Stability Limits of Pressure Densified Polycarbonate Glass
Stability Limits of Pressure Densified Polycarbonate Glass
复制标题
压力致密聚碳酸酯玻璃的稳定性极限
作者：
A. Holt;D. Fragiadakis;J. Wollmershauser;B. Feigelson;M. Tyagi;C. Roland
高压下形成的聚碳酸酯（PC）玻璃的物理性能进行了实验评估和比较的一个简单的模型聚合物能够压力致密化的分子动力学模拟。压力致密化玻璃（PDG）表现出更高的焓，并且比在环境压力下形成的相应玻璃密度高4%。第一个尖锐的衍射峰的测量表明，局部密度波动被抑制在PDG，证实了弹性非相干中子散射测量。实验和模拟结果均表明，PDG的稳定性降低限制了压力致密化有效的压力;在过高的压力下，玻璃化转变温度福尔斯低于环境温度。
The physical properties of a polycarbonate (PC) glass formed under high pressure are evaluated experimentally and compared to molecular dynamics simulations of a simple model polymer capable of pressure densification. Pressure densified glass (PDG) exhibits higher enthalpy and is as much as 4% denser than the corresponding glass formed at ambient pressure. Measurements of the first sharp diffraction peak reveal that local density fluctuations are suppressed in PDG, as corroborated by elastic incoherent neutron scattering measurements. Both the experimental and simulation results indicate that the reduced stability of PDG limits the pressures for which pressure densification is effective; at too high a pressure the glass transition temperature falls below ambient.