【摘要】 基于自由体积理论,利用正电子湮灭寿命谱仪(PALS)分别研究在不同升温速率条件下,聚苯乙烯-甲基丙烯酸甲酯共聚物(SMMA)和聚苯乙烯-马来酸酐共聚物(SMA)混合物(30/70)的自由体积参数的温度依赖性,探索相容共混物相行为的热动态特性.在PALS实验中,在玻璃化转变温度Tg以上,当结构松弛的弛豫时间与等温停留时间相当,发现在某一段温度范围内,共混物的自由体积参数随着温度的变化明显地偏离线性关系.从自由体积孔的浓度I3值在该段的变化趋势,初步推断共混物在该温度段经历了相分离的成长阶段.更多还原

【Abstract】 The temperature dependence of the free volume in SMMA/SMA （30/70） blend was investigated by the positron annihilation life spectroscopy （PALS） at different heating rates according to the free volume theory, and the thermodynamics characteristics of the phase behavior of the polymer blends was also explored. At temperatures above T_g, we found from the positron annihilation life spectra that when the structural relaxation time is comparable with the retention time, the temperature dependence of the free volume parameters obviously departs from the linear relation. Based upon the change tendency of the free volume concentration I₃ with temperature, it is postulated that there is a growing stage of the phase separation in the same temperature range.更多还原