Silane coupling agent KH560 was used to modify the surface of nano-α-Al<sub>2</sub>O<sub>3</sub> in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al<sub&...Silane coupling agent KH560 was used to modify the surface of nano-α-Al<sub>2</sub>O<sub>3</sub> in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> was determined by nano-particle size analyzer, and the effects of nano-α-Al<sub>2</sub>O<sub>3</sub> content, ethanol-aqueous solution ratio and KH560 dosage on the dispersion and particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> were investigated. The material structure before and after modification was determined by Fourier transform infrared spectroscopy (FTIR). Aqueous polyurethane resin and inorganic components are combined with modified nano-α-Al<sub>2</sub>O<sub>3</sub> dispersion to form chromium-free passivation solution. The solution is coated on the galvanized sheet, the adhesion and surface hardness are tested, the bonding strength of the coating and the surface hardness of the substrate are discussed. The corrosion resistance and surface morphology of the matrix were investigated by electrochemical test, neutral salt spray test and scanning electron microscope test. The chromium-free passivation film formed after the modification of nano-α-Al<sub>2</sub>O<sub>3</sub> increases the surface hardness of galvanized sheet by about 85%. The corrosion resistance of the film is better than that of a single polyurethane film. The results show that the surface hardness and corrosion resistance of polyurethane resin composite passivation film are significantly improved by the introduction of nano-α-Al<sub>2</sub>O<sub>3</sub>.展开更多
Purpose: The mechanical strength of polymethyl methacrylate (PMMA) remains far from ideal for maintaining the longevity of denture. The purpose of this study was to evaluate the effect of Zirconium oxide (ZrO2) nanofi...Purpose: The mechanical strength of polymethyl methacrylate (PMMA) remains far from ideal for maintaining the longevity of denture. The purpose of this study was to evaluate the effect of Zirconium oxide (ZrO2) nanofillers powder with different concentration (1.5%, 3%, 5% and 7%) on the flexural strength, fracture toughness, and hardness of heat-polymerized acrylic resin. Materials and methods: Zirconium oxide powders with different concentrations (1.5%, 3%, 5% and 7%) were incorporated into heat-cure acrylic resin (PMMA) and processed with optimal condition (2.5:1 Powder/monomer ratio, conventional packing method and water bath curing for 2 hours at 95。C) to fabricate test specimens of PMMA of dimensions (50 × 30 × 30 mm) for the flexural strength, fracture toughness, and (50 × 30 × 30 mm) were fabricated for measuring hardness. PMMA without additives was prepared as a test control. Three types of mechanical tests;flexural strength, fracture toughness and hardness were carried out on the samples. The recorded values of flexural strength in (MPa), fracture toughness in (MPa.m1/2), and hardness (VHN) were collected, tabulated and statistically analyzed. One way analysis of variance (ANOVA) and Tukey’s tests were used for testing the significance between the means of tested groups which are statistically significant when the P value ≤ 0.05. Results: Addition of Zirconium oxide nanofillers to PMMA significantly increased the flexural strength, fracture toughness and hardness. Conclusion: These results indicate that Zirconium oxide nanofillers added to PMMA has a potential as a reliable denture base material with increased flexural strength, fracture toughness, and hardness. According to the results of the present study, the best mechanical properties were achieved by adding 7%wt ZrO2 concentration.展开更多
用苯甲醛对双氰胺进行改性，制备了一种新型改性双氰胺固化剂。对合成条件进行了优化，并对其固化条件进行了研究。结果表明，苯甲醛改性双氰胺的较佳工艺条件为pH值3~4，苯甲醛与双氰胺物质的量比为1∶1.5，于95℃，反应2 h，收率65.67...用苯甲醛对双氰胺进行改性，制备了一种新型改性双氰胺固化剂。对合成条件进行了优化，并对其固化条件进行了研究。结果表明，苯甲醛改性双氰胺的较佳工艺条件为pH值3~4，苯甲醛与双氰胺物质的量比为1∶1.5，于95℃，反应2 h，收率65.67%。通过测试涂层硬度来考察固化工艺与性能。作为环氧树脂固化剂单独使用时，与环氧树脂的质量比为1∶10，固化温度为130℃固化8 h 涂膜硬度HV1=47.52。比双氰胺体系固化温度（160℃）降低了30℃。展开更多
背景:与传统复合树脂材料相比,大块充填复合树脂材料具有增加光固化深度、降低聚合收缩率、简化临床操作程序等特点,但不同类型大块充填复合树脂材料的性能各异。目的:分析4种复合树脂材料的硬度及黏结强度。方法:取大块填充复合树脂Tet...背景:与传统复合树脂材料相比,大块充填复合树脂材料具有增加光固化深度、降低聚合收缩率、简化临床操作程序等特点,但不同类型大块充填复合树脂材料的性能各异。目的:分析4种复合树脂材料的硬度及黏结强度。方法:取大块填充复合树脂Tetric Evo Ceram Bulk Fill、SDR,以及传统复合树脂P60、Z350,检测4种复合树脂材料分别在2,3,4,5 mm光固化深度下的维氏显微硬度,以及4种复合树脂材料与牙本质间的剪切黏结强度。结果与结论:不同光固化深度下的硬度顺序为:P60复合树脂>Z350复合树脂>Tetric Evo Ceram Bulk Fill复合树脂>SDR复合树脂,4组间比较差异有显著性意义(P<0.05);Tetric Evo Ceram Bulk Filll和SDR复合树脂光固化后的硬度未随着固化深度的增加而明显减小。Tetric Evo Cream Bulk Fil和SDR复合树脂的剪切黏结强度显著高于P60和Z350复合树脂(P<0.05)。表明大块充填树脂材料Tetric Evo Ceram Bulk Fill和SDR的综合机械性能较高,并且具有较高的剪切黏结强度。展开更多
文摘Silane coupling agent KH560 was used to modify the surface of nano-α-Al<sub>2</sub>O<sub>3</sub> in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> was determined by nano-particle size analyzer, and the effects of nano-α-Al<sub>2</sub>O<sub>3</sub> content, ethanol-aqueous solution ratio and KH560 dosage on the dispersion and particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> were investigated. The material structure before and after modification was determined by Fourier transform infrared spectroscopy (FTIR). Aqueous polyurethane resin and inorganic components are combined with modified nano-α-Al<sub>2</sub>O<sub>3</sub> dispersion to form chromium-free passivation solution. The solution is coated on the galvanized sheet, the adhesion and surface hardness are tested, the bonding strength of the coating and the surface hardness of the substrate are discussed. The corrosion resistance and surface morphology of the matrix were investigated by electrochemical test, neutral salt spray test and scanning electron microscope test. The chromium-free passivation film formed after the modification of nano-α-Al<sub>2</sub>O<sub>3</sub> increases the surface hardness of galvanized sheet by about 85%. The corrosion resistance of the film is better than that of a single polyurethane film. The results show that the surface hardness and corrosion resistance of polyurethane resin composite passivation film are significantly improved by the introduction of nano-α-Al<sub>2</sub>O<sub>3</sub>.
文摘Purpose: The mechanical strength of polymethyl methacrylate (PMMA) remains far from ideal for maintaining the longevity of denture. The purpose of this study was to evaluate the effect of Zirconium oxide (ZrO2) nanofillers powder with different concentration (1.5%, 3%, 5% and 7%) on the flexural strength, fracture toughness, and hardness of heat-polymerized acrylic resin. Materials and methods: Zirconium oxide powders with different concentrations (1.5%, 3%, 5% and 7%) were incorporated into heat-cure acrylic resin (PMMA) and processed with optimal condition (2.5:1 Powder/monomer ratio, conventional packing method and water bath curing for 2 hours at 95。C) to fabricate test specimens of PMMA of dimensions (50 × 30 × 30 mm) for the flexural strength, fracture toughness, and (50 × 30 × 30 mm) were fabricated for measuring hardness. PMMA without additives was prepared as a test control. Three types of mechanical tests;flexural strength, fracture toughness and hardness were carried out on the samples. The recorded values of flexural strength in (MPa), fracture toughness in (MPa.m1/2), and hardness (VHN) were collected, tabulated and statistically analyzed. One way analysis of variance (ANOVA) and Tukey’s tests were used for testing the significance between the means of tested groups which are statistically significant when the P value ≤ 0.05. Results: Addition of Zirconium oxide nanofillers to PMMA significantly increased the flexural strength, fracture toughness and hardness. Conclusion: These results indicate that Zirconium oxide nanofillers added to PMMA has a potential as a reliable denture base material with increased flexural strength, fracture toughness, and hardness. According to the results of the present study, the best mechanical properties were achieved by adding 7%wt ZrO2 concentration.
文摘用苯甲醛对双氰胺进行改性，制备了一种新型改性双氰胺固化剂。对合成条件进行了优化，并对其固化条件进行了研究。结果表明，苯甲醛改性双氰胺的较佳工艺条件为pH值3~4，苯甲醛与双氰胺物质的量比为1∶1.5，于95℃，反应2 h，收率65.67%。通过测试涂层硬度来考察固化工艺与性能。作为环氧树脂固化剂单独使用时，与环氧树脂的质量比为1∶10，固化温度为130℃固化8 h 涂膜硬度HV1=47.52。比双氰胺体系固化温度（160℃）降低了30℃。
文摘背景:与传统复合树脂材料相比,大块充填复合树脂材料具有增加光固化深度、降低聚合收缩率、简化临床操作程序等特点,但不同类型大块充填复合树脂材料的性能各异。目的:分析4种复合树脂材料的硬度及黏结强度。方法:取大块填充复合树脂Tetric Evo Ceram Bulk Fill、SDR,以及传统复合树脂P60、Z350,检测4种复合树脂材料分别在2,3,4,5 mm光固化深度下的维氏显微硬度,以及4种复合树脂材料与牙本质间的剪切黏结强度。结果与结论:不同光固化深度下的硬度顺序为:P60复合树脂>Z350复合树脂>Tetric Evo Ceram Bulk Fill复合树脂>SDR复合树脂,4组间比较差异有显著性意义(P<0.05);Tetric Evo Ceram Bulk Filll和SDR复合树脂光固化后的硬度未随着固化深度的增加而明显减小。Tetric Evo Cream Bulk Fil和SDR复合树脂的剪切黏结强度显著高于P60和Z350复合树脂(P<0.05)。表明大块充填树脂材料Tetric Evo Ceram Bulk Fill和SDR的综合机械性能较高,并且具有较高的剪切黏结强度。
