Polypropylene (PP) and Polyethylene (PE) are widely used commodity plastics in packaging industry such as detergent bottles. To produce plastic detergent bottles, very often extrusion blown molded PE-HD as a body and injection molded PP as a screw cap are used. Separation of individual polymer type is difficult due to the similar density. Unfortunately, the melt blending of recycled post-consumer detergent bottle waste leads to deterioration of mechanical properties. Additionally, the percentage of rPP contamination in recycled PE-HD (rPE-HD) from post-consumer bottle waste can be varied depending on local waste composition and different sorting quality. This work investigates the effect of various contamination scenarios with different percentage of rPP from bottle caps in rPE-HD from bottle waste as well as their compatibilization with olefin block copolymer (OBC) on mechanical, thermal, and rheological properties. Moreover, the low temperature tensile properties of blends with OBC are also investigated in this study. The results showed that the increasing rPP contamination leads to deteriorating elongation at break and tensile impact strength. Furthermore, the addition of OBC as a compatibilizer into worse-case contamination scenario (15 wt% rPP in rPE-HD) significantly improved elongation at break and tensile impact strength. Scanning electron microscopy (SEM) confirms the improvement in adhesion between rPP and rPE-HD from recycled bottle waste with the addition of OBC as a compatibilizer. Rheological measurements reveal the interfacial interaction among rPP, rPE-HD and OBC. The low temperature tensile test demonstrated that the addition of OBC as a compatibilizer improved low temperature tensile elongation at break.

聚丙烯（PP）和聚乙烯（PE）是包装工业中广泛使用的商品塑料，例如洗涤剂瓶。为了生产塑料洗涤剂瓶，通常使用挤吹成型的PE-HD作为主体，而注射成型的PP作为螺帽。由于相似的密度，很难分离单个聚合物类型。不幸的是，回收的消费后洗涤剂瓶废料的熔融共混导致机械性能的降低。此外，消费后瓶废物中的再生PE-HD（rPE-HD）中rPP污染的百分比可以根据当地废物的成分和不同的分类质量而变化。这项工作研究了各种污染情景的影响，即从瓶废物中提取的rPE-HD中瓶盖的rPP百分比不同，以及它们与烯烃嵌段共聚物（OBC）的相容性对机械，热学和流变性的影响。此外，在这项研究中还研究了与OBC的共混物的低温拉伸性能。结果表明，rPP污染的增加导致断裂伸长率和拉伸冲击强度的降低。此外，将OBC作为相容剂添加到更坏的情况下（rPE-HD中的rPP为15 wt％）显着提高了断裂伸长率和拉伸冲击强度。扫描电子显微镜（SEM）证实了通过添加OBC作为增容剂，可回收瓶废料中rPP和rPE-HD之间的粘附性得到了改善。流变学测量揭示了rPP，rPE-HD和OBC之间的界面相互作用。低温拉伸试验表明，加入OBC作为增容剂可改善低温拉伸断裂伸长率。