuNPs.The presence of nanoparticle was found after an induction period of 4 h and further reaction time, complete Cu0 state nanoparticle was obtained as deep red wine colour was observed. Stability study of CuNPs showed that the nanoparticles were stable up to 4 days. The particle size of the nanoparticles have been analysed by transmission electron microscopy (TEM) and the average size of CuNPs was in the range 2 to 10 nm.

scholarly journals Glycerol Valorization over ZrO2-Supported Copper Nanoparticles Catalysts Prepared by Chemical Reduction Method

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1040
Author(s):  
Juan Garcés ◽  
Ramón Arrué ◽  
Néstor Novoa ◽  
Andreia F. Peixoto ◽  
Ricardo J. Chimentão
Keyword(s):  
Copper Nanoparticles ◽  
Reduction Method ◽  
Chemical Reduction ◽  
X Ray Diffraction ◽  
Chemical Reduction Method ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Region I ◽  
Temperature Programmed

Copper nanoparticles (NPs) and ZrO2-supported copper NPs (Cu NPs/ZrO2) were synthesized via a chemical reduction method applying different pH (4, 7 and 9) and evaluated in a glycerol dehydration reaction. Copper NPs were characterized with transmission electron microscopy (TEM) and UV–vis spectroscopy. Transmission electron microcopy (TEM) results revealed a homogeneous distribution of copper NPs. A hypsochromic shift was identified with UV–vis spectroscopy as the pH of the synthesis increased from pH = 4 to pH = 9. Zirconia-supported copper NPs catalysts were characterized using N2 physisorption, X-ray diffraction (XRD), TEM, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), temperature-programmed desorption of ammonia (NH3-TPD) and N2O chemisorption. The presence of ZrO2 in the chemical reduction method confirmed the dispersion of the copper nanoparticles. X-ray diffraction indicated only the presence of tetragonal zirconia patterns in the catalysts. XPS identified the Cu/Zr surface atomic ratio of the catalysts. TPR patterns showed two main peaks for the Cu NPS/ZrO2 pH = 9 catalyst; the first peak between 125 and 180 °C (region I) was ascribed to more dispersed copper species, and the second one between 180 and 250 °C (region II) was assigned to bulk CuO. The catalysts prepared at pH = 4 and pH = 7 only revealed reduction at lower temperatures (region I). Copper dispersion was determined by N2O chemisorption. With NH3-TPD it was found that Cu NPs/ZrO2 pH = 9 exhibited the highest total quantity of acidic sites and the highest apparent kinetic constant, with a value of 0.004 min−1. The different pH applied to the synthesis media of the copper nanoparticles determined the resultant copper dispersion on the ZrO2 support, providing active domains for glycerol conversion.

scholarly journals Nanofibrillated Cellulose and Copper Nanoparticles Embedded in Polyvinyl Alcohol Films for Antimicrobial Applications

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Tuhua Zhong ◽  
Gloria S. Oporto ◽  
Jacek Jaczynski ◽  
Changle Jiang
Keyword(s):  
Polyvinyl Alcohol ◽  
Copper Nanoparticles ◽  
Chemical Reduction ◽  
Antimicrobial Properties ◽  
Nanofibrillated Cellulose ◽  
Microbial Reduction ◽  
Nanocomposite Films ◽  
Transmission Electron ◽  
Average Size ◽  
Thermoplastic Resins

Our long-term goal is to develop a hybrid cellulose-copper nanoparticle material as a functional nanofiller to be incorporated in thermoplastic resins for efficiently improving their antimicrobial properties. In this study, copper nanoparticles were first synthesized through chemical reduction of cupric ions on TEMPO nanofibrillated cellulose (TNFC) template using borohydride as a copper reducing agent. The resulting hybrid material was embedded into a polyvinyl alcohol (PVA) matrix using a solvent casting method. The morphology of TNFC-copper nanoparticles was analyzed by transmission electron microscopy (TEM); spherical copper nanoparticles with average size of 9.2 ± 2.0 nm were determined. Thermogravimetric analysis and antimicrobial performance of the films were evaluated. Slight variations in thermal properties between the nanocomposite films and PVA resin were observed. Antimicrobial analysis demonstrated that one-week exposure of nonpathogenicEscherichia coliDH5αto the nanocomposite films results in up to 5-log microbial reduction.

scholarly journals FusariumAntifungal Activities of Copper Nanoparticles Synthesized by a Chemical Reduction Method

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Pham Van Viet ◽  
Hai Thi Nguyen ◽  
Thi Minh Cao ◽  
Le Van Hieu
Keyword(s):  
Copper Nanoparticles ◽  
Reduction Method ◽  
Chemical Reduction ◽  
Fungal Growth ◽  
Spherical Shape ◽  
Xrd Analysis ◽  
Chemical Reduction Method ◽  
Transmission Electron ◽  
Ft Ir ◽  
Average Size

We report on the process of synthesizing copper nanoparticles (Cu Nps) for a short reactive time by chemical reduction method with a support of CTAB reductive agent. Their properties were determined by ultraviolet-visible (UV-Vis) absorption spectrum, the X-ray (XRD) analysis, Fourier transform infrared spectroscopy (FT-IR), and Transmission Electron Microscopy (TEM) images. The antifungal activity of Cu Nps was evaluated by testing againstFusariumsp. The Cu Nps were obtained with the average size in the range of 20–50 nm having spherical shape. The survey shows that when Cu Nps were used at 450 ppm concentration in 9-day incubation, 93.98% of fungal growth was inhibited.

Study on the Preparation and Properties of Copper Nanoparticles and their Nanofluids

2011 ◽  
Vol 399-401 ◽  
pp. 606-609 ◽  
Author(s):  
Yang Li ◽  
Hua Qing Xie ◽  
Ji Feng Wang ◽  
Wei Yu
Keyword(s):  
Thermal Conductivity ◽  
Copper Nanoparticles ◽  
Base Fluid ◽  
High Speed ◽  
Chemical Reduction ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Copper Sulfate Pentahydrate ◽  
Transmission Electron ◽  
Wire Method

Nanoscale copper particles were synthesized by chemical reduction with polyvinyl pyrrolidone as dispersant, ascorbic acid as reduction agent, copper sulfate pentahydrate and ammonia as reagent. X-ray diffraction (XRD) analysis revealed that as-prepared copper nanoparticle was well crystallized without other impurities. Transmission electron microscopy (TEM) displayed that nanoscale coppers had homogenous distribution and the particle size was about 30~50 nm. Uniform and stable Cu-nanofluids were prepared by general stirring, high speed shear stirring and ultrasonic, with water/ethylene glycol as base fluid and as-synthesized copper nanoparticles as additives. The thermal conductivity of Cu-nanofluid was measured by a short-hot wire method. The results showed that the thermal conductivity of Cu-nanofluid was increased 8~9% compared to base fluid and the temperature had little effect on the enhancement of the thermal conductivity.

Diffraction Contrast Transmission Electron Microscopy on Flax Fiber Ultrathin Cross Sections

1988 ◽  
Vol 58 (7) ◽  
pp. 414-417 ◽  
Author(s):  
P. Näslund ◽  
R. Vuong ◽  
H. Chanzy ◽  
J. C. Jésior
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Micrographs ◽  
Cross Sections ◽  
Flax Fiber ◽  
Flax Fibers ◽  
Diffraction Contrast ◽  
Cutting Angle ◽  
Transmission Electron ◽  
Diamond Knife

The crystalline ultrastructure of flax fibers was studied using diffraction contrast transmission electron microscopy applied to ultrathin transverse sections obtained with an experimental diamond knife with a cutting angle of only 26.6°. This technique permitted the recording of electron micrographs where individual crystalline microfibrils could be seen in the middle of their tightly packed arrangements. The microfibrils in flax had diameters ranging from 1 to 4 nm; in some instances their angular and nearly square contours were revealed.

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