What is it about?
In this paper, we report a new adhesion method for polyolefins, specifically polyethylene and polypropylene. We developed a polyurethane adhesive that can blend with these plastics. This adhesive forms a mixed layer with polyethylene and polypropylene when heated. When the heating is stopped and this layer is cooled, phase separation and recrystallization of the polyolefins occur simultaneously, resulting in the formation of needle-like polyolefin crystals. These needle-like crystals physically fix the interface, much like nailing it.
Featured Image
Why is it important?
About half of the plastics produced worldwide are polyethylene and polypropylene. These polyolefins are rarely recycled and are usually discarded after a single use. One reason for this is that polyolefins do not mix well with other plastics and have poor adhesion, so they need to be separated for recycling. In general, plastic waste contains many different types of plastics mixed together, and sorting them by type requires a lot of time and money, making it economically unfeasible. To recycle these materials without separating them, a simple method to bond polyolefins with other materials was needed.
Perspectives
This study proposes a completely new approach to bonding polyethylene and polypropylene, which has long been a challenging task. Specifically, it presents design guidelines for polyurethane materials that can blend with these polyolefins, along with analytical data on the blending process and a discussion of the underlying mechanism. In addition, the formation of needle-like polyolefin crystals is a highly intriguing phenomenon from a basic science perspective.
Ph.D. Yoshihiko Shiraki
Tosoh Corporation
Read the Original
This page is a summary of: Adhesion to Untreated Polyethylene and Polypropylene by Needle-like Polyolefin Crystals, Macromolecules, March 2023, American Chemical Society (ACS),
DOI: 10.1021/acs.macromol.2c02503.
You can read the full text:
Contributors
The following have contributed to this page
