Document Type : Original research
Authors
1 Department of Chemistry, Payame Noor University, P.O. Box; 19395-36972, Tehran, Iran
2 Department of Polymer Processing, Polymer and Petrochemical Institute, P.O.Box: 14965-115, Tehran, Iran
Abstract
Growing interest in sustainable polymer additives has encouraged the replacement of synthetic phenolic antioxidants with naturally derived alternatives. In this study, oleuropein extracted from discarded olive leaves was chemically modified with vinyltrimethoxysilane (VTMS) and utilized as a reactive antioxidant for low-density polyethylene (LDPE), a polymer widely used in food packaging applications. Different amounts of the modified oleuropein were incorporated into LDPE through peroxide-initiated reactive melt blending. The successful incorporation of the modified antioxidant into the polymer matrix was supported by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance analysis, extraction resistance, and overall migration results. The prepared materials were characterized by oxidative induction time (OIT), thermogravimetric analysis, tensile testing, scanning electron microscopy, differential scanning calorimetry, and rheological measurements. The incorporation of modified oleuropein significantly improved the thermo-oxidative stability of LDPE, increasing the OIT from approximately 6 min for neat LDPE to about 18 min for the modified samples. In addition, the modified antioxidant exhibited excellent resistance to extraction while maintaining overall migration values well below the regulatory limit. These findings demonstrate that VTMS-modified oleuropein is a promising naturally derived antioxidant for enhancing the thermo-oxidative performance of polyethylene through an industry-relevant reactive extrusion process.
Graphical Abstract
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Keywords
- Low-density polyethylene (LDPE)
- modified oleuropein
- reactive extrusion
- thermo-oxidative stability
- overall migration
Main Subjects
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