Additive Extraction from Polyolefin Matrices for Plastic Recycling

November 14, 2025

The growing production and consumption of polyolefins highlights the need for improved recycling methods. Accelerated solvent extraction of antioxidants Irganox 1076, Irganox 1010, and Irgafos 168 from polypropylene and polyethylene was studied in this report, on the scope of the research of plastic deformulation-based recycling. Two design of experiments were performed on a polypropylene and on a high-density polyethylene to identify temperature, static time, and the percentage of co-solvent in the solvent mixture as the most important parameters in plastic ASE. Several polypropylene and polyethylene grades were used with different antioxidant species. Polypropylene enabled the extraction of larger amounts than polyethylene. I1076 proved to be the most efficiently extracted antioxidant, whereas extraction of I1010 is harder due to its larger structure and molecular weight, which slow down diffusion. It was observed that with enough time, additives were able to reach the surface, even with fillers. Different solvent and swelling agent combinations were tested, and it was observed that solvent composition has impact on ASE yield. Acetone with 5% (v/v) hexane proved to be the best option for additive extraction in a specific polypropylene charge, as predicted by the Hansen model. The polymer was cryoground to increase the extraction yield, and a recovery of 62% (w/w) and 60% (w/w) of I1076 and I168, respectively, was found at 120◦C, 15 min, 3 cycles, and acetone with 5% (v/v) hexane, which were identified as the best extraction conditions.

Authors in the community:

• 

  M

  Maria Leonor Sousa Rocha

  ist1100430

Supervisors of this institution:

• 

  M

  Maria Filipa Gomes Ribeiro

  ist11988

chemical-engineering - Chemical engineering

por - Portuguese

Instituto Superior Técnico