Nanocomposite films based on low-density polyethylene (LDPE) containing carvacrol were prepared and characterized with the aim to get antimicrobial active packaging. Organo-modified montmorillonite (MMT) was used as filler. The weak interaction between LDPE and clay led to the formation of intercalated systems. On the other hand, strong interaction between carvacrol and organosilicate allowed a good dispersion of the oil into the clay galleries, promoting the swelling of MMT stacks and a higher polymer/clay interface. As a result, carvacrol was protected against thermal degradation and its release from the films was efficiently delayed. Moreover, outstanding thermal oxidative stability as well as improved oxygen barrier properties were detected in the nanocomposite containing carvacrol. The presence of clay and carvacrol also increased LDPE crystallinity, due to an enhanced nucleation activity, while the mechanical properties of the films were slightly affected. The antimicrobial properties of carvacrol containing films were tested, showing a significant activity against several bacterial strains, which is preserved in presence of the clay. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineer

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Treatment with boiling 6 M HCl increases up to 30 times the intrinsic antioxidant potency of spent coffee grounds, leading to a versatile multifunctional material (hydrolyzed spent coffee grounds, HSCG). Spectral and morphological analyses suggest that the remarkable potentiation of the antioxidant activity is due to efficient removal of the hydrolyzable components, mainly carbohydrates, making the polyphenol-rich component available for interaction with free radicals and oxidizing species. HSCG efficiently protects hepatocarcinoma (HepG2) cells from oxidative stress-induced injury and delays lipid peroxidation in fish and soybean oils. Moreover, films made of polyethylene/2% HSCG blends display greater stability to thermal and photo-oxidative degradation. HSCG may thus represent an easily accessible and sustainable alternative to currently available biomaterials with intrinsic antioxidant properties for biomedical, industrial, and technological applications

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The synthesis, structural characterization and properties of a new bioinspired phenolic polymer (polyCAME) produced by oxidative polymerization of caffeic acid methyl ester (CAME) with horseradish peroxidase (HRP)-H2O2 is reported as a new sustainable stabilizer toward polyethylene (PE) thermal and photo-oxidative degradation. PolyCAME exhibits high stability toward decarboxylation and oxidative degradation during the thermal processes associated with PE film preparation. Characterization of PE films by thermal methods, photo-oxidative treatments combined with chemiluminescence, and FTIR spectroscopy and mechanical tests indicate a significant effect of polyCAME on PE durability. Data from antioxidant capacity tests suggest that the protective effects of polyCAME are due to the potent scavenging activity on aggressive OH radicals, the efficient H-atom donor properties inducing free radical quenching, and the ferric ion reducing ability. PolyCAME is thus proposed as a novel easily accessible, eco-friendly, and biocompatible biomaterial for a sustainable approach to the stabilization of PE films in packaging and other applications.