Photo-oxidative and soil burial degradation of irrigation tubes based on biodegradable polymer blends

Irrigation tubes based on biodegradable polymers were prepared via an extrusion-drawing process by Irritec and compared to conventional pipes made of high-density polyethylene (HDPE). A commercial polylactide/poly (butyleneadipate-co-butyleneterephthalate) (PLA/PBAT) blend (Bio-Flex®) and Mater-Bi® were used. The polymers were characterized from rheological and mechanical points of view. Irrigation pipes were subjected to photoaging with continued exposure to UV radiation up to 22 days. The degradability in the soil of irrigation tube samples was studied. The influence of temperature and UV irradiation on soil burial degradation was investigated. A soil burial degradation test was carried out at 30 °C and 50 °C for up to 70 days. The degree of degradation was evaluated from the weight loss percentage. The degradation rate of irrigation tube samples based on Mater-Bi® was higher at 30 °C and was stimulated after 14 days of UV irradiation. Higher temperatures or UV aging encouraged the disintegration in soil of Bio-Flex®-based irrigation tubes. Furthermore, tube samples, before and after UV and soil burial degradation, were analyzed by Attenuated Total Reflection-Fourier Transform Infra-Red (ATR-FTIR) spectroscop

Primi casi di naturalizzazione del noce nero (Juglans nigra L.) (Juglandaceae) in Sicilia

Il presente studio riporta i primi casi di naturalizzazione del noce nero in Sicilia. Il possibile ruolo giocato dagli animali disseminatori e dalle condizioni climatiche locali sono stati discussi

New and little known Cerambycidae (Coleoptera Chrysomeloidea) from Pantelleria Island (Sicily Channel, Italy)

Cerambycidae (Coleoptera Chrysomeloidea) nuovi e poco conosciuti dell’isola di Pantelleria (Cana-le di Sicilia, Italia).In questa nota riportiamo nuovi dati di due specie di Cerambycidae raccolte sul-l’isola di Pantelleria (Canale di Sicilia, Italia). In particolare, la presenza di Trichoferus holosericeus(Rossi, 1790) è confermata e Cephalocrius syriacus(Reitter, 1895) è riportato come nuovo recor

Variazione degli stock di carbonio del suolo in seguito ai processi di abbandono dei coltivi: il caso studio dell\u2019isola di Pantelleria (TP)

The recent abandonment of marginal agricultural areas in the Mediterranean has caused an increase of the surface occupied by pre-forest and forest formations. In order to study the carbon accumulation processes on Pantelleria Island was selected a North-facing area. This area includes 5 stages of succession (sds) that compose a chronosequence (from 0 to 30 years) to understand soil C accumulation processes after abandonment. These are abandoned vineyards or caperbushes, not disturbed (grazing, fire) since agricultural abandonment, and they are situated in thermomediterranean belt and on the same parent material and consequently considered in the same ecological conditions. Samples at 1 cm, 10 cm and 40 cm depth, respectively, were taken for every sds in three different soil relief areas. Litter samples were taken too. Organic carbon content was determined for every sample. Carbon content increases from a sds to the next one. There is a duplication of C from sds0 (cultivated field) to sd1 (abandoned since few years) and from sds4 (abandoned since 16-30 years) to sds5 (abandoned since > 30 years). It seems that different types of vegetation play a key-role in soil C dynamics and there are 85 t C ha-1 in the top 40 cm of the soil after 30 years from the abandonment in the chronosequence and an annual C sequestration rate equal to 3.4 t ha-1. These results show that revegetation offers good opportunities to sequestrate CO2 from the atmosphere and, therefore, to mitigate the greenhouse effect as it is requested by international agreements

Influence of Branching on the Rheology, Filmability and Mechanical and Optical Properties of a Biodegradable and Compostable Co-Polyester

Over the last years, bio-based and biodegradable alternatives have gained considerable attention both of academic and of packaging industrial communities, driven by recent legislation and increasing awareness concerning environmental issues related to traditional plastic. However, it is often observed that packaging products made from bioplastics do not exhibit comparable performance to those produced using common non-biodegradable ones. The presence of long chain branching improves the processing behavior under elongational flow and, then, the filmability of low viscosity polymers such as polyesters. In this work it has been demonstrated that the presence of long chain branching in a bio-co-polyester, induced by the use of pentaerythritol in the synthesis a of poly(butylene adipate-co-butylene terephthalate), is able to dramatically change the rheological behavior of the linear chain polyester improving its filmability. The addition of branching lead to an increase of the elastic modulus and the tensile strength in branched polyester films if compared to the linear ones, while the elongation at break decreased. This is due to the answer of the branched polyester to the non-isothermal elongational flow that allows a better orientation of the macromolecules of the branched polyester. The film obtained with the branched polyester showed a decrease in clarity and a slight increase in haze if compared to linear one due to differences in the morphology of the two samples

La struttura spaziale della successione secondaria delle piante legnose in un pascolo mediterraneo

Negli ultimi decenni molte aree agricole e pastorali dell’Europa e del Mediterraneo sono state abbandonate o hanno subito importanti cambiamenti nell'intensità dell'uso antropico, determinando processi di successione secondaria a volte anche rapidi dopo secoli di attività agricola determinando in alcuni casi un forte cambiamento nelle proporzioni tra aree agricole e aree forestali in molti paesi tra cui l’Italia. Nonostante molti studi abbiano descritto gli aspetti fitosociologici e strutturali di questa successione secondaria in diverse aree del Mediterraneo, la maggior parte di questi studi sono stati condotti su larga scala, con pochi dati disponibili riguardo alla struttura spaziale sviluppata lungo questa successione, specialmente attraverso una scala temporale. Tale caratterizzazione spaziale è molto rilevante per la migliore comprensione delle dinamiche della vegetazione, nonché per migliorare l'efficienza delle azioni selvicolturali da mettere in atto per guidare dove necessario questi processi. In questo studio abbiamo quantificato l'espansione della vegetazione a livello locale e a scala comprensoriale e caratterizzato la struttura spaziale di questa espansione in un arco di tempo di 24 anni in un pascolo tra i boschi all'interno della Riserva Naturale di Ficuzza (Palermo, PA), un'area protetta comprendente uno dei più importanti complessi forestali della Sicilia occidentale. Per raggiungere gli obiettivi abbiamo delimitato tre aree di saggio di 10 ettari ciascuna in cui la copertura della vegetazione legnosa è stata misurata e delimitata in ambiente GIS combinando classificazioni automatiche basate su pixel e fotointerpretazione. Abbiamo utilizzato immagini satellitari recenti ad alta risoluzione per valutare la copertura corrente e le fotografie aeree per valutare la copertura precedente. Tutta la vegetazione legnosa, macchie grandi e piccole così come alberi e arbusti isolati sono stati digitalizzati, verificati sul campo e classificati. La struttura spaziale dell'espansione della vegetazione è stata analizzata con l'analisi spaziale per indice di distanza (SADIE). In totale, la copertura della vegetazione legnosa naturale è aumentata del 68% lungo i 24 anni rivelando altresì la complessità dei processi di successione secondaria. Sorprendentemente, nonostante la forte espansione, la struttura spaziale aggregata della vegetazione non ha subito variazioni significative, con una correlazione spaziale globale e locale molto elevata, comprendendo sia aree a ridotto aumento di copertura che aree ad elevato aumento di copertura. I nostri risultati possono contribuire a valutare: (i) le dinamiche in corso; (ii) a prevedere quali sono le dinamiche che bloccano i processi di successione secondaria a determinati stadi (ad esempio formazioni pure di Prunus spinosa); (iii) quale è il ruolo delle piante madri; (iv) quale è il ruolo dei vettori (uccelli e mammiferi). Sono tutte questioni chiave per la conservazione della biodiversità e per la selvicoltura. Inoltre, i nostri risultati hanno rivelato delle differenze tra le aree che presentano una forte espansione di copertura e aree ancora prive di rigenerazione a volte anche dopo decenni. Tali risultati consentono di delimitare ad esempio le aree in cui è richiesto uno sforzo maggiore negli interventi attivi e quelle aree in cui la rigenerazione naturale è sufficiente per migliorare la copertura. Naturalmente vanno compiute delle valutazioni di altro tipo (sociali ed economiche nonché sulla biodiversità) perché alcune aree potrebbero essere gestite per preservare i pascoli

The effects of nanoclay on the mechanical properties, carvacrol release and degradation of a pla/pbat blend

The formulation of polymeric films endowed with the abilities of controlled release of antimicrobials and biodegradability is the latest trend of food packaging. Biodegradable polymer (Bio-Flex)-based nanocomposites containing carvacrol as an antimicrobial agent, and a nanoclay as a filler, were processed into blown films. The presence of such hybrid loading, while not affecting the overall filmability of the neat matrix, led to enhanced mechanical properties, with relative increments up to +70% and +200% in terms of elastic modulus and elongation at break. FTIR/ATR analysis and release tests pointed out that the presence of nanoclay allowed higher carvacrol loading efficiency, reasonably hindering its volatilization during processing. Furthermore, it also mitigated the burst delivery, thereby enabling a more controlled release of the antimicrobial agent. The results of mass loss tests indicated that all the formulations showed a rather fast degradation with mass losses ranging from 37.5% to 57.5% after 876 h. The presence of clay and carvacrol accelerated the mass loss rate of Bio-Flex, especially when added simultaneously, thus indicating an increased biodegradability. Such ternary systems could be, therefore, particularly suitable as green materials for food packaging applications, and for antimicrobial wrapping applications

Preliminary evaluation of plasmix compound from plastics packaging waste for reuse in bituminous pavements

Finding an appropriate technical solution for reusing waste plastics is crucial for creating a circular plastic economy. Although mechanical recycling is the best option for recycling post-consumer plastics, some heterogeneous mixed plastics cannot be recycled to produce secondary material due to their very low properties. In this case, alternative routes should be considered in order to limit their disposal as much as possible. Therefore, in order to solve the environmental problems in the landfills of plastic waste recycling, and to improve the mechanical performance of bitumen for road pavement, the reuse of these post-consumer plastic wastes are preliminarily evaluated for the modification of bitumen for road use. The field of polymers used so far and widely studied concerns virgin materials, or highly homogeneous materials, in case of recycled plastics. In this work, a highly heterogeneous mixed plastic—Plasmix—from the separate collection in Italy, is used as a bitumen modifier for road construction. The research focused on the dry (into the mixture) and wet (into the binder) addition of different content of the Plasmix compound, with the aim of assessing the feasibility of the modification itself. Results of the mechanical tests carried out prove an increase in performance and that there is a potential of the addition of the Plasmix compound both for binder and mixture modifications

Chemical composition of essential oils from Pantelleria Island autochthonous and naturalized spices and evaluation of their individual and combined antimicrobial activities

In this study, the antimicrobial activity of the essential oils (EOs) from Origanum majorana L. and Rosmarinus officinalis L. growing in Pantelleria (Sicily, Italy) were tested alone and in combination against some prokaryotic and eukaryotic food-borne pathogens. The chemical composition of the EOs as well as the minimum inhibitory concentrations (MIC) against the most sensitive strains were also determined. Both EOs showed interesting antimicrobial effects against all bacteria and yeasts tested. MIC was in the range 1.25-2.50 mu l/ml. Interestingly, O. majorana was particularly rich in thymol acetate, while carvacrol was present at very low percentages. Also R. officinalis EOs composition was different from rosemary collected in different areas, as being particularly rich in caryophyllene. Furthermore, the antimicrobial activity of the combination of O. majorana and R. officinalis EOs indicated their potential as food biopreservatives