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

An additive model to predict the rheological and mechanical properties of polypropylene blends made by virgin and reprocessed components

In this work, an additive model for the prediction of the rheological and mechanical properties of monopolymer blends made by virgin and reprocessed components is proposed. A polypropylene sample has been reprocessed more times in an extruder and monopolymer blends have been prepared by simulating an industrial process. The scraps are exposed to regrinding and are melt reprocessed before mixing with the virgin polymer. The reprocessed polymer is, then, subjected to some thermomechanical degradation. Rheological and mechanical experimental data have been compared with the theoretical predictions. The results obtained showed that the values of this simple additive model are a very good fit for the experimental values of both rheological and mechanical properties

Qualità pomologica e sensoriale di 10 varietà di mango (Mangifera indica L.) coltivate in Sicilia

Il mango (Mangifera indica L.) è una pianta arborea originaria della regione Indo-Burmese, che appartiene botanicamente alla famiglia delle Anacardiaceae, principalmente coltivata nei paesi a clima tropicale e subtropicale ed oggi, complice il cambiamento climatico, diffusa anche nel bacino del mediterraneo. In Italia il mango viene coltivato solo in Sicilia dove areali della costiera tirrenica hanno fatto registrare produzioni di pregio e una crescente diffusione di nuove cultivar provenienti dai luoghi di origine. Limiti vegetazionali piuttosto stretti, soprattutto in termini di minime termiche stagionali, hanno, in passato, causato l’insuccesso di numerosi nuovi impianti basati sull’introduzione di varietà inedite negli areali a clima mediterraneo-subtropicale come in Sicilia. Per evitare il verificarsi di tali situazioni occorre, quindi, valutare con attenzione il comportamento vegeto-produttivo delle nuove introduzioni varietali. Il presente lavoro ha avuto come obiettivo quello di valutare l’adattamento di 10 cultivar di mango mettendo in relazione gli stadi fenologici con gli andamenti termici stagionali utilizzando la scala BBCH (Biologische Bundesantalt, Bundessortenamt und Chemische Industrie) e valutando la qualità fisico-chimica dei frutti. Per ciascun frutto delle 10 varietà in esame sono state analizzate le seguenti caratteristiche: peso del frutto, diametro trasversale del frutto, diametro longitudinale del frutto, consistenza della polpa, peso della polpa, peso della buccia, peso del seme, diametro trasversale del seme, diametro longitudinale del seme. Del succo di ogni frutto sono stati analizzati il contenuto in solidi solubili e l’acidità titolabile. Le prove sono state svolte presso l’azienda Cupitur sita in Caronia Marina, provincia di Messina. Le cv prese in esame sono state: Glenn, Osteen, Maya, Nam Dok Mai, Irwin, Calypso, Valencia Pride, Keitt, Kent e Tommt Atkyns. La correlazione tra stadi fenologici e temperatura nonché il confronto con i risultati ottenuti in ambienti vocati indicano che, seppur con alcuni limiti legati all’inverno, le aree della costa tirrenica della Sicilia, dove queste varietà sono state coltivate, risultano un ambiente climaticamente idoneo per il corretto evolversi delle fasi vegetative e produttive e l’ottenimento di frutti dalle interessanti qualità organolettiche. Tuttavia, l’analisi dei dati di questo ultimo anno ha evidenziato alcune problematiche in grado di influenzare negativamente lo sviluppo delle piante. Temperature al di sotto dei valori critici, infatti, ci obbligano all’uso di frangivento, per ridurre il rischio di esposizione a venti freddi, e al ricorso ad apprestamenti protettivi delle singole piante nei primi anni dell’impianto. Dalle analisi pomologiche risulta un’ampia variabilità delle caratteristiche fisico-chimiche in grado di offrire una ampia scelta commerciale. L’introduzione di queste nuove cultivar in Sicilia consentirebbe un ampliamento del calendario di maturazione da agosto fino a novembre, limitando il ricorso all’importazione, ma va ulteriormente approfondito in relazione ai fattori sopra esposti

A Green Approach for Recycling Compact Discs

Compact discs (CDs) and digital versatile discs (DVDs) are mainly made by polycarbonate disc, a thin layer of aluminum or silver, a thin layer of a coating and a thin layer of a label of paper or PET. The recycling of these discs is difficult due to the removal of these non-polymeric layers and to our best knowledge, no industrial plants have been resent for their recycling. In this work, we propose a facile way to remove the non-polymeric layers and investigate the effect of the repetitive extrusion process on the processability and on the mechanical properties of the recycled polycarbonate. A few works have been published dealing with both the removal of the non-polymeric layers and the mechanical recycling of the disk of polycarbonate. In our approach, the removal of the non-polymeric layers is easily obtained through a thermo-mechanical treatment in a basic solution by ammonia. This process can be considered green because is made at a low temperature with a small amount of water and a very small amount of ammonia, saving energy and water. The properties of the polycarbonate remain good if the mechanical recycling is made after drying the post-consumer polycarbonate

Investigation on the properties and on the photo-oxidation behaviour of polypropylene/fumed silica nanocomposites

This work investigates the effects of very small amounts of fumed silica on the morphology and on the rheological and mechanical behaviour of polypropylene nanocomposites and on their photo-oxidation behaviour. Polypropylene nanocomposites were prepared using a twin-screw corotating extruder with 0, 1 and 2 wt/wt% of SiO2. Morphological, mechanical, thermomechanical and rheological properties were examined. It was found that the viscosity of the matrix is reduced by the presence of the silica nanoparticles, suggesting a poor adhesion between the two phases and probably some lubricating effect. On the contrary, the mechanical and, in particular, the thermomechanical properties of the matrix are considerably improved by the presence of the silica. In particular, elastic modulus and tensile strength increases remarkably, and this effect becomes more and more remarkable with an increasing temperature. As for the photo-oxidation behaviour, the presence of silica improves the photostability of the polypropylene matrix. This effect has been attributed to both the barrier to the oxygen and to the absorbance of the UV radiation from the silica nanoparticles. Finally, no significant effect of the silica nanoparticles has been put in evidence on the crystallisation behaviour of the polypropylene. As for the effect of the silica content, the difference in the properties of the two nanocomposites is relatively small and all the measured properties depend much less than linearly with its amount. This has been correlated with the reaggregation of the nanoparticles that, having a larger size, decrease the contact area between the matrix and the filler

Toward the Decarbonization of Plastic: Monopolymer Blend of Virgin and Recycled Bio-Based, Biodegradable Polymer

Decarbonization of plastics is based on two main pillars: bio-based polymers and recycling. Mechanical recycling of biodegradable polymers could improve the social, economic and environmental impact of the use of these materials. In this regard, the aim of this study was to investigate whether concentrations of the same recycled biopolymer could significantly affect the rheological and mechanical properties of biodegradable monopolymer blends. Monopolymer blends are blends made of the same polymers, virgin and recycled. A sample of commercially available biodegradable blend was reprocessed in a single-screw extruder until two extrusion cycles were completed. These samples were exposed to grinding and melt reprocessed with 75% and 90% of the same virgin polymer. The blends were characterized by tensile tests and rheological tests. The results obtained showed that while multiple extrusions affected the mechanical and rheological properties of the polymer, the concentration of the reprocessed material present in the blends only very slightly affected the properties of the virgin material. In addition, the experimentally observed trends were accurately predicted by the additive model adopted

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

Mechanical and thermal properties of insulating sustainable mortars with ampelodesmos mauritanicus and pennisetum setaceum plants as aggregates

The use of natural fibers in cement composites is a widening research field as their application can enhance the mechanical and thermal behavior of cement mortars and limit their carbon footprint. In this paper, two different wild grasses, i.e., Ampelodesmos mauritanicus, also called diss, and Pennisetum setaceum, also known as crimson fountaingrass, are used as a source of natural aggregates for cement mortars. The main purpose is to assess the possibility of using the more invasive crimson fountaingrass in place of diss in cement-based vegetable concrete. The two plant fibers have been characterized by means of scanning electron microscopy (SEM), helium picnometry and thermogravimetric analysis. Moreover, the thermal conductivity of fiber panels has been measured. Mortars samples have been prepared using untreated, boiled and Polyethylene glycol 4000 (PEG) treated fibers. The mechanical characterization has been performed by means of three point bending and compression tests. Thermal conductivity and porosity have been measured to characterize physical modification induced by fibers’ treatments. The results showed better thermal and mechanical properties of diss fiber composites than fountaingrass one and that fiber treatments lead to a reduction of the thermal insulation propertie

Possibile origine e consistenza di un popolamento di Quercus trojana Webb subsp. trojana (Fagaceae) nel Bosco della Ficuzza (Palermo, Sicilia

Possible origin and demographic asset of a population of Quercus trojana Webb subsp. trojana (Fagaceae) in the wood of Ficuzza (Palermo, Sicily). The first record of Macedonian oak in Sicily is reported. The finding consists of 73 adult and 4 young individuals. A morphometric analysis of all of them, along with an assessment of their phytosanitary status was carried out. They all grow between 700 and 850 m a.s.l. on a 2,30 ha area, characterized by a land mosaic of shrubland and forest patches. Notwithstanding two years of researches, no ultimate proof has been found on their alien status. On this purpose, several alternative hypothesis are formulated and their strengths and weaknesses are discussed. Considering that the environmental conditions of Ficuzza fit very well the ecological requirements of Quercus trojana, even the native status of local population cannot be totally rejected. On the other hand, many data support its recent introduction. In fact, according to interviews to old forest workers, archive documents and aerial photos, most part of the trees of this area have been planted just few years after the end of the Second World War, and dendrochronological analyses have pointed out that the biggest Macedonian oaks of Sicily are no more than 50-60 years old. Whatever the origin of local Macedonian oak population is, the presence of natural renovation testifies, at least, its full naturalisation within the Sicilian territory

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