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Biodegradable poly(vinyl alcohol) (PVOH) based foams were prepared through an ecofriendly methodology. Different amount of recycled multilayer cartons (MC), composed of cellulose and low-density polyethylene (80/20 wt/wt), were added as a direct cellulose source to PVOH. Foams were realized through a modified overrun process without using chemical agents or promoting chemical reactions. In particular, the air entrapped during the high-speed mixing of the PVOH/MC water dispersion was able to create a porous morphology. The effects of the addition of MC on microstructure, swelling behavior, and mechanical and thermal properties of foams were investigated. Materials were characterized by a dual-pore structure. Improvements of the swelling behavior, mechanical properties, and thermal stability were recorded as a function of MC content. These findings can be considered as a result of a good interaction between filler and polymer. [ABSTRACT FROM PUBLISHER]

With the aim at controlling cellulose degradation phenomena, the natural aging of Whatman paper samples was simulated through different artificial aging processes: thermal oxidation in air at constant temperature, photo-oxidation under Xenon arc lamp, accelerating ageing in climatic chamber, and chemical oxidation with sodium methaperiodate. The cellulose degradation was studied by means of viscosimetric, Fourier transform infrared spectroscopy (FTIR), and wide angle X-ray scattering (WAXS) techniques together with thermogravimetric (TGA), mechanical, and optical analyses. All the treatments carried out were found to significantly modify paper structure and properties, the extent of the deterioration effects depending upon the aging kind. Direct correlations were, nevertheless, assessed among level of cellulose molecular degradation, formation of carboxyl, and/or carbonyl groups and paper strain at break. [ABSTRACT FROM AUTHOR]

With the aim of clarifying the complex shapes of the stress-strain curves of yarns such as wool and silk and improving the reproducibility of the experimental results achieved through their mechanical characterization, nylon 6,6 yarns consisting of one, three, nine, and thirty filaments are selected as a modeling system. Moreover, the uniaxial tensile properties of commercial nylon 6,6 yarns are investigated and compared with the corresponding properties of commercial wool and silk yarns. Moisture level plays a very relevant role in determining the mechanical behavior of yarns. With an increasing moisture level of conditioning, in fact, nylon 6,6, wool, and silk yarns show neat breaking points, and their stress-strain curves tend to assume the typical shape of the curve shown by respective single fibres. This suggests that high moisture levels minimize the multiple breakage phenomena occurring in the yarn. Moreover, for all the yarns investigated and, in particular, for wool, the process of conditioning at 100% RU reduces the variability of the experimental results, thus inducing a significant improvement in the precision and reproducibility of uniaxial tensile tests. [ABSTRACT FROM AUTHOR]