The effect of thermally developed SiC@SiO2 core-shell structured nanoparticles on the mechanical, thermal and UV-shielding properties of polyimide composites
“…Owing to the stretching vibrations of hydroxyl, a weak band is emerged at 3400 cm −1 , which confirm the Si-OH groups on SiC surfaces. 31,32 Moreover, these bands also can be clearly observed in the spectra of r-GO/SiC sample, and the C-O, O-C-O, and O-H groups bands of r-GO/SiC sample indicating that there was also a partial reduction of GO, and its high intensity characteristic bands is due to the overlapping of the r-GO and SiC spectrum.Figure 4.The FT-IR spectra of (a) GO, (b) r-GO, (c) SiC, and (d) r-GO/SiC.…”
The effective means to solve material wear is to develop self-lubricating composite materials with excellent tribological, thermal, and mechanical properties. Herein, the composites of reduced graphene oxide (r-GO) nanosheet decorated with Silicon Carbide (SiC) were facilely prepared with employing a silane coupling agent, and the corresponding r-GO/SiC/thermosetting polyimide (r-GO/SiC/TPI) nanocomposite films were obtained by in situ polymerization method. The mechanical, tribological, and thermal properties of these nanocomposite films were investigated. When the content of r-GO/SiC was at 1.0 wt%, the compression strength and compression modulus of the composite increased by 37.7% and 47.3%, respectively, which were much higher than that of TPI composites addition of r-GO or SiC alone. Furthermore, r-GO/SiC/TPI composites also exhibited the lowest wear rate and friction coefficient in these reinforced TPI nanocomposites. When the content of r-GO/SiC was 0.8 wt%, particularly, the friction coefficient and wear rate of r-GO/SiC/TPI decreased by 22.8% and 79.8% compared to pure TPI, respectively. Additionally, trace amount r-GO/SiC hybrids also significantly enhance the thermal stability of TPI matrix. Compared to the polyimide composites reinforced by common nano-scale inorganic fillers, the outstanding mechanical and tribological properties of this r-GO/SiC/PI composites could be attributed to the ball on plane structure of GO/SiC, which lead to crack reflection, strength increment. These r-GO/SiC/TPI composites demonstrate the promising potential to be used as high-performance tribological materials in industry applications.
“…Owing to the stretching vibrations of hydroxyl, a weak band is emerged at 3400 cm −1 , which confirm the Si-OH groups on SiC surfaces. 31,32 Moreover, these bands also can be clearly observed in the spectra of r-GO/SiC sample, and the C-O, O-C-O, and O-H groups bands of r-GO/SiC sample indicating that there was also a partial reduction of GO, and its high intensity characteristic bands is due to the overlapping of the r-GO and SiC spectrum.Figure 4.The FT-IR spectra of (a) GO, (b) r-GO, (c) SiC, and (d) r-GO/SiC.…”
The effective means to solve material wear is to develop self-lubricating composite materials with excellent tribological, thermal, and mechanical properties. Herein, the composites of reduced graphene oxide (r-GO) nanosheet decorated with Silicon Carbide (SiC) were facilely prepared with employing a silane coupling agent, and the corresponding r-GO/SiC/thermosetting polyimide (r-GO/SiC/TPI) nanocomposite films were obtained by in situ polymerization method. The mechanical, tribological, and thermal properties of these nanocomposite films were investigated. When the content of r-GO/SiC was at 1.0 wt%, the compression strength and compression modulus of the composite increased by 37.7% and 47.3%, respectively, which were much higher than that of TPI composites addition of r-GO or SiC alone. Furthermore, r-GO/SiC/TPI composites also exhibited the lowest wear rate and friction coefficient in these reinforced TPI nanocomposites. When the content of r-GO/SiC was 0.8 wt%, particularly, the friction coefficient and wear rate of r-GO/SiC/TPI decreased by 22.8% and 79.8% compared to pure TPI, respectively. Additionally, trace amount r-GO/SiC hybrids also significantly enhance the thermal stability of TPI matrix. Compared to the polyimide composites reinforced by common nano-scale inorganic fillers, the outstanding mechanical and tribological properties of this r-GO/SiC/PI composites could be attributed to the ball on plane structure of GO/SiC, which lead to crack reflection, strength increment. These r-GO/SiC/TPI composites demonstrate the promising potential to be used as high-performance tribological materials in industry applications.
“…The composite (0.10 wt % TiO 2 @DPP) possessed great fire retardance and better mechanical properties, as shown in Figure 7 . Mekuria et al [ 44 ] developed SiC@SiO 2 by the thermal oxidation of SiC nanoparticles, and the SiC@SiO 2 particles were amino-functionalized by APTMS (3-aminopropyltrimethoxysilane) to achieve the uniform dispersion of the nanoparticles in the PI matrix and prevent stacking and aggregating. As a result, the tensile strength and Young’s modulus were significantly improved compared to the neat PI (77.1% and 96.6% higher, respectively).…”
Owing to the diverse composition, adjustable performance, and synergistic effect among components, core–shell micro/nanoparticles have been widely applied in the field of tribology in recent years. The strong combination with the matrix and the good dispersion of reinforcing fillers in the composites could be achieved through the design of core–shell structural particles based on the reinforcing fillers. In addition, the performance of chemical mechanical polishing could be improved by optimizing the shell material coated on the abrasive surface. The physical and chemical state of the core–shell micro/nanoparticles played important effects on the friction and wear properties of materials. In this paper, the synthesis methods, the tribological applications (acted as solid/liquid lubricant additive, chemical mechanical polishing abrasives and basic units of lubricant matrix), and the functionary mechanisms of core–shell micro/nanoparticles were systematically reviewed, and the future development of core–shell micro/nanoparticles in tribology was also prospected.
“…Furthermore, the DSC curve (blue) demonstrates two endothermic curves, the first small one at 280 • C and the second big one at 360 • C, which correspond to the two thermal decompositions of PMMA and P(MAA-co-EGDMA), respectively. The residual mass at 850 • C is the remaining carbon, approximately 1.5% of the initial mass [41].…”
The aim of this study is to synthesize an organic core-shell co-polymer with a different glass transition temperature (Tg) between the core and the shell that can be used for several applications such as the selective debonding of coatings or the release of encapsulated materials. The co-polymer was synthesized using free radical polymerization and was characterized with respect to its morphology, composition and thermal behavior. The obtained results confirmed the successful synthesis of the co-polymer copolymer poly(methyl methacrylate)@poly(methacrylic acid-co-ethylene glycol dimethacrylate), PMMA@P(MAA-co-EGDMA), which can be used along with water-based solvents. Furthermore, the Tg of the polymer’s core PMMA was 104 °C, while the Tg of the shell P(MAA-co-EGDMA) was 228 °C, making it appropriate for a wide variety of applications. It is worth mentioning that by following this specific experimental procedure, methacrylic acid was copolymerized in water, as the shell of the copolymer, without forming a gel-like structure (hydrogel), as happens when a monomer is polymerized in aqueous media, such as in the case of super-absorbent polymers. Moreover, the addition and subsequent polymerization of the monomer methyl methacrylate (MAA) into the mixture of the already polymerized PMMA resulted in a material that was uniform in size, without any agglomerations or sediments.
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