Utilizzo di nanocompositi polimerici per la conservazione di materiali lapidei

In questo lavoro sono stati studiati sistemi nanocompositi polimerici per la protezione ed il consolidamento di materiali lapidei. L’obiettivo è quello di incrementare la compatibilità e di conseguenza l’efficacia protettiva e/o consolidante di prodotti polimerici commerciali utilizzati nel settore del restauro della pietra. A tale scopo sono stati preparati e caratterizzati nanocompositi polimerici aggiungendo alle matrici pure differenti quantità di filler inorganici. I risultati dei trattamenti condotti su campioni di tufo giallo Napoletano, hanno mostrato che la presenza di piccole quantità di nanofiller, ben dispersa nella matrice polimerica, ha effetti promettenti per scopi conservativi, incrementando sia l’efficacia protettiva che le proprietà consolidanti delle resine pure. In particolare i sistemi nanocompositi ritardano i fenomeni di degrado dovuti all’acqua, poiché riducono gli assorbimenti d’acqua liquida e limitano la velocità di diffusione del vapore acqueo. Inoltre essi promuovono un’efficace azione consolidante attraverso il decremento dei fenomeni di polverizzazione delle superfici ed il miglioramento della resistenza a compressione senza indurre significative alterazioni cromatiche delle superfici trattate

EFFECT OF ACCELERATED WEATHERING ON STRUCTURE AND COMFORT FACTORS OF COMMERCIAL POLYURETHANE FOAMS FOR MATTRESS

In this work three commercial flexible polyurethane foams used for mattress have been submitted to artificial accelerated weathering in a climatic chamber in order to investigate its effect on their structure and some functional properties of interest for bedding applications. FT-IR and colorimetric analyses demonstrated that during weathering all the three foams undergo oxidation of the polyether soft segments. The resulting changes in the chemical structure, morphology and molecular mobility of the foams affected their comfort in static conditions, giving a general reduction of the hysteresis loss, surface firmness and sag factor, more significant for the foams having slow recovery rate after compression

Copolyamide/sepiolite nanocomposites with enhanced stiffness and toughness

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

Processing-structure-properties relationships in PLA nanocomposite films

This work deals on the possibility to improve performances of PLA-based nanocomposite films, for packaging applications, through conveniently tuning materials and processing conditions in melt compounding technology. In particular, two types of polylactic acid and different types of filler selected from montmorillonites and bentonites families were used to prepare the hybrid systems by using a twin-screw extruder. The effect of biaxial drawing on morphology and properties of the nanocomposites, produced by film blowing, was investigated

Novel antimicrobial polymer films active against bacteria and fungi

We report on the synthesis and the characterization of an azobenzene-based compound. The molecule shows high antimicrobial activity against Staphilococcus aureus and Candida albicans, as demonstrated by in vitro microbiological test in solution. Two antimicrobial polymeric systems were realized introducing this antimicrobial molecule in two polyolefin matrices. The polymeric materials containing different percentages of azo-compound were mold-casted and the obtained films were tested in vitro against the same Gram-positive bacterium and fungus. The films show biocide activity at low percentage of azo dye (up to 0.01%), holding promise for the fabrication of bacteria-resistant polymer films by means of simple melt processing

Antimicrobial polymer films for food packaging

New antimicrobial polymeric systems were realized introducing new antimicrobial azo compounds in PP and LDPE matrices. The polymeric materials containing different percentage of azo compounds were mold-casted and the obtained film were tested in vitro against Gram+ and Gram− bacteria and fungi. These results hold promise for the fabrication of bacteria-resistant polymer films by means of simple melt processing with antimicrobial azo-dye

Healthy lifestyle promotion in primary schools through the board game Kaledo: a pilot cluster randomized trial

The board game Kaledo was proven to be effective in improving nutrition knowledge and in modifying dietary behavior in students attending middle and high school. The present pilot study aims to reproduce these results in younger students (7â\u80\u9311 years old) attending primary school. A total of 1313 children from ten schools were recruited to participate in the present study. Participants were randomized into two groups: (1) the treatment group which consisted of playing Kaledo over 20 sessions and (2) the no intervention group. Anthropometric measures were carried out for both groups at baseline (prior to any treatment) and at two follow-up post-assessments (8 and 18 months). All the participants completed a questionnaire concerning physical activity and a 1-week food diary at each assessment. The primary outcomes were (i) BMI z-score, (ii) scores on physical activity, and (iii) scores on a dietary questionnaire. BMI z-score was significantly lower in the treated group compared to the control group at 8 months. Frequency and duration of self-reported physical activity were also significantly augmented in the treated group compared to the control group at both post-assessments. Moreover, a significant increase in the consumption of healthy food and a significant decrease in junk food intake were observed in the treated group. Conclusion: The present results confirm the efficacy of Kaledo in younger students in primary schools, and it can be used as a useful nutritional tool for obesity prevention programs in children. (Table presented.