In this work the processability and the mechanical performance of polylactide acid (PLA) based blends with a sample of a new biodegradable medium-chain-length poly (hydroxyalkanoate) (PHA) were investigated. The two polymers are incompatible with scarce adhesion and with the dispersed PHA particles size increasing with the PHA content. Rheological tests in shear flow indicate that adding PHA improves the processability of the matrix by increasing the content of this second component in the blend, as observed also for the torque curves, due to the very low viscosity of this new sample of PHA. The processability is only slightly worsened in non-isothermal elongational flow as the melt strength decreases, but accompanied by an increase of the melt stretchability that improves the ability of the pure PLA matrix to produce thin films. Mechanical properties put in evidence a brittle–ductile transition adding PHA to PLA matrix. The elongation at break significantly increases when PHA is added, while the elastic modulus is significantly reduced only at higher contents of PHA. This has been interpreted in terms of both plasticization action of the PHA and also in terms of lubricant action of the PHA macromolecules that allows a better sliding of the PLA macromolecules subjected to solid deformation

Nanobiocomposites are a new class of biodegradable polymer materials with nanometric dispersion of inert particles in a biodegradable polymer matrix that show very interesting properties often very different from those of conventional-filled polymers and also biodegradability. An important issue in the applications of the biodegradable polymers is their easy degradability during processing due to the thermomechanical stress or to the presence of humidity. In this work, the thermomechanical degradation behavior of a nanobiocomposite made by a PLA-based blend and an organomodified montmorillonite has been investigated. The degradation kinetics has been followed by means of rheological, mechanical and morphological characterization. In particular, the influence of temperature and of the presence of humidity have been considered.The presence of the nanoparticles slightly increases the thermomechanical degradation of the pure matrix and in particular with increasing time and temperature processing. In the more severe conditions, indeed, the organomodifier undergoes some slight decomposition of the organomodifier of the clay because of the Hoffmann elimination. The radicals formed through this decomposition enhance the degradation of the matrix. However, this decomposition is at the first stage, and the evolved CO 2 remains entrapped in the clay increasing the level of intercalation and causing also some exfoliation. Then the morphology of the nanobiocomposite changes because of the processing conditions. Moreover, the thermomechanical degradation remarkably increased if the materials are not pre-dried because of the hydrolytic degradation of the biodegradable polyesters of the matrix.

Nanobiocomposites are a new class of biodegradable polymer materials with an ultrafine phase dispersion of the order of a few nanometers in a biodegradable polymer matrix that shows very interesting properties often very different from those of conventional filled polymers. In this work the morphology and the rheological and mechanical properties of a new nanobiocomposite made of a biodegradable copolyester based blend with an organomodified montmorillonite have been investigated to evaluate its possible use in several applications. SAXS diffractograms and TEM micrographs show that the in both the adopted processing conditions an hybrid intercalated/exfoliated morphology is observed. Rheological behavior is significantly influenced by the presence of the filler and more important, depends on the type of the applied type of flow. As for the mechanical properties, the elastic modulus strongly increases, while the elongation at break remarkably decreases.

No-tillage (NT) has been considered an agronomic tool to sequester soil organic carbon (SOC) and match the 4p1000 initiative requirements of conservative soil management. Recently, some doubts have emerged about the NT effect on SOC sequestration, often because observations and experimental data vary widely depending on climate and geographic characteristics. Therefore, a suitable SOC accounting method is needed that considers climate and morphology interactions. In this study, the yearly ratio between SOC in NT and conventional tillage (CT) (RRNT/CT) collected in a previous study for flat (96 samples) and sloping (44 samples) paired sites was used to map the overestimation of SOC sequestration. It was assumed that there would be an overestimation of NT capacity in sloping fields due to lower erosion processes with respect to CT. Towards this aim, Geographical Information System (GIS) techniques and an extensive input database of high spatial resolution maps were used in a simplified procedure to assess the overestimation of SOC stocks due to the sloping conditions and spatial variability of the Aridity Index (AI). Moreover, this also made it possible to quantify the effects of adopting NT practices on soil carbon sequestration compared to CT practices. The method was applied to the arable lands of five Mediterranean countries (France, Greece, Italy, Portugal and Spain) ranging between the 35° and 46° latitude. The results showed an overestimation of SOC sequestration, when the AI and soil erosion were considered. The average overestimation rate in the studied Mediterranean areas was 0.11 Mg ha−1 yr−1. Carbon stock overestimation ranged from 34 to 1417 Gg for Portugal and Italy, respectively. Even if overestimation is considered, 4p1000 goals are often reached, especially in the more arid areas. The findings of this research allowed us to map the areas suitable to meet the 4p1000 that could be achieved by adopting conservative practices such as NT.

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