A novel approach to design sustainable fiber reinforced materials from renewable sources: mathematical modeling for the evaluation of the effect of fiber content on biocomposite properties

Abstract The paper reports a sustainable, fast and efficient methodology to treat natural hemp fibers (HF) using a mechanochemical approach. Mechanical milling was used to carry out an alkaline attack on HFs for 30 minutes at ambient temperature. Composites HF/pectins were prepared by varying the fiber weight fraction (3%; 7.5%; 10%; 20% w/w by weight). The improvement in thermal degradation, mechanical and barrier properties to water vapor was correlated with the fiber volume fraction and mainly due to the improved fiber-matrix adhesion. The fibers-matrix interaction was then evaluated by analyzing and modeling the mechanical properties using several mathematical models: a modified Nielsen and Pukanszky and Smith models. Sorption isotherms to water vapor were analyzed through a modified Guggenheim, Anderson, de Boer (GAB) model where a new parameter, α, was introduced to consider the heterogeneity of the system. Finally, a modified Burgemman model was used to fit the experimental data and support the improvement in water diffusion with fiber loading

Comparison of the Peel-Associated Epiphytic Bacteria of Anthocyanin-Rich “Sun Black” and Wild-Type Tomatoes under Organic and Conventional Farming

Tomatoes are among the most consumed vegetables worldwide and represent a source of health-beneficial substances. Our study represents the first investigating the peel-associated epiphytic bacteria of red and purple (anthocyanin-rich) tomatoes subjected to organic and conventional farming systems. Proteobacteria was the dominant phylum (relative abundances 79–91%) in all experimental conditions. Enterobacteriaceae represented a large fraction (39.3–47.5%) of the communities, with Buttiauxella and Atlantibacter as the most represented genera. The core microbiota was composed of 59 operational taxonomic units (OTUs), including the majority of the most abundant ones. The occurrence of the most abundant OTUs differed among the experimental conditions. OTU 1 (Buttiauxella), OTU 2 (Enterobacteriales), and OTU 6 (Bacillales) were higher in red and purple tomatoes grown under organic farming. OTU 5 (Acinetobacter) had the highest abundance in red tomatoes subjected to organic farming. OTU 3 (Atlantibacter) was among the major OTUs in red tomatoes under both farming conditions. OTU 7 (Clavibacter) and OTU 8 (Enterobacteriaceae) had abundances 1% only in red tomatoes grown under conventional farming. PCA and clustering analysis highlighted a high similarity between the bacterial communities of red and purple tomatoes grown under organic farming. Furthermore, the bacterial communities of purple tomatoes grown under organic farming showed the lowest diversity and evenness. This work paves the way to understand the role of nutritional superior tomato genotypes, combined with organic farming, to modulate the presence of beneficial/harmful bacteria and supply healthier foods within a sustainable agriculture.Filas project MIGLIOR

Coaxial electrospun membranes of poly(ε-caprolactone)/poly(lactic acid) with reverse core-shell structures loaded with curcumin as tunable drug delivery systems

AbstractNano fibrous membranes core‐shell of poly(lactic acid) (PLA) and poly(ε‐caprolactone) (PCL), encapsulating 1 wt% of curcumin, are fabricated by coaxial electrospinning technique. Morphology and physical properties, as well as the release of curcumin, are studied and compared with neat PLA and PCL individually spinned. Morphological analysis shows for all the samples the obtainment of fiber oriented in random way, without defect and with a narrow distribution of the fiber dimensions (344 nm for PCL fibers and 450 nm for PLA fibers). Mechanical performances and barrier properties are evaluated on all membranes and found to be dependent on the fibers' composition and morphology. Water contact angle for all membranes is found higher than 90° (from 103° for PLA‐Curc to 128° for PCL‐Curc), expected since the hydrophobic behavior of the micro/nano electrospun morphology. The curcumin release from the coaxial fibers, modeled with a modified Weibull equation, shows the possibility of a fine tuning of drug release (up to 15 days) for the produced materials, depending on the required application

Preparation, processing and analysis of physical properties of calcium ferrite-CNTs/PET nano-composite

The present work is focused on the preparation of composites based on Poly(ethylene terephthalate) (PET) and novel nano-hybrid filler composed of Calcium Ferrite (CF)-Carbon Nanotubes (CNTs), obtained by direct growth of CNTs on CF based iron catalysts. The carbon content in the hybrid filler was 76 wt%. Composites loaded with 1.0, 1.5, 2.0, 3.0 wt% of filler were obtained by melt compounding and processed by thin-wall injection molding. Unfilled Poly(ethylene terephthalate) was processed using the same techniques. Structural characterization and physical properties (thermal, mechanical and electrical) were analyzed and correlated to the hybrid filler loading, and to the percentage of carbon nanotubes

Corrosion protection mechanisms of carbon steel by an epoxy resin containing indole-3 butyric acid modified clay

This work is an extension of studies into the mechanisms of corrosion protection of mild steel by an epoxy resin containing organically modified clay (Hang et al. [1]; Truc et al. [2]). In a previous study (Truc et al. [2]), it was shown that indole-3 butyric acid (IBA)-modified clay improved the corrosion performance of epoxy. In the present study, it was shown that the IBA is an anodic inhibitor and its efficiency was about 93%. Exfoliation and dispersion of the IBA-modified clay in the epoxy coating were checked by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The improvement of the corrosion performance of the epoxy coating containing IBA-modified clay by comparison with pure epoxy coating was confirmed for a low film thickness (10 μm). Local electrochemical impedance measurements performed on scratched samples revealed the inhibitive action of IBA at the carbon steel/coating interface. It was shown that the inhibitor release from the IBA-modified clay was favoured for high pH values. Thus, in neutral media, the corrosion process which induces a local increase of pH will increase the self-healing performance

Persistence of Enterobacteriaceae Drawn into a Marine Saltern (Saline di Tarquinia, Italy) from the Adjacent Coastal Zone

Enterobacteriaceae is present in various niches worldwide (i.e., the gastrointestinal tracts of animals, clinical specimens, and diverse environments) and hosts some well-known pathogens (i.e., salmonellas, shigellas and pathogenic coliforms). No investigation has focused on its occurrence in marine salterns, and it is not clear if these hypersaline environments could be a reservoir for these bacteria including some potentially harmful members. In this study, a two-year metabarcoding survey was carried out on samples collected from different ponds of the “Saline di Tarquinia” salterns and the nearby coastal waters. Enterobacteriaceae was recorded almost constantly in the seawaters feeding the saltern. Its abundance was generally higher in the sea than in the ponds, probably due to the higher anthropic impact. The same trend was evidenced for the key genus (Escherichia/Shigella) and OTU (OTU 5) of the Enterobacteriaceae community. Various parameters affected taxon/OTU abundance: Enterobacteriaceae, Escherichia/Shigella and OTU5 decreased with increasing salinity and rains; moreover, Escherichia/Shigella and OTU 5 were higher in autumn than in spring. Although Enterobacteriaceae did not seem to find the most favourable conditions for a high-abundance persistence in the saltern environment, it did not disappear. These observations suggested this environment as a potential reservoir for bacteria with possible important health implications