[Plastic] Polyethylene upgrade recycling: after modification, it can be used as an adhesive to firmly adhere to metal

Recently, researchers at the University of California, Berkeley invented a new chemical process that can recycle waste plastic bags (mainly polyethylene PE) and convert them into more valuable adhesives, realizing the upgrade of polyethylene Recycling.

According to reports, UC Berkeley professor of organic chemistry and research team leader John Hartwig and his colleagues used a catalyst based on ruthenium (gold spheres in the middle) to add specific to the polyethylene polymer chain.

Researcher Katerina Malollari has made 11 attempts and it is difficult to separate the water-based latex paint from Ox-LDPE, which was basically difficult to adhere to ordinary plastics before.

"Polyethylene chains usually have 2,000 to 10,000 carbon atoms, and each carbon atom has two hydrogen atoms-in fact, it is a sea of ​​CH2 groups called methylene groups.

Considering that solid recycled plastics need to be melted, this requires that the catalyst used for polyethylene recycling and modification can work in high temperature and non-polar solvents in order to be mixed with non-polar polyethylene.

Hartwig and postdoctoral assistant Liye Chen studied a ruthenium-based catalyst (polyfluororuthenium porphyrin) that can meet these requirements and can add OH groups to the polymer chain without polymerizing the highly reactive hydroxyl groups.

The researchers found that catalysis chemically changes less than 10% of the polymer, but it greatly enhances its ability to adhere to other surfaces.

Professor Hartwig said that the current process is not economical enough in industry, but it can be improved.

(Keyword: Polyethylene)