Overall migration and kinetics of release of antioxidant compounds from citrus extract-based active packaging

Synthesis and Properties of a Novel Reactive and Low-Migration-Resistant Antioxidant and Its Application in Rubber Composites

The addition of antioxidants to rubber is one of the most economical and effective methods for delaying rubber aging. However, antioxidant migration can cause environmental pollution. To address this issue, a new reactive antioxidant was synthesized via the chemical bonding of glycidyl methacrylate (GMA) and p-aminodiphenylamine (PPDA). The product was characterized by Fourier-transform infrared spectroscopy, which confirmed the successful reaction between GMA and PPDA, resulting in a compound with the expected structure. The mixture was then combined with a composite of styrene-butadiene rubber and carbon black. The tensile strength, antioxidant properties, migration, and RPA of the resulting materials were tested and compared with those of the commercial antioxidants N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-1,4-phenylenediamine, and poly(1,2-dihydro-2,2,4-trimethylquinoline). After the glycidyl methacrylate antioxidant was grafted onto p-aminodiphenylamine, it became highly compatible with and dispersed in the rubber matrix. The antiaging and antimigration properties of the rubber antioxidants were enhanced without damaging the mechanical properties of the rubber matrix. The short-term and long-term antiaging and antimigration properties of this antioxidant are superior to those of commercially available antioxidants.

Phenolic Compounds in Active Packaging and Edible Films/Coatings: Natural Bioactive Molecules and Novel Packaging Ingredients

In recent years, changing lifestyles and food consumption patterns have driven demands for high-quality, ready-to-eat food products that are fresh, clean, minimally processed, and have extended shelf lives. This demand sparked research into the creation of novel tools and ingredients for modern packaging systems. The use of phenolic-compound-based active-packaging and edible films/coatings with antimicrobial and antioxidant activities is an innovative approach that has gained widespread attention worldwide. As phenolic compounds are natural bioactive molecules that are present in a wide range of foods, such as fruits, vegetables, herbs, oils, spices, tea, chocolate, and wine, as well as agricultural waste and industrial byproducts, their utilization in the development of packaging materials can lead to improvements in the oxidative status and antimicrobial properties of food products. This paper reviews recent trends in the use of phenolic compounds as potential ingredients in food packaging, particularly for the development of phenolic compounds-based active packaging and edible films. Moreover, the applications and modes-of-action of phenolic compounds as well as their advantages, limitations, and challenges are discussed to highlight their novelty and efficacy in enhancing the quality and shelf life of food products.

Enhancement of aging resistance of EPDM rubber by natural rubber‐g‐N (4‐phenylenediamine) maleimide as a grafted antioxidant

A new antioxidant was prepared by graft copolymerization of N (4‐phenylenediamine) maleimide (pPDAM) onto natural rubber (NR). Fourier transform infrared technique was used to confirm the grafting of (pPDAM) onto the NR backbone. The grafted copolymer (NR‐g‐pPDAM) was incorporated into the ethylene propylene diene monomer rubber (EPDM) rubber mix as an antioxidant. For comparison purposes, a widely used antioxidant N‐(1,3‐dimethylbutyl)‐N′‐phenyl‐p‐phenylenediamine (6PPD) was used in addition to a blank sample without antioxidant. The rheometric characteristics of EPDM vulcanizates were determined using an oscillating disc rheometer. Different mechanical properties of the EPDM vulcanizates were measured before and after exposure to thermal and ultraviolet/ozone (UV/O3) accelerated aging. The results revealed that the grafted antioxidant NR‐g‐pPDAM is more efficient, for EPDM rubber vulcanizates than the commercial antioxidant (6PPD). EPDM containing grafted (NR‐g‐pPDAM) antioxidant exhibited promising properties, such that it is expected to fulfill major requirements of industrial, automotive, and construction applications.