In this work, the formation of cocontinuous structure in immiscible high density polyethylene/isotactic polypropylene (HDPE/iPP) blends was investigated for various olefin-based compatibilizers of distinct molecular architectures, including ternary random copolymer EPDM, olefin block copolymer (OBC), polypropylene-based OBC (PP-OBC), ethylene/a-olefin copolymer (POE), bottlebrush polymer poly(1-dodecene), and comb-like poly(propylene-co-high a-olefin) (PPO). The scanning electron microscopy results show that after adding OBC, PP-OBC, and POE copolymers, the finer droplet-in-matrix morphologies were obtained in 70/30 HDPE/iPP blend. Interestingly, for 70/30 HDPE/iPP blend with just 5 wt% of PPO copolymers, the phase inversion from droplet-in-matrix to cocontinuous morphology can be observed. It was proposed that the development of cocontinuous morphology contained the following steps: (1) interfacial saturation of compatibilizers and droplet deformation, (2) droplet-droplet coalescence, (3) continuity development, and (4) the formation of dual-phase continuity. Among the diverse copolymers studied in this work, PPO copolymer can be easily removed out of the interface during droplet coalescence and stabilize the curvature of minor fiber phase, facilitating the formation of cocontinuous morphology. In contrast, other olefin-based compatibilizers (EPDM, OBC, PP-OBC, and POE) exhibit the distinct steric repulsion effect to prohibit droplet coalescence. Moreover, the cocontinous interval varies with the compatibilizer architectures. Surprisingly, after adding 10 wt% of PPO copolymers, the cocontinuous interval was greatly broadened from HDPE/iPP range of 45/55–60/40 to that of 40/60–70/30.

在这项工作中，研究了不相容的高密度聚乙烯/全同立构聚丙烯（HDPE / iPP）共混物中共连续结构的形成，以研究具有不同分子结构的各种烯烃基相容剂，包括三元无规共聚物EPDM，烯烃嵌段共聚物（OBC），聚丙烯基OBC（PP-OBC），乙烯/一烯烃共聚物（POE），瓶刷聚合物聚（1-十二碳烯），和梳状聚（丙烯-共-高一个-烯烃）（PPO）。扫描电子显微镜结果表明，加入OBC，PP-OBC和POE共聚物后，在70/30 HDPE / iPP共混物中获得了更细的液滴在基质中的形貌。有趣的是，对于仅含有5 wt％的PPO共聚物的70/30 HDPE / iPP共混物，可以观察到从基质滴到共连续形态的相转化。提出共连续形态的发展包括以下步骤：（1）增容剂的界面饱和和液滴变形；（2）液滴与液滴的结合；（3）连续性发展；以及（4）双相连续性的形成。在这项工作中研究的各种共聚物中，PPO共聚物在液滴聚结期间可以很容易地从界面中去除，并稳定次要纤维相的曲率，促进共连续形态的形成。相反，其他基于烯烃的相容剂（EPDM，OBC，PP-OBC和POE）则表现出独特的空间排斥作用，从而阻止了液滴的聚结。此外，共连续间隔随相容剂体系结构而变化。出人意料的是，在添加10 wt％的PPO共聚物后，共连续间隔从HDPE / iPP的45 / 55-60 / 40范围大大扩大到40 / 60-70 / 30的范围。