The paper presents a comparative study on the electric, dielectric and microwave properties of natural rubber based composites comprising dual phase fillers prepared from furnace carbon black or conductive carbon blac...The paper presents a comparative study on the electric, dielectric and microwave properties of natural rubber based composites comprising dual phase fillers prepared from furnace carbon black or conductive carbon black with a different amount of silica. It has been established that, the specifics of the carbon phase have a marked strong effect upon the properties mentioned above. The interpenetration of the two filler phases and the grade of isolation of the conductive carbon phase by the dielectric one depend on the ratio between them. On the other hand, that leads to a change in all properties of the studied composites, which allows tailoring those characteristics.展开更多
Natural rubber based composites containing different carbon nanofillers (fullerenes, carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs)) at different concentrations have been prepared. Their dielectric properti...Natural rubber based composites containing different carbon nanofillers (fullerenes, carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs)) at different concentrations have been prepared. Their dielectric properties (dielectric permittivity, dielectric loss) have been studied in the 1 - 12 GHz frequency range. Some factors (electromagnetic field frequency, fillers concentration, fillers intrinsic structure) influencing the dielectric behavior of the composites have been investigated. The dielectric properties of the developed natural rubber composites containing conductive fillers (fullerenes, CNTs, GNPs) indicate that these composites can be used as broadband microwave absorbing materials.展开更多
Different types of carbon-silica fillers were prepared via pyrolysis-cum-water vapor of waste green tires tread and impregnation method. Dual phase fillers have been characterized by energy dispersive X-ray (EDX) spec...Different types of carbon-silica fillers were prepared via pyrolysis-cum-water vapor of waste green tires tread and impregnation method. Dual phase fillers have been characterized by energy dispersive X-ray (EDX) spectroscopy in a scanning transmission electron microscope (STEM) or STEM-EDX. Phase distribution in hybrid fillers for rubber was investigated. The results achieved show that the conditions of obtaining influence the distribution and the location of the phases in the carbon-silica hybrid fillers as well as their most essential characteristics including specific area, oil absorption number, iodine adsorption number, ash content and others.展开更多
The development of carbon nanotubes based materials has been impeded by both their difficult dispersion in the polymer matrix and their high cost. The discovery of graphene and the subsequent development of graphene-b...The development of carbon nanotubes based materials has been impeded by both their difficult dispersion in the polymer matrix and their high cost. The discovery of graphene and the subsequent development of graphene-based polymer nanocomposites is an important addition in the area of nanoscience and technology. In this study the influence of graphene nanoparticles (GNP) in concentrations from 2.0 to 10.0 phr on the dielectric (dielectric permittivity, dielectric loss angle tangent) and microwave (reflection coefficient, attenuation coefficient, shielding effectiveness) properties of nanocomposites on the basis of natural rubber has been investigated in the wide frequency range (1 - 12 GHz). The results achieved allow recommending graphene as a filler for natural rubber based composites to afford specific dielectric and microwave properties, especially when their loading with the much more expensive carbon nanotubes is not possible.展开更多
Natural products from agricultural wastes are finding importance in the polymer industry due to their many advantages such as being lightweight,low cost and environmentally friendly.In the present study the potential ...Natural products from agricultural wastes are finding importance in the polymer industry due to their many advantages such as being lightweight,low cost and environmentally friendly.In the present study the potential of the two types of rice husk ash(RHA)prepared under different conditions as fillers in natural rubber-based elastomer composites was investigated.The fillers were prepared by rice husks incineration and characterized by means of X-ray powder diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),scanning electron microscope(SEM),Brunauer-Emmett-Teller(BET)specific surface area,Hg-porosimetry and N2-adsorption.The evaluation involved determining the vulcanization characteristics of the compounds and their physical and mechanical characteristics,resistance to thermal aging as well as the dynamic properties of the vulcanizates containing RHA.It has been found that the ash from rice husk has good potential as filler in elastomers,especially as a substitute for synthetic commercially available silica.RHA improves the grip on ice and snow better than standard silica and may be used in formulations for shoe soles used for winter sports,extreme hiking footwear,ski boot soles,winter tire protectors,etc.Its quality depends on the conditions under which rice husk is incinerated.It is recommended to run the process at a temperature not higher than 800°C.In particular,cases in which the vulcanizates contain biogenic silica have very interesting characteristics like improved modulus at 300%of elongation,lower residual elongation,higher mechanical loss angle tangent at 0°C and lower at 60°C,and are superior to those of the vulcanizates containing commercially available filler Ultrasil?7000 GR.展开更多
文摘The paper presents a comparative study on the electric, dielectric and microwave properties of natural rubber based composites comprising dual phase fillers prepared from furnace carbon black or conductive carbon black with a different amount of silica. It has been established that, the specifics of the carbon phase have a marked strong effect upon the properties mentioned above. The interpenetration of the two filler phases and the grade of isolation of the conductive carbon phase by the dielectric one depend on the ratio between them. On the other hand, that leads to a change in all properties of the studied composites, which allows tailoring those characteristics.
文摘Natural rubber based composites containing different carbon nanofillers (fullerenes, carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs)) at different concentrations have been prepared. Their dielectric properties (dielectric permittivity, dielectric loss) have been studied in the 1 - 12 GHz frequency range. Some factors (electromagnetic field frequency, fillers concentration, fillers intrinsic structure) influencing the dielectric behavior of the composites have been investigated. The dielectric properties of the developed natural rubber composites containing conductive fillers (fullerenes, CNTs, GNPs) indicate that these composites can be used as broadband microwave absorbing materials.
文摘Different types of carbon-silica fillers were prepared via pyrolysis-cum-water vapor of waste green tires tread and impregnation method. Dual phase fillers have been characterized by energy dispersive X-ray (EDX) spectroscopy in a scanning transmission electron microscope (STEM) or STEM-EDX. Phase distribution in hybrid fillers for rubber was investigated. The results achieved show that the conditions of obtaining influence the distribution and the location of the phases in the carbon-silica hybrid fillers as well as their most essential characteristics including specific area, oil absorption number, iodine adsorption number, ash content and others.
文摘The development of carbon nanotubes based materials has been impeded by both their difficult dispersion in the polymer matrix and their high cost. The discovery of graphene and the subsequent development of graphene-based polymer nanocomposites is an important addition in the area of nanoscience and technology. In this study the influence of graphene nanoparticles (GNP) in concentrations from 2.0 to 10.0 phr on the dielectric (dielectric permittivity, dielectric loss angle tangent) and microwave (reflection coefficient, attenuation coefficient, shielding effectiveness) properties of nanocomposites on the basis of natural rubber has been investigated in the wide frequency range (1 - 12 GHz). The results achieved allow recommending graphene as a filler for natural rubber based composites to afford specific dielectric and microwave properties, especially when their loading with the much more expensive carbon nanotubes is not possible.
文摘Natural products from agricultural wastes are finding importance in the polymer industry due to their many advantages such as being lightweight,low cost and environmentally friendly.In the present study the potential of the two types of rice husk ash(RHA)prepared under different conditions as fillers in natural rubber-based elastomer composites was investigated.The fillers were prepared by rice husks incineration and characterized by means of X-ray powder diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),scanning electron microscope(SEM),Brunauer-Emmett-Teller(BET)specific surface area,Hg-porosimetry and N2-adsorption.The evaluation involved determining the vulcanization characteristics of the compounds and their physical and mechanical characteristics,resistance to thermal aging as well as the dynamic properties of the vulcanizates containing RHA.It has been found that the ash from rice husk has good potential as filler in elastomers,especially as a substitute for synthetic commercially available silica.RHA improves the grip on ice and snow better than standard silica and may be used in formulations for shoe soles used for winter sports,extreme hiking footwear,ski boot soles,winter tire protectors,etc.Its quality depends on the conditions under which rice husk is incinerated.It is recommended to run the process at a temperature not higher than 800°C.In particular,cases in which the vulcanizates contain biogenic silica have very interesting characteristics like improved modulus at 300%of elongation,lower residual elongation,higher mechanical loss angle tangent at 0°C and lower at 60°C,and are superior to those of the vulcanizates containing commercially available filler Ultrasil?7000 GR.
