STUDY ON STRESS INDUCED CORROSION AND LIFETIME OF DENTAL RESIN

牙科树脂的应力腐蚀和寿命研究

• 批准号: 14571872
• 负责人: GOTO Takayasu
• 金额: $ 2.24万
• 依托单位: ASAHI UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14571872/
• 关键词: Heat cured denture base resin; Environmental stress cracking; Environmental solution; Fracture toughness; Stess intensity factor; Crack growth velocity; 加熱重合レジン; 床の割れ; クレーズ; 溶解反応; 架橋材; 加熱重合アクリルレジン; 割れのメカニズム; 機械化学的反応; 非線形破壊

The mechanism of cracking in heat-cured denture base resin was investigated with a view of environmental stress cracking (ESC), by the measurement of fracture toughness (K_<IC>), the analysis of non-linear fracture energy, the measurement of crack growth velocity (V) and the stress intensity factor (K_I), and the observation of fracture surface. Although the K_<IC> depends on the water and the strain rate, the most appropriate value of the specimen with absorbed water was estimated to be about 1.0 MPa. m^<1/2> when the slow crack growth (SCG) never occurred. From the application of the dimensionless load-load point displacement curve, it was found that the plastic energy dissipation rate was greater than the net energy required for the formation of the crack surface. The V of both specimens without and with absorbed water in denture base resins increased with increasing K_I in both ethanol and acetic acid solution, and converged on about 1 μm/s when K_I approached K_<IC>. In case of higher concentration, V converged on the same value even when K_I was small. The V of industrial resin with absorbed water behaved much like denture base resins, but increased without convergence in dried specimen. This was attributed that the water prevented the environmental solutions from diffusing. Furthermore, the fracture surface of any resins with absorbed water showed the striped pattern, but without water the smooth surface appeared at heigh concentration. From these results, it is suggested that the ESC in denture base resin would occur and is considered the follwing mechanisms. (1)The cracking is caused by the dissolution of polymer chain under the presence of both stress and environmental solution, and/or (2)by the rupture of primary polymer chain dur to the direct reaction between chain and environmental solution.

从环境应力开裂（ESC）的角度，通过断裂韧性（K）的测定<IC>、非线性断裂能分析、裂纹扩展速度（V）和应力强度因子（KI）的测定以及断口形貌观察，探讨了热固化义齿基托树脂的开裂机理。虽然K值<IC>与水含量和应变速率有关，但对吸水试样的K值最合适，约为1.0MPa。m^&lt;1/2&gt;，此时未发生缓慢裂纹扩展（SCG）。由无量纲荷载-荷载点位移曲线的应用发现，塑性能量耗散率大于裂纹面形成所需的净能量。在乙醇和醋酸溶液中，基托树脂吸水前后的V值均随KI的增大而增大，当KI接近KI时，V值趋于1 μm/s<IC>。在较高浓度下，即使KI较小时，V也收敛于同一值。工业树脂吸水后的V值与义齿基托树脂相似，但在干燥后无收敛现象。这是由于水阻止了环境溶液的扩散。吸水后的树脂在高浓度时断面呈条纹状，而不吸水时断面光滑。结果表明，义齿基托树脂中存在ESC，并认为其机制为：（1）在应力和环境溶液的共同作用下，聚合物链发生溶解;（2）聚合物链与环境溶液直接反应，聚合物主链断裂。

项目成果

K.Paku, T.Goto, et al.: "Influences of strain rate and water on fracture toughness of heat cured denture base acrylic resin"J.Gifu Dent.Soc.. 29(3). 173-179 (2003)

K.Paku、T.Goto 等：“应变率和水对热固化义齿基托丙烯酸树脂断裂韧性的影响”J.Gifu Dent.Soc. 29(3)。

Takayasu Goto, Kenji Paku et al.: "Application of the dimensionless load-load point displacement curve to analyze the non-linear fracture parameters of dental resin"J.Gifu Dent.Soc.. 29(3)(in press). (2003)

Takayasu Goto、Kenji Paku 等：“应用无量纲载荷-载荷点位移曲线分析牙科树脂的非线性断裂参数”J.Gifu Dent.Soc.. 29(3)（印刷中）。

T.Goto, K.Paku, et al.: "Application of the dimensionless load-load point displacement curve to analyze the non-linear fracture parameters of dental resin"J.Gifu Dent.Soc.. 29(3). 180-185 (2003)

T.Goto，K.Paku，等：“应用无量纲载荷-载荷点位移曲线分析牙科树脂的非线性断裂参数”J.Gifu Dent.Soc.. 29(3)。

H.Higashino, M.Yamauchi, T.Goto, T.Nagasawa: "Evaluation of brittleness of porcelain fused to pure titanium by fracture toughness, hardness and fracture energy"Dent.Mater.J.. 22(4). 532-542 (2003)

H.Higashino、M.Yamauchi、T.Goto、T.Nagasawa：“通过断裂韧性、硬度和断裂能评价纯钛熔瓷的脆性”Dent.Mater.J.. 22(4)。

H.Higashino, M.Yamauchi, T.Goto, T.Nagasawa: "Evaluation of brittleness of porcelain fused to pure titanium by fracture toughness, hardness and fracture energy"Dent. Mater. J.. 22(4). 532-542 (2003)

H.Higashino、M.Yamauchi、T.Goto、T.Nagasawa：“通过断裂韧性、硬度和断裂能评价纯钛熔瓷的脆性”Dent。