Konishi Takashi, Okamoto Daisuke, Tadokoro Daisuke, Kawahara Yoshitaka, Fukao Koji, Miyamoto Yoshihisa
Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan.
Department of Physics, Ritsumeikan University, Noji-Higashi 1-1-1, Kusatsu 525-8577, Japan.
Phys Rev Lett. 2022 Mar 11;128(10):107801. doi: 10.1103/PhysRevLett.128.107801.
The isothermal crystallization near the glass transition temperature from the melt state of poly(trimethylene terephthalate) has been studied by wide-angle x-ray diffraction (WAXD), small-angle x-ray scattering (SAXS), and optical microscopy. The SAXS and WAXD results show the crystallization mechanism in which the crystalline nodules cover the entire sample with the formation of aggregation regions. The analysis of the SAXS results using Kolmogorov-Johnson-Mehl-Avrami theory indicates that the formation kinetics of the aggregation regions is of three-dimensional homogeneous nucleation type. The analysis of the SAXS profiles using Sekimoto's theory provides the growth velocity and the nucleation rate of the aggregation region. The temperature dependence of the growth velocity of the aggregation region is a natural extrapolation of that of spherulite to the high supercooling region. The temperature dependence of the nucleation rate of the aggregation region is also represented by the parameters of the spherulitic growth rate. The result of the growth velocities of the aggregation region and the spherulite suggests the existence of precursors at the front of the crystal growth.
利用广角X射线衍射（WAXD）、小角X射线散射（SAXS）和光学显微镜研究了聚对苯二甲酸丙二醇酯从熔融态在玻璃化转变温度附近的等温结晶过程。SAXS和WAXD结果表明了结晶机制，即结晶结节通过聚集区域的形成覆盖整个样品。使用Kolmogorov-Johnson-Mehl-Avrami理论对SAXS结果进行分析表明，聚集区域的形成动力学属于三维均相成核类型。使用Sekimoto理论对SAXS谱进行分析，得到了聚集区域的生长速度和成核速率。聚集区域生长速度的温度依赖性是球晶生长速度温度依赖性向高过冷区域的自然外推。聚集区域成核速率的温度依赖性也由球晶生长速率的参数表示。聚集区域和球晶生长速度的结果表明在晶体生长前沿存在前驱体。
