Macroscopic pressure–volume–temperature properties versus free-volume characteristics of isotropic pressure-densified amorphous polymer glasses
Macroscopic pressure–volume–temperature properties versus free-volume characteristics of isotropic pressure-densified amorphous polymer glasses
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DOI：
10.1063/1.481748
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发表时间：
2000-06
影响因子：
4.4
通讯作者：
M. Schmidt;M. Olsson;F. Maurer
中科院分区：
文献类型：
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作者：
M. Schmidt;M. Olsson;F. Maurer
我们做了一系列各向同性的压力致密化（0-200 MPa）无定形均聚物[无规聚苯乙烯（a-PS）]和共聚物[聚（苯乙烯-丙烯腈共聚物）（SAN）和聚（苯乙烯-马来酸酐）（SMA）]玻璃，并从Simha-Somcynsky状态方程（EOS）研究了它们的宏观压力-体积-温度（PVT）特性与自由体积特性理论和正电子湮没寿命谱（帕尔斯）。玻璃密度在1.0403-1.0535 g/cm 3（PS）、1.0573-1.0759 g/cm 3（SAN）和1.0989-1.1196 g/cm 3（SMA）的范围内。随着形成压力的增加，所有压力致密化玻璃的体积和自由体积都呈现出减小的特征，比容（1.26%-1.85%）的变化为：<正电子偶素（o-Ps）寿命τ3（5.5%-9.1%）<自由体积孔尺寸V（τ3）（10.3%-17.1%）<自由体积分数h（25.1%-30.5%）。我们发现，此外，o-Ps形成概率I3是独立的地层压力。同样，玻璃的热膨胀系数也...
We made a series of isotropic pressure-densified (0–200 MPa) amorphous homopolymer [atactic polystyrene (a-PS)] and copolymer [poly(styrene-co-acrylonitrile) (SAN) and poly(styreneco-maleic anhydride) (SMA)] glasses and studied their macroscopic pressure–volume–temperature (PVT) properties vs their free-volume characteristics from the Simha–Somcynsky equation-of-state (EOS) theory and from positron annihilation lifetime spectroscopy (PALS). The glass densities lie in the range of 1.0403–1.0535 g/cm3 (PS), 1.0573–1.0759 g/cm3 (SAN), and 1.0989–1.1196 g/cm3 (SMA). With increasing formation pressure, all pressure-densified glasses exhibit decreasing volume and free-volume characteristics such that the changes in specific volume (1.26%–1.85%) are <ortho-positronium (o-Ps) lifetime τ3 (5.5%–9.1%) <free-volume hole size V(τ3) (10.3%–17.1%) <free-volume fraction h (25.1%–30.5%). We find, furthermore, that the o-Ps formation probability I3 is independent of formation pressure. Likewise, the glasses’ thermal expan...