<i>i</i>PP/HDPE blends compatibilized by a polyester: An unconventional concept to valuable products.

Abstract

Polyolefins are the most widely used plastics accounting for a large fraction of the polymer waste stream. Although reusing polyolefins seems to be a logical choice, their recycling level remains disappointingly low. This is mainly due to the lack of large-scale availability of efficient and inexpensive compatibilizers for mixed polyolefin waste, typically consisting of high-density polyethylene (HDPE) and isotactic polypropylene (<i>i</i>PP) that, despite their similar chemical hydrocarbon structure, are immiscible. Here, we describe an unconventional approach of using polypentadecalactone, a straightforward and simple-to-produce aliphatic polyester, as a compatibilizer for <i>i</i>PP/HDPE blends, especially the brittle <i>i</i>PP-rich ones. The unexpectedly effective compatibilizer transforms brittle <i>i</i>PP/HDPE blends into unexpectedly tough materials that even outperform the reference HDPE and <i>i</i>PP materials. This simple approach creates opportunities for upcycling polymer waste into valuable products.