Carbon nanofibers-based nanocomposites with silicon oxy-carbide matrix (original) (raw)
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Journal of the European Ceramic Society, 2020
The work presents the results of research on composite materials made of silicon-containing polymer-derived ceramic matrix composites (PDC-Cs) and nanocomposites (PDC-NCs). Carbon micro and nanofibers (CFs and CNFs) were used as reinforcements. The interactions between carbon micro and nanofibers and polysiloxane matrix, as well as interphase evolution mechanism in composite samples during their heating to 1000°C were studied. CF/resin and CNF/resin composites were prepared via liquid precursor infiltration process of unidirectionally aligned fibers. After heating to 700°C-800°C, decomposition of the resin in the presence of CNFs led to the formation of fiber/organic-inorganic composites with pseudo-plastic properties and improved oxidation resistance compared to as-prepared fiber/resin composites. The most favourable mechanical properties and oxidation resistance were obtained for composites and nanocomposites containing the maximum amount of carbon nanoparticles precipitated in the SiOC matrix during the heat treatment at 800°C. The precipitated carbon phase improves fiber/matrix adhesion of composites.
Characterization of carbon based nanofibers in nanocomposites and their applications
Now-a-days nanocomposites are used in almost all fields due to enhanced properties. Nanocomposite is composed of nanofibers and matrix. Due to large area to volume ratio nanofibers play a vital role in determining the characteristics of the nanocomposites. In this study it has been discussed about various properties of the carbon nanofibers in various matrix. From the study it is observed that mechanical properties like hardness, tensile strength are greatly affected by the size of nanofibers. By increasing CNF percentage in epoxy matrix it is observed that mechanical strength increased by 49%. Similarly other propertieslike physical property, electrical property, thermal property etc. get improved by the use of nanofibers. Materials having higher thermal conductivity such as Carbon and Diamond are introduced in the composite so as to increase thermal conductivity of nanocomposite. Generally the carbon based nanocompos-ites are used as supercapacitor, air purifier, battery and sensor.
Effect of Carbon Nanofiber Heat Treatment on Physical Properties of Polymeric Nanocomposites—Part I
Journal of Nanomaterials, 2007
The definition of a nanocomposite material has broadened significantly to encompass a large variety of systems made of dissimilar components and mixed at the nanometer scale. The properties of nanocomposite materials also depend on the morphology, crystallinity, and interfacial characteristics of the individual constituents. In the current work, vapor-grown carbon nanofibers were subjected to varying heat-treatment temperatures. The strength of adhesion between the nanofiber and an epoxy (thermoset) matrix was characterized by the flexural strength and modulus. Heat treatment to 1800 • C demonstrated maximum improvement in mechanical properties over that of the neat resin, while heat-treatment to higher temperatures demonstrated a slight decrease in mechanical properties likely due to the elimination of potential bonding sites caused by the elimination of the truncated edges of the graphene layers. Both the electrical and thermal properties of the resulting nanocomposites increased in conjunction with the increasing heat-treatment temperature.
Journal of Materials Science, 2011
For the first time, a series of carbon nanofiber (CNF)/polydimethylsiloxane(PDMS)-based nanocomposites was prepared using in situ polymerization technique by critical manipulation of factors, such as method of preparation and chemical modification of filler. Quantification of the degree of dispersion was done by introducing a dispersion degree parameter. Extent of dispersion was found to improve by amine modification of CNFs. Electrical conductivity was found to undergo profound increase when compared with that of the insulating base polymer. Aminemodified CNF-based nanocomposites showed percolation threshold at lower filler loading compared with unmodified CNF-based nanocomposites. These results of electrical properties measurements were correlated with the results of TEM analysis.
Effect of carbon nanofibers content on thermal properties of ceramic nanocomposites
Journal of Composite Materials, 2011
The thermal properties of carbon nanofibers (CNFs)-alumina and CNFs-zirconia nanocomposites densified by spark plasma sintering technique were evaluated. The influence of CNFs content and type of ceramic matrix on thermal conductivity of ceramic-CNFs materials, measured by the laser-flash method, was studied. The effect of CNFs depends noticeably on the ceramic component and thus, an increase of 83% and a decrease of 97% in thermal conductivity at room temperature is observed when 80 vol% of CNFs is added to ZrO2 and Al2O3, respectively. However, even if the thermal conductivity is lower, the efficiency of heat transfer to the environment in CNFs/Al2O3 nanocomposites is better than that corresponding to monolithic alumina. This behavior is due to CNFs arrangement in dense materials. Considering the low electrical resistivity for CNFs/ Al2O3 and CNFs/ ZrO2 materials (10−1–10−2 Ω·cm), these nanocomposites are promising candidates as thermoelectric materials that require low thermal co...
Journal of Applied Polymer Science, 2012
A series of carbon nanofiber (CNF)/polydimethylsiloxane (PDMS)-based nanocomposites was prepared by anionic ring opening polymerization of octamethylcyclotetrasiloxane (D 4 ) in presence of pristine CNF and aminemodified CNF. A detailed study of morphology-property relationship of the nanocomposites was carried out in order to understand the effect of chemical modification and loading of filler on property enhancement of the nanocomposites. An elaborate comparison of structure and properties was carried out for the nanocomposites prepared by in situ and conventional ex situ methods. Pronounced improvement in degree of dispersion of the fillers in the matrix on amine modification of CNFs was reflected in mechanical properties of the modified nanocomposites. Maximum upliftment in mechanical properties was observed for in situ prepared amine modified CNF/hydroxyl PDMS nanocomposites. For 8 phr filler loading, tensile strength increased by 370%, while tensile modulus showed an increase of 515% compared with the virgin elastomer. Furthermore, in situ prepared unmodified CNF/hydroxyl PDMS nanocomposites showed an increase of 141 C in temperature of maximum degradation (T max ) for 8 phr CNF loading. These results were correlated with the morphological analysis through transmission electron microscopic studies.
Journal of Applied Polymer Science, 2010
In this work, the dispersion of carbon nanofibers (CNFs) in an unsaturated polyester (UP) resin was performed by mean of the calendering process. The calendering process allows to obtain good dispersion of the nanoparticles, and, with respect to the other techniques, is also possible to scale it up at the industrial level. Optimization of the calendering conditions for the processing was carried out as a first step of this study. Optimization, in this case, means to reach the best dispersion level, as rapidly as possible and with the lowest amount of styrene evaporation. The dispersion level reached was investigated by the technique of scanning electron microscopy. The investigation on electric conductivity of the nanocomposites at different CNF concentrations has revealed that the electrical percolation threshold exists at around 0.3 wt %, where electrical conductivity switches from 10−13 to 10−7 S/cm. The rheological characterization has been performed to verify if the improved electrical properties are obtained at the expense of loss of workability, that is a significant increase of viscosity. Eventually, a mechanical characterization was carried out. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of Carbon Nanofiber-Matrix Adhesion on Polymeric Nanocomposite Properties—Part II
Journal of Nanomaterials, 2008
A successful integration of two independent phases with good adhesion is imperative for effective translation of superior carbon nanofiber filler properties into a physically superior carbon nanocomposite. Carbon nanofibers were subjected to electrochemical oxidation in 0.1 M nitric acid for varying times. The strength of adhesion between the nanofiber and an epoxy matrix was characterized by flexural strength and modulus. The surface functional groups formed and their concentration of nanofibers showed a dependence on the degree of oxidation. The addition of chemical functional groups on the nanofiber surface allows them to physically and chemically adhere to the continuous resin matrix. The chemical interaction with the continuous epoxy matrix results in the creation of an interphase region. The ability to chemically and physically interact with the epoxy region is beneficial to the mechanical properties of a carbon nanocomposite. A tailored degree of surface functionalization was found to increase adhesion to the matrix and increase flexural modulus.
Mechanical and thermal properties of epoxy/silicon carbide nanofiber composites
Polymers for Advanced Technologies, 2014
The silicon carbide (SiC) nanofibers (0.1, 0.25, and 0.5 phr), produced by self-propagating high-temperature synthesis (SHS), are used to reinforce the epoxy matrix cured with an anhydride hardener. Morphological studies reveal a better dispersion of SiC nanofibers and a good level of adhesion between nanofiber and the matrix in composites with lower (0.1 and 0.25 phr) nanofiber loading. The flexural studies show that a maximum increase in flexural properties is obtained for composites with 0.25 phr SiC nanofiber. The fracture toughness of epoxy is found to increase with the incorporation of SiC nanofibers, and 0.25 phr SiC nanofiber loading shows maximum fracture toughness value. The possible fracture mechanisms that exist in epoxy/SiC nanofiber composites have been investigated in detail. Thermogravimetric analysis reveals that SiC nanofibers are effective fillers to improve the thermal stability of epoxy matrix.