Search

In the field of regenerative medicine, acrylated epoxidized vegetable oils are emerging as a promising avenue of exploration. The aim of this study is to evaluate the degradability of two formulations of acrylated epoxidized soybean oil (AESO): pure AESO and AESO diluted with soybean oil (SO) for potential bioprintability applications. The comprehensive investigation of these two polymeric formulations included optimization of polymerization conditions, confirmation of cytocompatibility, and, most importantly, the study of their degradability. The results reveal that AESO, used as a biomaterial for biomedical applications, undergoes a distinctive degradation process, combining both enzymatic and oxidative degradation (AESO/SO samples lose 29.45% of their weight after 60 days). This phenomenon is the result of a complex interplay of factors, including the chemical composition and physical characteristics of the polymer, the unique tissue environment in which it is implanted, and the duration of implantation. [ABSTRACT FROM AUTHOR]

In this paper two waste fillers, namely ground tire rubber (GTR) and coffee silverskin (CSS, a waste bio‐product from the coffee‐making process), have been used to produce sustainable ethylene‐propylene‐diene monomer (EPDM) rubber compounds vulcanized on steel sheets to fabricate rubber‐to‐steel bonded systems for industrial roofing applications. The compounds have shown good mechanical performances, with elastic moduli in the range of 13–16 MPa, tensile strength of 13–20 MPa and elongation at break >400%, and strong adhesion to the metal substrate. Moreover, the rubber‐to‐steel bonded systems present good sound insulation properties (mean sound transmission loss [STL] of 39 dB and noise level reduction in simulated hailstones impact tests of 62 dB with respect to bare steel 73 dB). Accelerated UV‐ and thermal‐aging tests have shown excellent adhesion of the compounds to the metal substrate with the CSS acting as an antioxidant agent preventing excessive polymer degradation. The selected waste‐derived materials result in promising fillers for more sustainable rubber compounds. Highlights: Waste fillers were used to produce sustainable rubber compounds.Rubber‐to‐steel bonded systems for roofing applications were produced.Rubber‐to‐steel bonded systems have good sound insulation properties.Rubber‐to‐steel bonded systems have excellent adhesion.Coffee silverskin filler acts as an antioxidant agent. [ABSTRACT FROM AUTHOR]

Nanoenergetics are defined as a class of nanomaterials that possess the ability to release energy in certain situations. These properties have been studied and deepened in recent years, so much so that nanoenergetics have been introduced into the use of the weapons industry, among others. It is therefore an emerging reality that deserves attention with regard to potential harmful effects on human and environmental health. it has been suggested that nanoenergetics may have genotoxic and immunotoxic effects, among others. Problems related to exposure to nanonenergetics can therefore potentially affect both exposed workers (both in the production and use phase) and the civilian population, if used in war scenarios, for example,. Starting from these assumptions, the INNOTOX research project aims to contribute to the in-depth study of the toxicity of nanonenergetics, through an integrated approach involving experts in occupational and forensic medicine, nanotoxicology and bioengineering. [ABSTRACT FROM AUTHOR]

The use of non-lethal weapons has spread worldwide, being introduced as an alternative to firearms in many countries such as the United States or the United Kingdom. Among non-lethal weapons, conducted electrical weapons have been adopted worldwide, to control unruly suspected criminals or to neutralise violent situations. The stun gun belongs to this category and is the most widely available, with more than 140,000 units in use by police officers in the field in the US, and an additional 100,000 electrical stun guns owned by civilians worldwide. In Italy, the use of conducted electrical weapons by law enforcement has only recently been introduced, with private use and commercialisation still prohibited, mainly due to controversies related to the potential dangers of such devices. Before the official adoption, several experiments had to be carried out, with mechanisms that reproduced the ballistics of the stun gun. Here we present the case of a man who suffered a self-injury trauma to his hand during a ballistics exercise with a crossbow loaded with stun gun probes. [ABSTRACT FROM AUTHOR]

This work is part of a research project aimed at developing a bio-based binder, composed mainly of polylactic acid (PLA), to produce Ti6Al4V feedstock suitable for use in MAM (Metal Additive Manufacturing) via mFFF (metal Fused Filament Fabrication), in order to manufacture a titanium alloy specimen. While in Bragaglia et al. the mechanical characteristics of this sample were analyzed, the aim used of this study is to compare the mentioned mFFF process with one of the most used MAM processes in aerospace applications, known as Selective Laser Sintering (SLS), based on the Life Cycle Assessment (LCA) method. Despite the excellent properties of the products manufactured via SLS, this 3D printing technology involves high upfront capital costs while mFFF is a cheaper process. Moreover, the mFFF process has the advantage of potentially being exported for production in microgravity or weightless environments for in-space use. Nevertheless, most scientific literature shows comparisons of the Fused Filament Fabrication (FFF) printing stage with other AM technologies, and there are no comparative LCA "Candle to Gate" studies with mFFF processes to manufacture the same metal sample. Therefore, both MAM processes are analyzed with the LCA "Candle to Gate" method, from the extraction of raw materials to the production of the finished titanium alloy sample. The main results demonstrate a higher impact (+50%) process for mFFF and higher electrical energy consumption (7.31 kWh) compared to SLS (0.32 kWh). After power consumption, the use of titanium becomes the main contributor of Global Warming Potential (GWP) and Abiotic Depletion Potential (ADP) for both processes. Finally, an alternative scenario is evaluated in which the electrical energy is exclusively generated through photovoltaics. In this case, the results show how the mFFF process develops a more sustainable outcome than SLS. [ABSTRACT FROM AUTHOR]

In this paper self-sensing nanocomposite formulations made of acrylonitrile butadiene styrene and different loading (3, 5 and 10 wt%) of multi-walled carbon nanotubes have been produced and 3D printed via fused filament fabrication. The nanocomposites have been characterized from a rheological, mechanical, thermal and electrical point of view to assess the strain-sensing properties. All the samples show a piezoresistive behaviour and the electrical resistance changes when a stress is applied. The gauge factor, measure of the sensitivity, for ABS 3CNT, ABS 5CNT and ABS 10CNT are 11.36, 3.21 and 1.62, respectively. The ABS 3CNT samples have shown the best self-sensing performances with high sensitivity and this formulation has been used for producing a health-monitoring 3D-printed smart structure where the active material is placed locally in the structure. The 3D-printed structure itself is able to monitor the strain and hence the stress level to which is subjected with a gauge factor of 1.5. A finite element analysis helps to explain the reason for reduced sensitivity namely the placement of the sensing layer. [ABSTRACT FROM AUTHOR]

Boron nitride nano-platelets have been functionalized with oleylamine using a simple method without ultrasonication. The functionalization is effective with the formation of a coordination bonds between the boron nitride nano-platelets and the oleylamine molecules. The oleylamine functionalization allows for the production of 25% by weight loaded polyamide 6 – boron nitride composites having higher mechanical properties (15% tensile strength increase) and better through-plane thermal conductivity (0.85 to 0.99 W/m·K) with respect to the untreated samples. A better particle-matrix interaction is confirmed by SEM imaging and rheological analysis. The injection moulding process determines a filler orientation which influences the thermal conductivity. Graphical Abstract [ABSTRACT FROM AUTHOR]

Sol-gel alumina coatings have been deposited on neodymium-iron-boron magnets for corrosion protection. The coatings present a compact amorphous structure due to the low thermal treatment (500 °C) with a thickness ranging from 0.8 to 2 microns, a Vickers hardness of 10 GPa and good adhesion to the substrate, measured by scratch test, with a failure mode of tensile cracking and chipping. The coatings are effective in protecting the NdFeB magnets from corrosion with reduction of current density (i.e. 2.07 × 10−6 A/cm2 for 2dip sample) of one order of magnitude with respect to the neat sample (1.15 × 10−5 A/cm2). [ABSTRACT FROM AUTHOR]

In this paper, poly-ether-ether-ketone (PEEK) carbon-nanotube (CNT) self-monitoring composites at different levels of filler loading (i.e., 3, 5 and 10% by weight) have been extruded as 3D-printable filaments, showing gauge factor values of 14.5, 3.36 and 1.99, respectively. CNT composite filaments of 3 and 5 wt% were 3D-printed into tensile samples, while the PEEK 10CNT filament was found to be barely printable. The 3D-printed PEEK 3CNT and PEEK 5CNT composites presented piezo-resistive behavior, with an increase in electrical resistance under mechanical stress, and showed an average gauge factor of 4.46 and 2.03, respectively. Mechanical tests highlighted that 3D-printed samples have a laminate-like behavior, presenting ultimate tensile strength that is always higher than 60 MPa, hence they offer the possibility to detect damages in an orthogonal direction to the applied load wit high sensitivity. [ABSTRACT FROM AUTHOR]

This work focuses on the replacement of mineral oils with bio-based waste cooking oils in rubber compounding. Two different waste cooking oils from potatoes and chicken frying process were analyzed by means of chemical and rheological tests to evaluate the chemical composition, the oxidative stability and the viscosity. Waste oils have been introduced in elastomeric compounds as substitute for typical processing aids (i.e. lubricants). Cure kinetics of rubber compounds was studied by rheological characterization. Mechanical properties of vulcanized samples were determined by means of tensile tests, hardness tests and dynamic mechanical analysis. The waste oils showed a rheological behavior very similar to the mineral oils conventionally employed in rubber manufacturing leading to almost the same processability of the resulting compound. The waste oils did not significantly affect the vulcanization kinetics of the rubber compound, as expected for conventional lubricants. Waste cooking oils and mineral oil show analogous influence on mechanical properties of cured compounds. At increasing oil content, the elongation at break and the tensile strength increased whereas the values of Elastic Modulus at 100% strain, the Storage Modulus and Shore A Hardness decreased with respect to the oil-free sample. These results are very promising, confirming the possibility to replace the mineral oils, in a good practice of circular economy. [ABSTRACT FROM AUTHOR]

The corrosion resistance features of two different Metal Matrix Composites based on 6061 and 2618 aluminium alloys reinforced by 20% Al2O3 particles by stir casting process, were studied in 3.5% NaCl and compared. The composites and their respective base alloys were characterised in terms of microstructure by optical and scanning electron microscopy and in terms of corrosion resistance by polarisation curves and electrochemical impedance. Results show how the presence of Al2O3 has different effects depending on matrix composition. In 6061 MMC, Al2O3 promotes the formation of Mg2Si which has a cathodic behaviour altering the pitting susceptibility of the composite. In 2618 MMC, the high content of Cu induces a strong uniform attack. The subsequent increase in the Open Circuit Potential caused a pitting attack. [ABSTRACT FROM AUTHOR]

Highlights The increasing production of plastics and its resulting environmental problems and waste management issues have prompted stakeholders and communities to focus on reducing, recycling, and reusing plastic products at the industrial level. While many important initiatives have been launched with a circular economy perspective, there is still a lack of research on the mechanical properties of various mixtures of recycled plastics. To address this research gap, the primary objective of this study is to present a parametric investigation on the homogenization of four different types of plastics: virgin polypropylene, recycled polypropylene, recycled high‐density polyethylene, and recycled low‐density polyethylene. The study aims to develop a homogenization methodology for multimaterial plastics reinforced with carbon nanotubes, focusing on their mechanical behavior, especially the Young's modulus. The second section of the research focuses on studying the Melt Flow Index (MFI) of various mixtures of recycled plastics. By analyzing the MFI, valuable insights can be gained regarding the flow characteristics and processability of these plastic blends. Finally, the research investigates the incorporation of nanoparticles into these novel polymers to enhance their mechanical properties, with a specific emphasis on addressing the reduction in Young's modulus caused by the utilization of recycled plastics. Overall, this study aims to contribute to the understanding of the mechanical behavior and processing characteristics of recycled plastic mixtures, as well as exploring potential strategies for improving their properties through the incorporation of nanoparticles. Mechanical and processing properties of Plastic blends are not studied yet. Proposing parametrical homogenization formulas to predict such properties. Mechanical properties obtained are low and not suitable for structural purposes Adding to the blend carbon nanotubes to increase their properties. Properties are increased up to 11 times for recycled plastics blend. [ABSTRACT FROM AUTHOR]

In this work, two types of chemical vapor deposition (CVD)-derived porous supporting materials consisting of CNTs-decorated diatomite (CNT/DE) and CNT sponges (CNS) were developed to prepare novel form-stable phase-change material (PCM) composites by impregnation, using polyethylene glycol (PEG) as the PCM. The CNT/DE support matrix showed highly entangled nanotubes (the weight ratio of CNTs to DE was 0.16) over and inside the porous structure of diatomite, giving the hybrid matrix an electrical response. The CNS that resulted was mainly composed of bent and interconnected CNTs forming a three-dimensional highly porous structure. XPS and FTIR results revealed that CNTs in both the supporting materials have a moderate amount of oxygen-containing functional groups. Both hosts allow for high PEG loading (about 75 wt%) without showing any PCM leakage during melting. Both form-stable PCM composites showed high thermal reliability upon a hundred melting-solidification DSC cycles (PEG/CNT/DE latent heat is 86 ± 4 J/g and PEG/CNS latent heat is 100 ± 2 J/g; melting temperature 34 °C). An analytical model was used to evaluate the passive cooling performance of the systems, simulating the thermal behaviour of a building wall containing the confined PCM in the hosts, resulting in a reduction in required cooling power of about 10%. The overall results suggest that the developed form-stable PCM composites could be considered promising additive materials for the production of building envelopes with thermal energy storage capability.