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The influence of the different contents of organo‐modified montmorillonite clay (1 and 3%wt.) and two essential oils (Carvacrol and Eugenol ‐ 2 and 6%wt.) when incorporated into low‐density polyethylene films (LDPE) was characterized by X‐ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). This study shows the potential of montmorillonite clay as a carrier of carvacrol and eugenol essential oils, ClayC and ClayE, respectively, into LDPE nanocomposites. To prepare the nanocomposites, oils and clay hybrid were mixed and added to polyethylene using a homogenizer. The clay increased the thermal stability of the essential oils. PE/ClayC and PE/ClayE nanocomposites showed increased crystallinity as a function of the amount of hybrid; this was more significant for the PE/ClayC system. Increased crystallinity suggests that clay acts as nucleating agent, due its intercalated/exfoliated configuration. The results contribute to obtaining a more efficient nanocomposite system for subsequent applications, such as active packaging. POLYM. COMPOS., 39:4034–4040, 2018. © 2017 Society of Plastics Engineers

A critical issue in active packaging development using essential oils (EOs) is the high concentrations of these to obtain antimicrobial activity in the films. Therefore, this work was carried out to develop nanocomposite films, pursuing a potential minimal EO concentration with antimicrobial effectiveness, which could be applied in packaging. The films were prepared using lowdensity polyethylene (LDPE) containing a hybrid of montmorillonite and essential oil (MMT-EO), using two different EOs, carvacrol and eugenol, with 2 and 6 wt% oil concentration. The films were obtained in three steps. In the first (hybrid production), mixtures of montmorillonite clay with eugenol or carvacrol EOs were prepared. In the second (hybrid incorporation), these hybrids were incorporated into LDPE, obtaining LDPE/MMT-EO nanocomposites. Finally, a thermoforming process prepared the polymeric films. The samples were characterized by XRD and mechanical, contact angle and antimicrobial properties. The XRD results showed higher crystallinity for LDPE/MMT-EO compared to LDPE. The MMT was exfoliated into lamella forms, which could work as a physical barrier, reducing the oil diffusion. Besides, the contact angle results showed an increase in the hydrophilicity with the addition of the hybrids, which improved the antimicrobial action of the film. LDPE/MMT-E3 (1 wt% MMT and 2 wt% eugenol) showed the highest crystallinity, oil diffusivity, and mechanical and antimicrobial properties. These samples presented a reduction of a 2 log count of Staphylococcus aureus. The sum of the structural and antimicrobial properties of the LDPE/MMT-E3 film indicates its potential for food packaging.

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The aims of this work is the development of low density polyethylene/thermoplastic starch (LDPE/TPS) blend with biodegradable characteristic and antibacterial activity, in which the incorporation of limonene (LM) acts with antibacterial action and citric acid (AC) as compatibilizer. LDPE/TPS blends were prepared with the incorporation of different proportions of AC and LM. The mechanical test results showed that the LDPE/TPS blends with incorporated LM had a reduction in the mechanical resistance, since the differential scanning calorimetry (DSC) analyzes showed lower enthalpy value, suggesting the plasticizer effect of the LMfavorable characteristic for processability, and the AC was efficient as a compatibilizer.