Sepiolite （S9, B10, B20, B40） and boehmite have been added to an intumecent flame retardant （IFR） system to produce the halogen-free and fire-resistant ethylene-vinyl acetate copolymer （EVM） rubber. The rubber c...Sepiolite （S9, B10, B20, B40） and boehmite have been added to an intumecent flame retardant （IFR） system to produce the halogen-free and fire-resistant ethylene-vinyl acetate copolymer （EVM） rubber. The rubber contains ammonium polyphosphate （APP） as acid source, double pentaerythritol （D-PER） as carbon source and melamine （MN） as gas source. The effects of nano-filler sepiolite and boehmite on the fire-resistant property of EVM rubber based on IFR system were investigated. The test results show that the system with nano-filler of sepiolite B10 has the best fire-resistant property. The process of smoke emission and thermal decomposition, the element composition of char surface and the micro morphology of intumecent char layer of the EVM IFR system with nano-filler were also studied by NBS chamber, thermogravimetric （TG） analysis, X- ray photoelectron spectroscopy （XPS） and scanning electron microscope （SEM）.展开更多
Purpose: The mechanical strength of polymethyl methacrylate (PMMA) remains far from ideal for maintaining the longevity of denture. The purpose of this study was to evaluate the effect of Zirconium oxide (ZrO2) nanofi...Purpose: The mechanical strength of polymethyl methacrylate (PMMA) remains far from ideal for maintaining the longevity of denture. The purpose of this study was to evaluate the effect of Zirconium oxide (ZrO2) nanofillers powder with different concentration (1.5%, 3%, 5% and 7%) on the flexural strength, fracture toughness, and hardness of heat-polymerized acrylic resin. Materials and methods: Zirconium oxide powders with different concentrations (1.5%, 3%, 5% and 7%) were incorporated into heat-cure acrylic resin (PMMA) and processed with optimal condition (2.5:1 Powder/monomer ratio, conventional packing method and water bath curing for 2 hours at 95。C) to fabricate test specimens of PMMA of dimensions (50 × 30 × 30 mm) for the flexural strength, fracture toughness, and (50 × 30 × 30 mm) were fabricated for measuring hardness. PMMA without additives was prepared as a test control. Three types of mechanical tests;flexural strength, fracture toughness and hardness were carried out on the samples. The recorded values of flexural strength in (MPa), fracture toughness in (MPa.m1/2), and hardness (VHN) were collected, tabulated and statistically analyzed. One way analysis of variance (ANOVA) and Tukey’s tests were used for testing the significance between the means of tested groups which are statistically significant when the P value ≤ 0.05. Results: Addition of Zirconium oxide nanofillers to PMMA significantly increased the flexural strength, fracture toughness and hardness. Conclusion: These results indicate that Zirconium oxide nanofillers added to PMMA has a potential as a reliable denture base material with increased flexural strength, fracture toughness, and hardness. According to the results of the present study, the best mechanical properties were achieved by adding 7%wt ZrO2 concentration.展开更多
Polymer blend electrolytes, where PEO-PMMA polymer blend is used as polymer host matrix, doped with AgNO3 and plasticized with ethylene carbonate (EC) and Al2O3 as nano-filler were synthesized using the solution cast ...Polymer blend electrolytes, where PEO-PMMA polymer blend is used as polymer host matrix, doped with AgNO3 and plasticized with ethylene carbonate (EC) and Al2O3 as nano-filler were synthesized using the solution cast techniques. The polymer films were characterized by impedance spectroscopy, XRD, DSC, SEM, FT-IR and ionic transport mea-surements. The results indicate an enhancement in conductivity of PEO-PMMA-AgNO3-EC polymer electrolytes. The ionic conductivity of the polymer films is also found to increase with temperature. Electrical properties of polymer films in the framework of dielectric and modulus formalism are studied and展开更多
A novel method for preparing conductive polyethylene （PE） composites has been developed. In the method, the powder of low melting point metal alloy （LMPA） is filled into the PE matrix by using twin screw extruder ...A novel method for preparing conductive polyethylene （PE） composites has been developed. In the method, the powder of low melting point metal alloy （LMPA） is filled into the PE matrix by using twin screw extruder at a temperature below the melting point of the LMPA, and followed by a die drawing process at a temperature around the melting point of the metal alloy. It has been found that die drawing process, repeating the die drawing process and adding nano-fillers, such as montmorillonite （MMT） and multi-wall carbon nanotubes （MWCNTs）, all help reduce the metal particle size in the PE matrix, thus improve the conductivity of the composite. The conductivity improvement is attributed to an increased number of the smaller metal particles. Therefore, conductive composites of polymer/metal alloy/nano-filler with high conductivity are possible to be prepared by using the new method.展开更多
This work outlines the characterization of epoxy resin[Bisphenol A-(epichlorhydrin):epoxy]and hardener[N(3-dimethylaminopropyl)-1,3-propylenediamine]with various inorganic nano-fillers.Dielectric characterizations of ...This work outlines the characterization of epoxy resin[Bisphenol A-(epichlorhydrin):epoxy]and hardener[N(3-dimethylaminopropyl)-1,3-propylenediamine]with various inorganic nano-fillers.Dielectric characterizations of epoxy,hardener,neat epoxy(epoxy+hardener)and nano-epoxy(nano-filler+neat epoxy)composites loaded with 1 wt.%of inorganic nano-fillers(SiO_(2),Al_(2)O_(3),TiO_(2)and ZnO)were carried out using precision LCR meter,over the frequency range of 1 kHz-2 MHz at a constant temperature of 300.15 K.The structural information of nano-fillers,neat epoxy and nano-epoxy composites was understood by Fourier transform infrared spectroscopy and by XRD.Moreover,hardness and shear strength(shear punch)were also determined in order to gain additional information about the mechanical properties of epoxy composite.Influence of inorganic nano-fillers on the dielectric properties,structural chemistry and mechanical properties of neat epoxy composite is discussed thoroughly in this study.展开更多
Eco-friendly and biodegradable novel hydrogel were prepared by blending and solution casting method. The designed hydrogel is based on chitosan/ PEG600/Gurgam with carbon nanofiller along silane crosslinked (TEOS) wit...Eco-friendly and biodegradable novel hydrogel were prepared by blending and solution casting method. The designed hydrogel is based on chitosan/ PEG600/Gurgam with carbon nanofiller along silane crosslinked (TEOS) with pH sensitive response to controlled release of drug in biomedical materials and agriculture industry. The various concentration of carbon nanofiller is used to analyze its effect on the fabricated hydrogel characteristics by using FTIR, SEM, TGA, swelling studies (water, buffer and ionic solution). Spectra of FTIR reflected both established and newly developed groups (like hydrogel). COOH group presence is clearly observed in this range in the carbon filler reinforced hydrogel. The SEM micrographs show that CPG0.003 had a collection of polysaccharide chains as thin helices, which is attributed to the increase in the size of porosity. TGA shows to increase concentration of nanofiller enhanced the thermal stability of the designed hydrogels at temperature 25˚C to 550˚C mass loss percentage decrease upto 20% and increase thermal stability. This pH response made these resultant hydrogels as fruitful competitor against the many reported controlled release application.展开更多
基金Sponsored by Project in National Key Technology R&D Program(2006BAE03B05-2)
文摘Sepiolite （S9, B10, B20, B40） and boehmite have been added to an intumecent flame retardant （IFR） system to produce the halogen-free and fire-resistant ethylene-vinyl acetate copolymer （EVM） rubber. The rubber contains ammonium polyphosphate （APP） as acid source, double pentaerythritol （D-PER） as carbon source and melamine （MN） as gas source. The effects of nano-filler sepiolite and boehmite on the fire-resistant property of EVM rubber based on IFR system were investigated. The test results show that the system with nano-filler of sepiolite B10 has the best fire-resistant property. The process of smoke emission and thermal decomposition, the element composition of char surface and the micro morphology of intumecent char layer of the EVM IFR system with nano-filler were also studied by NBS chamber, thermogravimetric （TG） analysis, X- ray photoelectron spectroscopy （XPS） and scanning electron microscope （SEM）.
文摘Purpose: The mechanical strength of polymethyl methacrylate (PMMA) remains far from ideal for maintaining the longevity of denture. The purpose of this study was to evaluate the effect of Zirconium oxide (ZrO2) nanofillers powder with different concentration (1.5%, 3%, 5% and 7%) on the flexural strength, fracture toughness, and hardness of heat-polymerized acrylic resin. Materials and methods: Zirconium oxide powders with different concentrations (1.5%, 3%, 5% and 7%) were incorporated into heat-cure acrylic resin (PMMA) and processed with optimal condition (2.5:1 Powder/monomer ratio, conventional packing method and water bath curing for 2 hours at 95。C) to fabricate test specimens of PMMA of dimensions (50 × 30 × 30 mm) for the flexural strength, fracture toughness, and (50 × 30 × 30 mm) were fabricated for measuring hardness. PMMA without additives was prepared as a test control. Three types of mechanical tests;flexural strength, fracture toughness and hardness were carried out on the samples. The recorded values of flexural strength in (MPa), fracture toughness in (MPa.m1/2), and hardness (VHN) were collected, tabulated and statistically analyzed. One way analysis of variance (ANOVA) and Tukey’s tests were used for testing the significance between the means of tested groups which are statistically significant when the P value ≤ 0.05. Results: Addition of Zirconium oxide nanofillers to PMMA significantly increased the flexural strength, fracture toughness and hardness. Conclusion: These results indicate that Zirconium oxide nanofillers added to PMMA has a potential as a reliable denture base material with increased flexural strength, fracture toughness, and hardness. According to the results of the present study, the best mechanical properties were achieved by adding 7%wt ZrO2 concentration.
文摘Polymer blend electrolytes, where PEO-PMMA polymer blend is used as polymer host matrix, doped with AgNO3 and plasticized with ethylene carbonate (EC) and Al2O3 as nano-filler were synthesized using the solution cast techniques. The polymer films were characterized by impedance spectroscopy, XRD, DSC, SEM, FT-IR and ionic transport mea-surements. The results indicate an enhancement in conductivity of PEO-PMMA-AgNO3-EC polymer electrolytes. The ionic conductivity of the polymer films is also found to increase with temperature. Electrical properties of polymer films in the framework of dielectric and modulus formalism are studied and
文摘A novel method for preparing conductive polyethylene （PE） composites has been developed. In the method, the powder of low melting point metal alloy （LMPA） is filled into the PE matrix by using twin screw extruder at a temperature below the melting point of the LMPA, and followed by a die drawing process at a temperature around the melting point of the metal alloy. It has been found that die drawing process, repeating the die drawing process and adding nano-fillers, such as montmorillonite （MMT） and multi-wall carbon nanotubes （MWCNTs）, all help reduce the metal particle size in the PE matrix, thus improve the conductivity of the composite. The conductivity improvement is attributed to an increased number of the smaller metal particles. Therefore, conductive composites of polymer/metal alloy/nano-filler with high conductivity are possible to be prepared by using the new method.
基金Authors are thankful to the funding agency DST,New Delhi for providing financial assistance,through the DST-FIST Projects(SR/FST/PSI-001/2006 and SR/FST/PSI-198/2014)Funding provided by UGC,New Delhi through DRSSAP Program Grants[Nos.F.530/10/DRS/2010(SAP-1)and F.530/17/DRS-II/2018(SAP-1)]is also gratefully acknowledged.Authors are also thankful to Prof.P.N.Gajjar,Head,Department of Physics,University School of Sciences,Gujarat University,Ahmedabad for his constant encouragement.
文摘This work outlines the characterization of epoxy resin[Bisphenol A-(epichlorhydrin):epoxy]and hardener[N(3-dimethylaminopropyl)-1,3-propylenediamine]with various inorganic nano-fillers.Dielectric characterizations of epoxy,hardener,neat epoxy(epoxy+hardener)and nano-epoxy(nano-filler+neat epoxy)composites loaded with 1 wt.%of inorganic nano-fillers(SiO_(2),Al_(2)O_(3),TiO_(2)and ZnO)were carried out using precision LCR meter,over the frequency range of 1 kHz-2 MHz at a constant temperature of 300.15 K.The structural information of nano-fillers,neat epoxy and nano-epoxy composites was understood by Fourier transform infrared spectroscopy and by XRD.Moreover,hardness and shear strength(shear punch)were also determined in order to gain additional information about the mechanical properties of epoxy composite.Influence of inorganic nano-fillers on the dielectric properties,structural chemistry and mechanical properties of neat epoxy composite is discussed thoroughly in this study.
文摘Eco-friendly and biodegradable novel hydrogel were prepared by blending and solution casting method. The designed hydrogel is based on chitosan/ PEG600/Gurgam with carbon nanofiller along silane crosslinked (TEOS) with pH sensitive response to controlled release of drug in biomedical materials and agriculture industry. The various concentration of carbon nanofiller is used to analyze its effect on the fabricated hydrogel characteristics by using FTIR, SEM, TGA, swelling studies (water, buffer and ionic solution). Spectra of FTIR reflected both established and newly developed groups (like hydrogel). COOH group presence is clearly observed in this range in the carbon filler reinforced hydrogel. The SEM micrographs show that CPG0.003 had a collection of polysaccharide chains as thin helices, which is attributed to the increase in the size of porosity. TGA shows to increase concentration of nanofiller enhanced the thermal stability of the designed hydrogels at temperature 25˚C to 550˚C mass loss percentage decrease upto 20% and increase thermal stability. This pH response made these resultant hydrogels as fruitful competitor against the many reported controlled release application.
