Sugeno Kousuke, Saito Hiromu
Department of Organic and Polymer Materials Chemistry, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184-8588, Japan.
Polymers (Basel). 2024 Nov 29;16(23):3357. doi: 10.3390/polym16233357.
We investigated the crystallization kinetics and morphology evolution of miscible crystalline/crystalline blends of poly(trimethylene terephthalate) (PTT) and poly(ethylene terephthalate) (PET) during isothermal melt crystallization. The integrated light-scattering intensity and the spherulite size increased gradually and then steeply as crystallization progressed in 70/30 PTT/PET at 215 °C, indicating the two-step crystallization behavior. The compact PET spherulite grew in the first step, and the dendritic PTT spherulite grew in the second step, forming the double spherulite consisting of a PET component in the inner region and a PTT one in the outer region. The spherulite size of PET increased nonlinearly with time, suggesting the exclusion of PTT from the crystal growth front. Atomic force microscopy (AFM) observation revealed that the PTT fibrils were interfiled within the PET spherulite in the inner region and continued outward to the outer region consisting of the PTT spherulite. These results suggest that the excluded PTT crystallizes into fibrils by interfiling crystallization within the inner PET spherulite, and then the interfiled PTT fibrils continue to grow outward to form the outer dendritic PTT spherulite after the spherulite growth of PET stops due to the excluded PTT at the growth front.
我们研究了聚对苯二甲酸丙二醇酯（PTT）和聚对苯二甲酸乙二酯（PET）的可混溶结晶/结晶共混物在等温熔体结晶过程中的结晶动力学和形态演变。在215°C下，随着70/30 PTT/PET结晶过程的进行，积分光散射强度和球晶尺寸先逐渐增加，然后急剧增加，表明存在两步结晶行为。致密的PET球晶在第一步生长，树枝状的PTT球晶在第二步生长，形成了由内部区域的PET组分和外部区域的PTT组分组成的双球晶。PET的球晶尺寸随时间呈非线性增加，这表明PTT被排除在晶体生长前沿之外。原子力显微镜（AFM）观察表明，PTT原纤维在内部区域的PET球晶内相互交织，并向外延伸至由PTT球晶组成的外部区域。这些结果表明，被排除的PTT通过在内部PET球晶内的相互交织结晶形成原纤维，然后在PET球晶生长因生长前沿的PTT被排除而停止后，相互交织的PTT原纤维继续向外生长，形成外部树枝状PTT球晶。
