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A method was developed for generating transparent and hydrophobic nanolayers chemisorbed onto flexible substrates of Polyethylene terephthalate – Silicon Oxide (PET-SiOx). In particular, the effect of the ratio between the substrate surface and concentration of reagent on the nanocoating process was analyzed with the aim of pursuing an optimization of the above method in an industrial application perspective. Measurements of the contact angle carried out on the SiOx PET film samples, showed a hydrophobicity growth for surface values lower than 100 cm2 and then decreased for larger surfaces (with 1% v/v of reagent), while remaining considerably higher than the value of the virgin substrate. The differential scanning calorimetry and the UV-visible transmittance analysis show that there are no significant variations compared with the PET film SiOx as such. [ABSTRACT FROM AUTHOR]

The aim of this work is to investigate possible solutions to realize antimicrobial-incorporated biodegradable coatings for active food packaging films. At this purpose, the antimicrobial agent (Ethyl-Nα-dodecanoyl-L-arginate, LAE), a cationic surfactant, was added at different percentages to a PLA coating solution, which was spread on a BOPET substrate. Films were characterized in order to obtain information on LAE interaction with the polymer matrix and its effect on thermal stability and functional performance of the films. To assess the films activity and to verify the efficacy of such solutions, microbial tests were carried out using E. Coli CECT 434 strain as pathogenic agent. [ABSTRACT FROM AUTHOR]

The aim of this work is to compare the scavenging performance and oxygen absorption kinetics of active food packaging films, produced by adding the same percentage of two different formulations of polymeric oxygen scavengers, both copolyester based and designed for PET packaging. Rheological analyses were conducted to investigate possible differences among the macromolecular structure, while oxygen absorption measurements in continuous were performed to evaluate the influence of the different composition on the scavenging phenomenon. The results revealed differences in the molecular chains, and an enhanced formulation for one of the scavengers, with increased scavenging power and exhaustion times. [ABSTRACT FROM AUTHOR]

In this work an active barrier system consisting of a thin and transparent film based on polyethylene terephthalate (PET) was studied. Dynamic oxygen absorption measurements were performed at different values of relative humidity and temperature, pointing out that humidity is a key factor in activating the oxidation of the polymer sample. Moreover, the thermal and optical properties of the films were investigated and a good correlation was found between the crystallinity increase and the consequent transparency reduction occurring after the oxygen absorption. [ABSTRACT FROM AUTHOR]

Copolyamide nanocomposites, based on sepiolite needle-like clay, were prepared through melt extrusion at different silicate loadings. The hybrid materials were characterized in terms of both thermal and rheological properties. A fine dispersion of the nanoparticles was evidenced by the dynamic rheological behavior of the composites. Moreover, the presence of sepiolite does not cause changes in the overall crystallinity degree and crystal structure compared to the neat polymer. The effect of an increasing percentage of nanofiller on the mechanical performances of the nanocomposites was also evaluated. A remarkable combination of high stiffness and toughness, not already found in literature for this kind of nanocomposites, was achieved at the lower silicate amount. [ABSTRACT FROM AUTHOR]

In this work we report on the functionalization of a natural sodium montmorillonite (MMT) with (3- glycidyloxypropyl)trimethoxysilane by a silylation procedure and on its use as nanofiller in melt compounding of polyethylene nanocomposites. The obtained organosilylated clay showed higher interlayer spacing than the original MMT and higher thermal stability with respect to most of commercial organoclays modified with alkylammonium salts. Its addition (at 5wt%) to two different polyethylene matrices (a low density polyethylene, LDPE, and a high density polyethylene, HDPE), processed in a pilot-scale twin-screw extruder, allowed to produce hybrids with nanoscale dispersion of the filler, as demonstrated by X-ray diffraction. Thermogravimetric and differential scanning thermal analyses point out that the obtained nanocomposites do not show noticeable changes in the thermal behavior of both LDPE and HDPE, even if a slight reduction in the overall bulk crystallinity was observed in presence of the nanofillers. [ABSTRACT FROM AUTHOR]

A preliminary investigation was carried out on the possibility to improve the protective action offered by the standard multilayer structures used to encapsulate photovoltaic devices. With this aim, a commercial active barrier PETbased material, able to absorb oxygen when activated by liquid water, was used to produce flexible and transparent active barrier films, by means of a lab-scale film production plant. The obtained film, tested in terms of thermal, optical and oxygen absorption properties, shows a slow oxygen absorption kinetics, an acceptable transparency and an easy roll-toroll processability, so proving itself as a good candidate for the development of protective coating for solar cells against the atmospheric degradation agents like the rain. [ABSTRACT FROM AUTHOR]

The present work focuses on the possibility of conveniently tuning materials in PLA based nanocomposites in order to improve their processability in manufacturing processes where extensional flow is mainly involved. Nanocomposites at a constant silicate loading were produced by melt compounding, using a commercial polylactide grade (PLA 4032D) and two different organo-silicates (Cloisite 30B and Nanofil SE3010). A morphological characterization in solid and molten state, realized by TEM investigations and shear rheological measurements, firstly pointed out the influence of composition on the nanostructure of the hybrid systems. All the samples were then submitted to uniaxial stretching and the rheological response of the different nanocomposites was correlated to the initial nanostructure and the different polymer-clay affinity. [ABSTRACT FROM AUTHOR]

In this work the correlation between the thermoformability of different grades of polylactide acid (PLA 4032D, PLA 4042D and PLA 2003D) and their mechanical, thermal, and rheological properties was explored. In particular, hot tensile tests, at different stretching temperatures and crosshead speeds, were performed in order to identify an optimum windows of temperature and strain rate for improved thermoforming performance. The properties measured from the creep experiments were correlated with the propensity of PLA sheet to sag, while the unrecovered strains by the creep recovery tests were associated to mold replication attitude of the materials investigated. [ABSTRACT FROM AUTHOR]

The aim of this work is to investigate possible solutions to realize active, transparent PET film suitable for packaging oxygen sensitive foods. At this purpose, monolayer active PET films at different oxygen scavenger concentrations and multilayer active ones were produced by cast extrusion laboratory scale equipments. To assess their activity and to verify the efficacy of such solutions, O2 absorption analyses were carried out in continuous by an innovative oxygen meter. [ABSTRACT FROM AUTHOR]

This work focuses on the possibility of improving performance properties of polylactide films for packaging applications by melt mixing silicate nanoparticles within PLA matrix. Nanocomposites at various silicate loadings were produced by cast-film extrusion using two different temperature profiles. Oxygen barrier and mechanical properties of the produced films were investigated and correlated to their nanostructure through analytical techniques sensitive to different aspect of the same morphology, such as TEM, XRD and rheological analyses. [ABSTRACT FROM AUTHOR]

In this work the protective efficacy and stability against UV weathering of polymeric nanocomposites for concrete (CLS) surface protection have been evaluated. In particular, nanocomposite hybrids were prepared dispersing a commercial organomodified montmorillonite (Cloisite 30B) in two different polymeric matrices, one based on fluoroelastomers (Fluoline CP), the other on silane and siloxane (Antipluviol S). The obtained systems were characterized by several techniques (SAXD, DSC, TGA, FT-IR, contact angle measurements, colorimetry), before and after accelerated aging due to UV exposure, in order to evaluate the effect of the nanoscale dispersion of the organoclay on the properties and the UV stability of the treatments. [ABSTRACT FROM AUTHOR]