Metal species with different size (single atoms, nanoclusters, and nanoparticles) show different catalytic behavior for various heterogeneous catalytic reactions. It has been shown in the literature that many factors including the particle size, shape, chemical composition, metal–support interaction, and metal–reactant/solvent interaction can have significant influences on the catalytic properties of metal catalysts. The recent developments of well-controlled synthesis methodologies and advanced characterization tools allow one to correlate the relationships at the molecular level. In this Review, the electronic and geometric structures of single atoms, nanoclusters, and nanoparticles will be discussed. Furthermore, we will summarize the catalytic applications of single atoms, nanoclusters, and nanoparticles for different types of reactions, including CO oxidation, selective oxidation, selective hydrogenation, organic reactions, electrocatalytic, and photocatalytic reactions. We will compare the results o...

Metal Catalysts for Heterogeneous Catalysis: From Single Atoms to Nanoclusters and Nanoparticles.

The antibacterial action of silver is utilized in numerous consumer products and medical devices. Metallic silver, silver salts, and also silver nanoparticles are used for this purpose. The state of research on the effect of silver on bacteria, cells, and higher organisms is summarized. It can be concluded that the therapeutic window for silver is narrower than often assumed. However, the risks for humans and the environment are probably limited.

Silver as Antibacterial Agent: Ion, Nanoparticle, and Metal

https://bura.brunel.ac.uk/bitstream/2438/18351/1/FullText.pdf

An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling.

In this article, several applications of nanomaterials in food packaging and food safety are reviewed, including: polymer/clay nanocomposites as high barrier packaging materials, silver nanoparticles as potent antimicrobial agents, and nanosensors and nanomaterial-based assays for the detection of food-relevant analytes (gasses, small organic molecules and food-borne pathogens). In addition to covering the technical aspects of these topics, the current commercial status and understanding of health implications of these technologies are also discussed. These applications were chosen because they do not involve direct addition of nanoparticles to consumed foods, and thus are more likely to be marketed to the public in the short term.

Applications of nanotechnology in food packaging and food safety: Barrier materials, antimicrobials and sensors

Physical and mechanical properties of PLA, and their functions in widespread applications - A comprehensive review.

The thermoforming capacity of a number of blends of an ethylene-vinyl alcohol copolymer (EVOH-32, with 32 mol % ethylene) with amorphous polyamide (aPA) and/or Nylon-containing ionomer with interest in multilayer food packaging structures have been studied. These blends were vacuum-thermoformed between 100 and 150°C onto male molds of different shapes and areal draw ratios. It was found that EVOH/aPA extruded blends did not improve the inherently poor formability of EVOH alone. In contrast, significant improvements in thermoformability were achieved by blending EVOH with a compatibilized-ionomer. Optimum forming capacity was achieved in a ternary blend by addition of a compatibilized-ionomer to EVOH/aPA blends in the range of 140–150°C. Analysis of wall thickness data obtained in the thermoformed parts showed that wall thickness was significantly affected by the ionomer and amorphous polyamide content in the blend. The ternary blend showed a lower thickness reduction in the critical areas, as well as a higher uniformity in the part. A finite element analysis was used to evaluate the wall thickness distribution and the modeling results were compared with the thermoforming experiments. The simulations were performed for the vacuum-forming process employing a nonlinear elastic material model. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 96: 3851–3855, 2004

Study of the thermoformability of ethylene‐vinyl alcohol copolymer based barrier blends of interest in food packaging applications

The permeation of five volatile organic compounds found in Iberian ham aroma (n-hexanal, n-hexanol, n-decane, ethyl caproate, and d-limonene) through films of ultra-low-density polyethylene (ULDPE)...

Food aroma mass transport in metallocene ethylene-based copolymers for packaging applications

Improving polyphenolic thermal stability of Aristotelia Chilensis fruit extract by encapsulation within electrospun cyclodextrin capsules

Simplified extraction procedures (avoiding Soxhlet treatment and/or hemicellulose removal) were evaluated to valorize waste biomass from Posidonia oceanica leaves, obtaining cellulosic fractions and nanocrystals, which were subsequently used to produce films from their aqueous suspensions. Cellulose purification significantly improved mechanical and barrier properties of the films obtained from the fractions, while the extracted nanocrystals yielded films with remarkably improved properties, outperforming most benchmark biopolymers. The lipids initially present in the fractions without Soxhlet treatment were not completely digested by the hydrolysis treatment, having a positive impact on the water vapor permeability of the films (up to 63% drop), although negatively impacting oxygen permeability (increased by 20–30-fold). On the contrary, some hemicelluloses present in the less purified fractions, strongly interacting with cellulose, remained in the extracted nanocrystals leading to enhanced mechanical properties (45% higher tensile strength and 2-fold increase in the elongation at break), but lower water barrier (up to 70% higher permeability than the pure cellulose nanocrystals) due to their hydrophilic character. Films produced from the less purified nanocrystals showed the best compromise between mechanical and barrier performance, while offering a great advantage in terms of sustainability and reduced costs.

/pdf/cellulose-nanocrystal-based-films-produced-by-more-32i7i8wufh.pdf

Cellulose nanocrystal-based films produced by more sustainable extraction protocols from Posidonia oceanica waste biomass

PVdC and aluminium foil (or aluminium metallization) have traditionally been used as flexible high barrier materials in the design of packages for perishable foodstuffs. During recent years new pol...

Rafael Gavara

Papers

Study of the thermoformability of ethylene‐vinyl alcohol copolymer based barrier blends of interest in food packaging applications

Food aroma mass transport in metallocene ethylene-based copolymers for packaging applications

Improving polyphenolic thermal stability of Aristotelia Chilensis fruit extract by encapsulation within electrospun cyclodextrin capsules

Cellulose nanocrystal-based films produced by more sustainable extraction protocols from Posidonia oceanica waste biomass

Review: Alternative high barrier polymers for food packaging Revisión: Polimeros de alta barrera para el envase de alimentos