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Changgok Chang - One of the best experts on this subject based on the ideXlab platform.
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effect of the hydrophilic Nanofiller loading on the mechanical properties and the microtensile bond strength of an ethanol based one bottle dentin adhesive
Journal of Biomedical Materials Research Part B, 2005Co-Authors: Chung Moon Um, Myunghwan Oh, Changgok ChangAbstract:This study evaluated the hypothesis that if hydrophilic Nanofillers were dispersed evenly within the adhesive layer under moist conditions, adding them to a one-bottle dentin adhesive might improve the mechanical properties of the adhesive layer, and accordingly increase the bond strength. The flexural strength (FS), the degree of conversion (DC), and the microtensile bond strength (MTBS) to the dentin of four experimental ethanol-based one-bottle dentin adhesives containing 0, 0.5, 1.0, and 3.0 wt % of 12-nm hydrophilic fumed silica were evaluated, and the distribution of the Nanofillers were compared using transmission electron microscopy (TEM). Although the Nanofiller content did not affect the DC, the FS tended to increase with increasing Nanofiller content. The MTBS appeared to increase when up to 1.0 wt % of the Nanofillers were added, but they were statistically not significant. However, when 3.0 wt % of the Nanofillers were added, the MTBS decreased significantly comparing to the adhesive containing 0.5 wt % Nanofillers (p < 0.05). The TEM image suggested that if the Nanofillers within the adhesive were 3.0 wt % and applied to a wet dentin surface, they aggregated easily into large clusters and would decrease the MTBS. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 284–291, 2005
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effect of the hydrophilic Nanofiller loading on the mechanical properties and the microtensile bond strength of an ethanol based one bottle dentin adhesive
Journal of Biomedical Materials Research, 2005Co-Authors: Chung Moon Um, Myunghwan Oh, Changgok ChangAbstract:This study evaluated the hypothesis that if hydrophilic Nanofillers were dispersed evenly within the adhesive layer under moist conditions, adding them to a one-bottle dentin adhesive might improve the mechanical properties of the adhesive layer, and accordingly increase the bond strength. The flexural strength (FS), the degree of conversion (DC), and the microtensile bond strength (MTBS) to the dentin of four experimental ethanol-based one-bottle dentin adhesives containing 0, 0.5, 1.0, and 3.0 wt % of 12-nm hydrophilic fumed silica were evaluated, and the distribution of the Nanofillers were compared using transmission electron microscopy (TEM). Although the Nanofiller content did not affect the DC, the FS tended to increase with increasing Nanofiller content. The MTBS appeared to increase when up to 1.0 wt % of the Nanofillers were added, but they were statistically not significant. However, when 3.0 wt % of the Nanofillers were added, the MTBS decreased significantly comparing to the adhesive containing 0.5 wt % Nanofillers (p < 0.05). The TEM image suggested that if the Nanofillers within the adhesive were 3.0 wt % and applied to a wet dentin surface, they aggregated easily into large clusters and would decrease the MTBS.
Chung Moon Um - One of the best experts on this subject based on the ideXlab platform.
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effect of the hydrophilic Nanofiller loading on the mechanical properties and the microtensile bond strength of an ethanol based one bottle dentin adhesive
Journal of Biomedical Materials Research Part B, 2005Co-Authors: Chung Moon Um, Myunghwan Oh, Changgok ChangAbstract:This study evaluated the hypothesis that if hydrophilic Nanofillers were dispersed evenly within the adhesive layer under moist conditions, adding them to a one-bottle dentin adhesive might improve the mechanical properties of the adhesive layer, and accordingly increase the bond strength. The flexural strength (FS), the degree of conversion (DC), and the microtensile bond strength (MTBS) to the dentin of four experimental ethanol-based one-bottle dentin adhesives containing 0, 0.5, 1.0, and 3.0 wt % of 12-nm hydrophilic fumed silica were evaluated, and the distribution of the Nanofillers were compared using transmission electron microscopy (TEM). Although the Nanofiller content did not affect the DC, the FS tended to increase with increasing Nanofiller content. The MTBS appeared to increase when up to 1.0 wt % of the Nanofillers were added, but they were statistically not significant. However, when 3.0 wt % of the Nanofillers were added, the MTBS decreased significantly comparing to the adhesive containing 0.5 wt % Nanofillers (p < 0.05). The TEM image suggested that if the Nanofillers within the adhesive were 3.0 wt % and applied to a wet dentin surface, they aggregated easily into large clusters and would decrease the MTBS. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 284–291, 2005
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effect of the hydrophilic Nanofiller loading on the mechanical properties and the microtensile bond strength of an ethanol based one bottle dentin adhesive
Journal of Biomedical Materials Research, 2005Co-Authors: Chung Moon Um, Myunghwan Oh, Changgok ChangAbstract:This study evaluated the hypothesis that if hydrophilic Nanofillers were dispersed evenly within the adhesive layer under moist conditions, adding them to a one-bottle dentin adhesive might improve the mechanical properties of the adhesive layer, and accordingly increase the bond strength. The flexural strength (FS), the degree of conversion (DC), and the microtensile bond strength (MTBS) to the dentin of four experimental ethanol-based one-bottle dentin adhesives containing 0, 0.5, 1.0, and 3.0 wt % of 12-nm hydrophilic fumed silica were evaluated, and the distribution of the Nanofillers were compared using transmission electron microscopy (TEM). Although the Nanofiller content did not affect the DC, the FS tended to increase with increasing Nanofiller content. The MTBS appeared to increase when up to 1.0 wt % of the Nanofillers were added, but they were statistically not significant. However, when 3.0 wt % of the Nanofillers were added, the MTBS decreased significantly comparing to the adhesive containing 0.5 wt % Nanofillers (p < 0.05). The TEM image suggested that if the Nanofillers within the adhesive were 3.0 wt % and applied to a wet dentin surface, they aggregated easily into large clusters and would decrease the MTBS.
Myunghwan Oh - One of the best experts on this subject based on the ideXlab platform.
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effect of the hydrophilic Nanofiller loading on the mechanical properties and the microtensile bond strength of an ethanol based one bottle dentin adhesive
Journal of Biomedical Materials Research Part B, 2005Co-Authors: Chung Moon Um, Myunghwan Oh, Changgok ChangAbstract:This study evaluated the hypothesis that if hydrophilic Nanofillers were dispersed evenly within the adhesive layer under moist conditions, adding them to a one-bottle dentin adhesive might improve the mechanical properties of the adhesive layer, and accordingly increase the bond strength. The flexural strength (FS), the degree of conversion (DC), and the microtensile bond strength (MTBS) to the dentin of four experimental ethanol-based one-bottle dentin adhesives containing 0, 0.5, 1.0, and 3.0 wt % of 12-nm hydrophilic fumed silica were evaluated, and the distribution of the Nanofillers were compared using transmission electron microscopy (TEM). Although the Nanofiller content did not affect the DC, the FS tended to increase with increasing Nanofiller content. The MTBS appeared to increase when up to 1.0 wt % of the Nanofillers were added, but they were statistically not significant. However, when 3.0 wt % of the Nanofillers were added, the MTBS decreased significantly comparing to the adhesive containing 0.5 wt % Nanofillers (p < 0.05). The TEM image suggested that if the Nanofillers within the adhesive were 3.0 wt % and applied to a wet dentin surface, they aggregated easily into large clusters and would decrease the MTBS. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 284–291, 2005
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effect of the hydrophilic Nanofiller loading on the mechanical properties and the microtensile bond strength of an ethanol based one bottle dentin adhesive
Journal of Biomedical Materials Research, 2005Co-Authors: Chung Moon Um, Myunghwan Oh, Changgok ChangAbstract:This study evaluated the hypothesis that if hydrophilic Nanofillers were dispersed evenly within the adhesive layer under moist conditions, adding them to a one-bottle dentin adhesive might improve the mechanical properties of the adhesive layer, and accordingly increase the bond strength. The flexural strength (FS), the degree of conversion (DC), and the microtensile bond strength (MTBS) to the dentin of four experimental ethanol-based one-bottle dentin adhesives containing 0, 0.5, 1.0, and 3.0 wt % of 12-nm hydrophilic fumed silica were evaluated, and the distribution of the Nanofillers were compared using transmission electron microscopy (TEM). Although the Nanofiller content did not affect the DC, the FS tended to increase with increasing Nanofiller content. The MTBS appeared to increase when up to 1.0 wt % of the Nanofillers were added, but they were statistically not significant. However, when 3.0 wt % of the Nanofillers were added, the MTBS decreased significantly comparing to the adhesive containing 0.5 wt % Nanofillers (p < 0.05). The TEM image suggested that if the Nanofillers within the adhesive were 3.0 wt % and applied to a wet dentin surface, they aggregated easily into large clusters and would decrease the MTBS.
Marwan Alhaik - One of the best experts on this subject based on the ideXlab platform.
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a review on polymeric nanocomposites effect of hybridization and synergy on electrical properties
2018Co-Authors: Masoud Safdari, Marwan AlhaikAbstract:Abstract This chapter reviews recent efforts for achieving synergy of the electrical conductivity in nanocomposites based on carbon Nanofillers. Hybrid polymeric nanocomposites based on carbon nanotubes (CNTs) and graphite nanoplatelets (GNPs) are of particular interest for their enhanced transport properties, over mono-Nanofiller composite systems. Besides reviewing the effects of the processing of nanocomposites on archiving synergy of electrical conductivity, we also review several recently developed computational models based on percolation analysis. The results suggest that both the models, and the experimental observations, confirm the presence of the synergy effect for the electrical properties of the hybrid composites. Particularly, several computational and experimental studies suggest incorporating a miniscule amount of auxiliary Nanofiller boosts the electrical conductivity of the hybrid composites by several orders of magnitudes. The review affirms that the particle agglomeration, poor dispersion, interfaces, and lack of proper functionalization severely affect the microstructure and hence the properties of the hybrid nanocomposites and are the root causes for the conflicting results in the literature.
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electrical conductivity of synergistically hybridized nanocomposites based on graphite nanoplatelets and carbon nanotubes
Nanotechnology, 2012Co-Authors: Masoud Safdari, Marwan AlhaikAbstract:In this investigation, a recent model for assessing the electrical conductivity of nanocomposites comprising a single type of conductive Nanofiller was expanded to cases with mixtures of Nanofillers. The extended model considers electron tunneling as the effective mechanism for insulator-conductor transition. The model was validated with relevant experimental data based on a mono-Nanofiller. Using the extended model, the effective electrical conductivity of a nanocomposite comprising both graphite nanoplatelets and carbon nanotubes was investigated. It was observed that the hybridized nanocomposites filled with a mixture of these conductive Nanofillers attain, synergistically, enhanced electrical conductivities at lower volume fractions. The lower filler contents assist in preserving the intrinsic properties of the host polymer in support of several applications. It was also observed that the relative aspect ratios of the conductive fillers play significant roles on the electrical conductivity of the hybrid nanocomposite. Simulations revealed that, generally, the addition of minimal amounts of a higher aspect ratio auxiliary phase to a lower aspect ratio main phase enhances the electrical conductivity of the composite by orders of magnitude.
Liberata Guadagno - One of the best experts on this subject based on the ideXlab platform.
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nanofilled epoxy adhesive for structural aeronautic materials
Composites Part B-engineering, 2014Co-Authors: Umberto Vietri, Liberata Guadagno, Marialuigia Raimondo, Luigi Vertuccio, Khalid LafdiAbstract:Abstract The aim of this work was to develop new adhesive formulations based on epoxy/nanostructured carbon forms. Different types of Nanofillers were dispersed into an epoxy matrix for developing toughened epoxy paste aeronautic adhesives. The reinforced adhesives were used for bonding carbon nanofilled/epoxy composite adherents. Data were also compared to the results obtained both for the unfilled adhesive and/or adherents. Tensile butt joint, and single lap joint samples were prepared to measure mechanical strength and adhesion properties of the different joint configurations. The inclusion of carbon Nanofillers inside the epoxy adhesive caused a significant improvement in the bond strength of the joints, changing the failure mode of joints in single lap joint shear tests. Significant change of the bonding performance was observed as the weight fraction of carbon nano-fillers increased from 1.37 to 5 wt/wt%. Adhesion between nano-reinforcements and adherents substrate was studied by means of Scanning Electron Microscopy.
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development of epoxy mixtures for application in aeronautics and aerospace
RSC Advances, 2014Co-Authors: Liberata Guadagno, Marialuigia Raimondo, Luigi Vertuccio, Vittoria Vittoria, Carlo Naddeo, Salvatore Russo, Biagio De Vivo, Patrizia Lamberti, Giovanni Spinelli, Vincenzo TucciAbstract:This work describes a successful attempt toward the development of composite materials based on nanofilled epoxy resins for the realization of structural aeronautic components providing efficient lightning strike protection. The epoxy matrix is prepared by mixing a tetrafunctional epoxy precursor with a reactive diluent which allows the moisture content to be reduced and facilitates the Nanofiller dispersion step. The reactive diluent also proves to be beneficial for improving the curing degree of nanofilled epoxy mixtures. It increases the mobility of reactive groups resulting in a higher cure degree than the epoxy precursor alone. This effect is particularly advantageous for nanofilled resins where higher temperature treatments are needed, compared to the unfilled resin, to reach the same cure degree. As Nanofiller, different carbon nanostructured fiber-shaped fillers are embedded in the epoxy matrix with the aim of improving the electrical properties of the resin. The results highlight a strong influence of the Nanofiller nature on the electrical properties especially in terms of electrical percolation threshold (EPT) and electrical conductivity beyond the EPT. Among the analyzed Nanofillers, the highest electrical conductivity is obtained by using multiwalled carbon nanotubes (MWCNTs) and heat-treated carbon nanofibers (CNFs). The achieved results are analyzed by considering the Nanofiller morphological parameters and characteristics with respect to the impact on their dispersion effectiveness.
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Development of multifunctional carbon fiber reinforced composites (CFRCs) - Manufacturing process
'AIP Publishing', 2014Co-Authors: Liberata Guadagno, G. Barra, F. De Nicola, M. Raimondo, Umberto Vietri, Luigi Vertuccio, Ruggero Volponi, Giovanni Cosentino, Andrea Grilli, Paola SpenaAbstract:This work describes a successful attempt toward the development of CFRCs based on nanofilled epoxy resins. The epoxy matrix was prepared by mixing a tetrafunctional epoxy precursor with a reactive diluent which allows to reduce the viscosity of the initial epoxy precursor and facilitate the Nanofiller dispersion step. As Nanofiller, multiwall carbon nanotubes (MWCNTs) were embedded in the epoxy matrix with the aim of improving the electrical properties of the resin used to manufacture CFRCs. Panels were manufactured by Resin Film Infusion (RFI) using a non-usual technique to infuse a nano-filled resin into a carbon fiber dry preform
