The Experts below are selected from a list of 11133 Experts worldwide ranked by ideXlab platform
Jian Wang - One of the best experts on this subject based on the ideXlab platform.
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Mixed Resin and carbon fibres surface treatment for preparation of carbon fibres composites with good interfacial bonding strength
Materials & Design, 2010Co-Authors: Jianlong Wang, Jian WangAbstract:Abstract The objective of this work is to improve the interlaminar shear strength of composites by mixing epoxy Resin and modifying carbon fibres. The effect of Mixed Resin matrix’s structure on carbon fibres composites was studied. Anodic oxidation treatment was used to modify the surface of carbon fibres. The tensile strength of multifilament and interlaminar shear strength of composites were investigated respectively. The morphologies of untreated and treated carbon fibres were characterized by scanning electron microscope and X-ray photoelectron spectroscopy. Surface analysis indicates that the amount of carbon fibres chemisorbed oxygen-containing groups, active carbon atom, the surface roughness, and wetting ability increases after treatment. The tensile strength of carbon fibres decreased little after treatment by anodic oxidation. The results show that the treated carbon fibres composites could possess excellent interfacial properties with Mixed Resins, and interlaminar shear strength of the composites is up to 85.41 MPa. The mechanism of Mixed Resins and treated carbon fibres to improve the interfacial property of composites is obtained.
Sunghun Kim - One of the best experts on this subject based on the ideXlab platform.
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the effect of preparation order on the crystal structure of yttria stabilized tetragonal zirconia polycrystal and the shear bond strength of dental Resin cements
Dental Materials, 2011Co-Authors: Jieun Moon, Jaibong Lee, Sunghun Kim, Yusung ChoiAbstract:Abstract Objectives The purpose of this study was to evaluate the effect of preparation order on the crystal structure of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) and the shear bond strength of dental Resin cements. Methods One-hundred fifty pre-sintered Y-TZP cylinders (O 9 mm × 13.5 mm) were prepared and divided into three groups (control group, SBS group and SAS group). Specimens in control group were not treated. Specimens in SBS group were sandblasted and then densely sintered, and specimens in SAS group were sintered in advance, and then sandblasted. The specimens were analyzed by X-ray diffractometry, confocal laser scanning microscopy and Energy dispersive X-ray spectroscopy before and after sandblasting. All specimens were embedded in polytetrafluoroethylene (PTFE) molds using PMMA and each group was divided into five subgroups. The Mixed Resin cements (Clearfil SA luting cement, Zirconite, Superbond C&B, Rely-X Unicem, and Multilink) were placed onto the Y-TZP surfaces using PTFE molds with O 3 mm × 3 mm, followed by storage in distilled water at 37 °C for 24 h, and thermocycling (5000 cycles at 5 °C and 55 °C with a 30 s dwelling time). All specimens were tested for the shear bond strengths with a universal testing machine, and fractured surfaces were evaluated by SEM. Statistical analysis was performed using one-way ANOVA and Scheffe comparison with α = .05. Results Sandblasting of the zirconia significantly increased shear bond strength of Resin cements, but the preparation order had no significant influence on the shear bond strength in both test groups. In SEM observation, the natures of the surface faceting of the zirconia grains were totally different between SBS and SAS groups. SBS group exhibited less monoclinic structures than SAS group. Significance Sandblasting of pre-sintered Y-TZP and then sintering may induce favorable proportion of tetragonal structures. This might have positive effect on the clinical performance of zirconia restorations.
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effect of sandblasting and various metal primers on the shear bond strength of Resin cement to y tzp ceramic
Dental Materials, 2010Co-Authors: Jeongyeon Yun, Jaibong Lee, Sunghun KimAbstract:Abstract Objectives This study was designed to evaluate the effect of sandblasting and metal primers on the shear bond strength of three commercial Resin cements to Yttria-Tetragonl Zirconia Polycrystal (Y-TZP) ceramics. Methods One hundred and twenty Y-TZP ceramic cylinders (O7 mm × 12 mm) were embedded in polytetrafluoroethylene (PTFE) molds using PMMA. The specimens were divided randomly into 12 groups ( n = 10), according to the surface treatments (control; sandblast-only; metal primer-only; sandblast + metal primer) and metal primer-Resin cements (Alloy primer – Panavia F 2.0, V-primer – Superbond C&B, Metaltite – M bond) rendered. The Mixed Resin cements were placed onto the treated zirconia surfaces in cylindrical shape (O3 mm × 3 mm) using PTFE molds. All specimens were thermocycled (5 and 55 °C, 5000 cycles) and subjected to shear bond strength test by a universal testing machine with a crosshead speed of 0.5 mm/min. All data were statistically analyzed using two-way ANOVA and multiple comparison Scheffe test ( α = 0.05), and SEM images of the fractured areas were used to evaluate the fracture mode. Results In Panavia F 2.0, the bond strength of the specimens treated with sandblasting and metal primer (Alloy primer) was significantly higher than those of the other subgroups. In Superbond C&B and M bond, sandblasting significantly increased the shear bond strength, but the effect of metal primers (V-primer and Metaltite) was not significant and there was disordinal interaction. Significance Metal primers are not always effective for bonding between Y-TZP ceramics and Resin cements. Even though a metal primer is not enough to be used alone, combined application with sandblasting seems to be an appropriate pretreatment for improving the bond strength of Resin cement to Y-TZP ceramics, especially in Panavia F 2.0.
Myung-jae Song - One of the best experts on this subject based on the ideXlab platform.
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Waste minimization pretreatment via pyrolysis and oxidative pyroylsis of organic ion exchange Resin
Waste Management, 1998Co-Authors: Ung-kyung Chun, Kyung-hwa Yang, Jong-kil Park, Kwansik Choi, Myung-jae SongAbstract:Abstract Pyrolysis and/or oxidative pyrolysis of organic ion exchange Resins and other combustible waste may be effective pretreatment processes before vitrification. To further examine these processes, organic ion exchange Resins were pyrolyzed or oxidatively pyrolyzed with the use of a small-scale, commercial TGA. Volatilization of the anionic and cationic Resins was observed separately for each Resin as a function of temperature for pyrolysis and oxidative pyrolysis conditions. The quantity of remains or residue was found to be dependent on the method employed. Three different methods were examined with the TGA to pretreat the Resins: pyrolysis; oxidative pyrolysis; and oxidative pyrolysis of ash remaining after the pyrolysis of Resin. The latter two methods were found to provide better volume reduction than the pyrolysis-only process. Between the two types of Resins, cationic and anionic, the cationic exchange Resin was less volatile. Pyrolysis and oxidative pyrolysis of Mixed Resin (50% cation and 50% anion by wt.) showed volatilization at the temperatures where volatilization was observed for each of the separate Resins. Because of certain limitations of the commercial TGA, tube furnace experiments were performed, generally, to examine the pyrolysis of larger quantities of cationic, anionic, and Mixed Resin, and to examine off-gas characteristics. The cationic Resin-only and anionic Resin-only gravimetric results showed good agreement with the smaller-scale TGA results. SEM pictures of the different variants of the Resin (cationic, anionic, and Mixed) show a different morphology for each. Off-gas data showed the presence of H 2 S, SO 2 , CO, and NO during the pyrolysis of cationic Resin. CO was observed during the pyrolysis of anionic Resin. The Mixed Resin trials showed the presence of the gases approximately at the temperatures where the gases would evolve if the results of the two different Resins (cationic and anionic) were superimposed. However, the amount of hydrogen sulfide relative to the sulfur dioxide was found to increase significantly compared to the results of the cationic Resin-only trials.
Daniel Rolph Schneider - One of the best experts on this subject based on the ideXlab platform.
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Catalytic pyrolysis and kinetic study of real-world waste plastics: multi-layered and Mixed Resin types of plastics
Clean Technologies and Environmental Policy, 2021Co-Authors: Irma Kremer, Tihomir Tomić, Zvonimir Katančić, Matko Erceg, Saša Papuga, Jelena Parlov Vuković, Daniel Rolph SchneiderAbstract:Multi-layered and Mixed Resin types of plastics are a great challenge for the waste recycling industry. The majority consist of two or more types of polymers, making it difficult to recycle mechanically, which leads to landfill or incineration plant. As a way of thermochemical recycling, pyrolysis is a promising cleaner technology that could use this plastics waste stream potential and convert it into valuable products like fuels. The hypotheses of this research are that the average apparent activation energy of multi-layered and Mixed Resin plastic real-world waste samples can be decreased with the addition of selected iron-modified zeolite catalyst and that catalytic pyrolysis in fixed bed reactor will give products that show good potential for use as an energy vector. To evaluate activation energy, kinetic analysis was conducted using the isoconversional model-free Friedman model in conjunction with the multivariate nonlinear regression method. Pyrolysis products were analysed using nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy and calorimetry. The catalyst significantly reduced the activation energy of the flexible plastic film sample, which means that the process with catalyst requires less energy consumption. In the case of rigid plastics, the activation energy was lower at the beginning of the process with the catalyst. The catalyst reduced pyrolytic condensates’ viscosity of both samples. Analyses revealed how catalyst promoted the formation of aliphatic compounds in flexible plastics film oil, monoaromatic compounds in rigid plastics oil, and a significant decrease in polyaromatic compounds that degrade the quality of the fuel. The values of higher heating value were high (36–42 MJ/kg). Finally, the pyrolytic oil composition revealed satisfying quality and good potential for further use as an energy vector due to the high higher heating value. Graphic abstract
Jianlong Wang - One of the best experts on this subject based on the ideXlab platform.
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Mixed Resin and carbon fibres surface treatment for preparation of carbon fibres composites with good interfacial bonding strength
Materials & Design, 2010Co-Authors: Jianlong Wang, Jian WangAbstract:Abstract The objective of this work is to improve the interlaminar shear strength of composites by mixing epoxy Resin and modifying carbon fibres. The effect of Mixed Resin matrix’s structure on carbon fibres composites was studied. Anodic oxidation treatment was used to modify the surface of carbon fibres. The tensile strength of multifilament and interlaminar shear strength of composites were investigated respectively. The morphologies of untreated and treated carbon fibres were characterized by scanning electron microscope and X-ray photoelectron spectroscopy. Surface analysis indicates that the amount of carbon fibres chemisorbed oxygen-containing groups, active carbon atom, the surface roughness, and wetting ability increases after treatment. The tensile strength of carbon fibres decreased little after treatment by anodic oxidation. The results show that the treated carbon fibres composites could possess excellent interfacial properties with Mixed Resins, and interlaminar shear strength of the composites is up to 85.41 MPa. The mechanism of Mixed Resins and treated carbon fibres to improve the interfacial property of composites is obtained.