Work

Comparison of Recycled Polypropylene Sourced From Food and Nonfood Applications for Direct Food Contact Use

Year: 2026

Type: article

Abstract: ABSTRACT Polypropylene (PP) is a widely used polymer in packaging applications, which is often landfilled as part of #3–7 bales from material recovery facilities (MRFs). With rising demand for postconsumer PP, and its high composition in #3–7 bales, MRFs are increasing PP sorting capacity. Therefore, assessing chemical safety and physical quality becomes critical as design parameters for new products. Contamination emerges from various sources, for example, manufacturing, recycling and the original intended use (food compared with nonfood applications). Analysing the physical properties and contaminants/residual additives in postconsumer recycled (PCR) PP can provide guidance to improve cleaning, separation processes and quality reducing landfilling. PCR PP from #3–7 bale was sorted into two categories: food and nonfood applications. Each PCR PP type was exposed to a simulated recycling procedure and collected at each unit operation (washing, moulding, etc.) for analysis. It was determined nonfood‐application PCR PP contained higher quantitative phthalates, bisphenols and qualitative IAS/NIAS with inconsistent contaminant removal during washing. Nonfood‐application PCR PP possessed lower viscosity and molecular weight (Mw) across all categories except Mw in the unwashed sample compared with food‐grade PCR PP, likely due to contamination, polymer degradation or additive levels. This research identifies potential contaminants and additives in food‐ and nonfood‐application PCR PP from MRFs. These findings emphasise proper sorting for safe food‐grade feedstocks from postconsumer sources. These data indicate careful sortation is required to reduce exposure to chemicals of concern and unapproved additives in food packaging that comprised PCR PP.

Source: Packaging Technology and Science

DOI: 10.1002/pts.70059

Authors: Khairun Tumu, Keith Vorst, Greg Curtzwiler

Institution: Iowa State University

Language: English

Topic: Polymer crystallization and properties

Subfield: Polymers and Plastics

Field: Materials Science

Domain: Physical Sciences

SDG: Responsible consumption and production

Open Access status: hybrid

Estimated APC paid: $4,150