Morphology and domain sizes in isotactic polybutene-1 homopolymer (iPB-1) and (butene-1)-ethylene random copolymer (iPB-1/C2) are studied by spin-diffusion time-domain ¹H NMR and SAXS experiments. Lamellar thickness is smaller for iPB-1/C2 than for iPB-1 and decreases with decreasing crystallization temperature. iPB-1/C2 with form I’ crystals, which were directly formed upon crystallization from a heterogeneous melt, has typical for polyolefins lamellar morphology with the crystal-amorphous interface that separates crystal lamellae and interlamellar amorphous domains. Different lamellar structure is observed in iPB-1 and iPB-1/C2 with form I crystals which were obtained upon polymorphic phase transition from form II to form I crystals. The phase transition causes fragmentation of crystal lamellae into small blocks with a wide size distribution as was shown by the NMR method. Two types of the interface are present in these samples: the inner interface that separates crystal blocks within fragmented crystal lamellae, and the crystal-amorphous interface on the surface of fragmented lamellae. The molecular mechanism of polymorphic form II to form I phase transition is proposed. High chain mobility in form II crystals and chain folding structure on the lamellar surface play significant role at the initial and final stages of the restructuring of crystal lamellae during the phase transition, respectively.

通过自旋扩散时域¹研究了全同立构聚丁烯-1均聚物（iPB-1）和（丁烯-1）-乙烯无规共聚物（iPB-1 / C2）的形貌和畴尺寸1 H NMR和SAXS实验。iPB-1 / C2的层状厚度小于iPB-1的层状厚度，并且随着结晶温度的降低而减小。从异质熔体中结晶后直接形成的具有I'型晶体的iPB-1 / C2具有典型的聚烯烃层状形态，其晶体-非晶界面将晶体层和层间非晶域分开。在具有形式I晶体的iPB-1和iPB-1 / C2中观察到了不同的层状结构，这些晶体是通过从形式II到形式I的多晶相转变获得的。如NMR方法所示，相变导致晶体薄片破碎成具有宽尺寸分布的小块。这些示例中存在两种类型的接口：内部的界面将碎裂的晶体薄片内的晶体块分开，而碎裂的薄片表面上的晶体-非晶界面。提出了II型多晶型形成I相变的分子机理。II型晶体的高链迁移率和层状表面上的链折叠结构分别在相变过程中晶体薄片重组的初始阶段和最终阶段起着重要作用。