Atomic and vibrational origins of mechanical toughness in bioactive cement during setting.
Atomic and vibrational origins of mechanical toughness in bioactive cement during setting.
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DOI：
10.1038/ncomms9631
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发表时间：
2015-11-09
影响因子：
16.6
通讯作者：
Greaves GN
中科院分区：
文献类型：
--
作者：
Tian KV;Yang B;Yue Y;Bowron DT;Mayers J;Donnan RS;Dobó-Nagy C;Nicholson JW;Fang DC;Greer AL;Chass GA;Greaves GN
生物活性玻璃离子水门汀（GIC）已在牙科和医学领域广泛使用了近40年。然而，这些复合材料达不到永久性植入物所需的韧性。改进的重大障碍是必须使用传统的破坏性机械测试，这必然是回顾性的。在这里，我们定量地显示，通过新的使用量热法，太赫兹（THz）光谱和中子散射，如何GIC的发展断裂韧性在设置过程中与界面太赫兹动力学，改变原子凝聚力和波动的界面配置。与常规相反，我们发现设置是非单调的，其特征在于，以前没有检测到的突然的功能，包括玻璃-聚合物耦合点，早期的设置点，其中降低的韧性意外恢复，随后由应力引起的界面弱化。随后，韧性逐渐下降到长期断裂试验值。我们期望这些原位非破坏性技术所提供的洞察力将有助于提高对胶凝材料的凝固机制和相关动力学的理解。 生物活性粘固剂广泛用于牙科和医学。在这里，使用各种新的实验技术，作者揭示了原子和振动的贡献，在凝固过程中的生物活性水泥的机械韧性。
Bioactive glass ionomer cements (GICs) have been in widespread use for ∼40 years in dentistry and medicine. However, these composites fall short of the toughness needed for permanent implants. Significant impediment to improvement has been the requisite use of conventional destructive mechanical testing, which is necessarily retrospective. Here we show quantitatively, through the novel use of calorimetry, terahertz (THz) spectroscopy and neutron scattering, how GIC's developing fracture toughness during setting is related to interfacial THz dynamics, changing atomic cohesion and fluctuating interfacial configurations. Contrary to convention, we find setting is non-monotonic, characterized by abrupt features not previously detected, including a glass–polymer coupling point, an early setting point, where decreasing toughness unexpectedly recovers, followed by stress-induced weakening of interfaces. Subsequently, toughness declines asymptotically to long-term fracture test values. We expect the insight afforded by these in situ non-destructive techniques will assist in raising understanding of the setting mechanisms and associated dynamics of cementitious materials. Bioactive cements are widely used in dentistry and medicine. Here, using a variety of novel experimental techniques, the authors uncover the atomic and vibrational contributions to the mechanical toughness of bioactive cement during the setting process.