Study on Toughening of composite resins using fatigue crack propagation test

复合树脂增韧疲劳裂纹扩展试验研究

• 批准号: 07457455
• 负责人: TAKESHIGE Fumio
• 金额: $ 0.26万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07457455/
• 关键词: Composite resin; Fatigue strength; Fatigue crack; Filler; Toughening; 高靱化

The equation, da/dN=C (DELTAK) ^m, could be applied to the fatigue crack propagation of the composites both in the atmosphere and in the water environment. The DELTAK_<th> for composite resins in the atmosphere was in the range of 0.43-0.82MPa・m^<1/2>, and that in the water increased to the range of 0.52-1.12Mpa・m^<1/2.> The expansion of matrix due to the water absorption enhanced the fatigue resistance of composites. The residual compression stress in the matrix might arrest the fatigue crack.The fatigue crack of dental composites propagated mostly along the interface between inorganic filler and matrix. In the contrast to inorganic filler, some organic fillers were penetrated with fatigue cracks. The crack was bridged, bowed or deflected by the inoganic filler, and consequently the energy release rate for crack propagation was increased. These showed that crack deflection and crack bridging by inorganic filler increased the fatigue resistance of composites. The inorganic filler larger than 10mum was effective in arresting the fatigue crack propagation. The aspect ratio and the size of inorganic filler in composites might be influential factors for their fatigue resistance.There was no significant reduction of bending strength after 3m aging in water. On the contrary, the fatigue resistance measured as DELTAK_<th> was decreased by aging for only 1m. Fatigue crack growth rate was more sensitive to degradation of composites by aging in water than bending strength.Thus, it can be concluded that the crack deflection and the crack bridging by inorganic filler increase the fatigue resistance of composites, and the expansions of matrix due to the water absorption enhance the fatigue resistance of composites. From the present study, it was shown that the fatigue crack propagation test was an effective method to investigate toughening and degradation of dental composites.

方程 da/dN=C (DELTAK) ^m 可应用于大气和水环境中复合材料的疲劳裂纹扩展。复合树脂在大气中的DELTAK_<th>范围为0.43-0.82MPa·m^<1/2>，在水中则增加到0.52-1.12Mpa·m^<1/2>。基体吸水膨胀，增强了复合材料的抗疲劳性能。基体中的残余压应力可以阻止疲劳裂纹的产生。牙科复合材料的疲劳裂纹主要沿着无机填料与基体的界面扩展。与无机填料相反，一些有机填料出现疲劳裂纹。无机填料使裂纹桥接、弯曲或偏转，从而增加了裂纹扩展的能量释放速率。这些表明无机填料的裂纹偏转和裂纹桥接提高了复合材料的抗疲劳性。大于10μm的无机填料能有效阻止疲劳裂纹的扩展。复合材料中无机填料的长径比和尺寸可能是其抗疲劳性能的影响因素。水中老化3m后弯曲强度没有明显下降。相反，以DELTAK_<th>测量的抗疲劳性仅老化1m就降低了。与弯曲强度相比，疲劳裂纹扩展速率对水中老化引起的复合材料退化更为敏感。因此，可以得出结论，裂纹偏转和无机填料的裂纹桥接提高了复合材料的抗疲劳性能，而吸水引起的基体膨胀增强了复合材料的抗疲劳性能。目前的研究表明，疲劳裂纹扩展试验是研究牙科复合材料增韧和降解的有效方法。

项目成果

F. Takeshige et al.: "Fatigue Crack Propagation of Composites Resins in Water Environment." Journal of Dental Research. vol76, Special Issue. 77 (1997)

F. Takeshige 等人：“水环境中复合树脂的疲劳裂纹扩展”。