The melting/crystallization properties of blends obtained by mixing two isotactic polypropylene (iPP) samples synthesized using single-site metallocene catalyst systems and containing a high and low concentration of rr triads as stereo-defects, are studied. The changes occurring at lamellar length scale during a heating/cooling cycles at constant scanning rate are followed in situ by performing time-resolved small angle X-ray scattering (SAXS) measurements. Data analysis demonstrates that the evolution of the SAXS intensity with increase/decrease of the temperature is controlled by the separate melting/crystallization of the two components, the differences in the thermal expansion (contraction) coefficient of the amorphous and crystalline phases and the role of thermal fluctuations in electron density. The two components give rise to different populations of intermixed lamellar stacks in the blends which originate from the good miscibility of the low and high stereoregular samples in the melt.

通过混合使用单中心茂金属催化剂系统合成的两个全同立构聚丙烯（iPP）样品而获得的共混物的熔融/结晶性能，其中高和低浓度的rr对三元组作为立体缺陷进行了研究。通过执行时间分辨的小角度X射线散射（SAXS）测量，就地跟踪在恒定扫描速率下的加热/冷却循环期间在层状长度尺度上发生的变化。数据分析表明，随着温度的升高/降低，SAXS强度的演变受两种组分的单独熔融/结晶，非晶相和结晶相的热膨胀（收缩）系数的差异以及三元醇的作用控制。电子密度的热波动。这两种组分在共混物中产生了不同的混合层状堆叠体，这是由于低和高立构规整样品在熔体中的良好混溶性引起的。