Aromatic hyperbranched polyester/RTM6 epoxy resin for EXTREME dynamic loading aeronautical applications

The effects of the addition of an aromatic hyperbranched polyester (AHBP) on thermal, mechanical, and fracture toughness properties of a thermosetting resin system were investigated. AHBP filler, synthesized by using a bulk poly-condensation reaction, reveals a glassy state at room temperature. Indeed, according to differential scanning calorimetry measurements, the glass transition temperature (Tg) of AHBP is 95 °C. Three different adduct weight percentages were employed to manufacture the AHBP/epoxy samples, respectively, 0.1, 1, and 5 wt%. Dynamical Mechanical Analysis tests revealed that the addition of AHBP induces a negligible variation in terms of conservative modulus, whereas a slight Tg reduction of about 4 °C was observed at 5 wt% of filler content. Fracture toughness results showed an improvement of both critical stress intensity factor (+18%) and critical strain energy release rate (+83%) by adding 5 wt% of AHBP compared to the neat epoxy matrix. Static and dynamic compression tests covering strain rates ranging from 0.0008 to 1000 s−1 revealed a pronounced strain rate sensitivity for all AHBP/epoxy systems. The AHBP composites all showed an increase of the true peak yield compressive strength with the best improvement associated with the sample with 0.1 wt% of AHBP

Fracture Toughening Mechanisms in Epoxy Adhesives

Fracture toughness is generally considered as the main properties of a polymer or a polymer adhesive system for measuring the material resistance to the extension of cracks. Epoxy adhesives are generally brittle in nature; however, the addition of a second dispersed phase could induce a remarkable increase of damage tolerance performance by an enhancement of the material fracture toughness. The fracture behavior of a filled epoxy resin is strongly affected by the dimensions, the shape, and the chemical nature of the considered filler. The chapter describes the different toughening mechanisms for polymer adhesives with special attention toward innovative nanofiller such as graphene nanoplatelets and hyperbranched polymer nanoparticles

Ethical approach and professional responsibility in workplace drug testing: An update on the eff ectiveness of the Italian current legislation

Introduction: The Italian legislation on workplace drug testing (WDT), applied to “at-risk workers” since October 2008, calls for mandatory procedures about screening tests on urine performed by occupational health specialists and confirmation tests by gas chromatography/mass spectrometry performed by forensic laboratories. Aim: Evaluating the impact of the current law on WDT on trends of drug use in workers and discuss some ethical implications and professional responsibility connected to the management of the toxicological controls. Materials and Methods: The toxicological analyses performed from 2001 to 2014 on 73,656 workers (aged between 19 and 65 years; 92% males and 8% females), mainly employed in transports were selected for the present study. Confirmation analysis has been requested on urine samples (n = 3934) previously identified as positive for one or more drugs by immunoassay screening tests for opiates, methadone, cannabinoids, cocaine, buprenorphine, amphetamines, and analogues. Results: Relevant differences were observed, both in the incidence and in the type of drugs used, before and after the mandatory law application. At screening the positive urine were n = 2455 during 2001-2008 and n = 1479 since 2009. Among those of this second period, only 14.6% were confirmed as true positive versus the 74% of urine confirmed during 2001-2008. Moreover, the polydrug use, since 2009, decrease from 32% to 8% of cases. Cannabis and cocaine were most frequently used, alone or together with other drugs. The use of opiates, methadone and amphetamines has been observed for <5% of the workers without significant differences before and after 2009. Conclusion: To explain the decrease of our epidemiological data, two factors were considered as the prevailing ones: The deterrent effect of the mandatory nature of the drug tests and the behavior often adopted by the occupational physicians in order to avoid professional liability or disputes by workers representatives. The ethical principles, that occupational health physicians and toxicologists need to employ, to avoid the violation of the workers’ rights were discussed

Effect of silica nanoparticles on the compressive behavior of RTM6 epoxy resin at different strain rates

RTM6 epoxy resin is considered the main matrix material for high performance aeronautical grade composites which can be subjected to impact loads. Research efforts have been spent to improve the strength and the overall impact properties of these resins. One of the routes followed focuses on the enhancement of the epoxy resin by the addition of rigid nanoparticles with different weight percentages and sizes. The purpose of this work is to study the compressive behavior of RTM6 epoxy resin filled with silica nanoparticles at different strain rates. Two types of epoxy resins, namely neat epoxy resin and epoxy resin filled with silica nanoparticles at 0.1% weight percentage were tested. Quasi-static experiments were performed at strain rates of 0.008, 0.08, and 0.8 /s , while high strain rate experiments were performed at strain rates approx. 1000 /s using the split Hopkinson pressure bar technique. The behavior of both the nanoparticle filled resin and neat resin is compared and discussed. The effect of the silica nanoparticles on the compressive yield strength is also presented

Potential contact and intraocular lenses based on hydrophilic/hydrophobic sulfonated syndiotactic polystyrene membranes

Abstract Crystalline films of syndiotactic polystyrene (s-PS), a commercially available thermoplastic polymer, having a highly hydrophilic amorphous phase, were achieved by using a mild solid-state sulfonation procedure. Despite the used mild process conditions, an easy and uniform sulfonation of the phenyl rings of the amorphous phase is obtained. The crystallinity of the polymer was not affect by the sulfonation degree (S), at least at S less than 20%, and the obtained polymer films show the nanoporous crystalline form of s-PS. As widely reported in literature, the nanoporous nature of the polymer crystalline phase gives to these materials the ability to absorb and release organic molecules of appropriate size and polarity. This property, coupled to transparency, makes these materials potentially useful intraocular lens (IOLs) and contact lens applications. Sulfonation procedure and sulfonated film samples characterization by using wide-angle X-ray diffraction (WAXD), Fourier-transform infrared (FTIR) and ultraviolet-visible (UV-vis) spectroscopy techniques and water sorption tests were reported. Furthermore, the biocompatibility study demonstrated no cytotoxicity and appropriate cell interaction properties for the specific applications

Cyclic moisture sorption and its effects on the thermomechanical properties of epoxy and epoxy/MWCNT nanocomposite

Funding Information: This research was funded by ERDF project No. 1.1.1.2/VIAA/1/16/066 for the support of the post-doctoral research project "Environmental effects on physical properties of smart composites and fiber-reinforced plastics modified by carbonaceous nanofillers for structural applications". Publisher Copyright: © 2019 by the authors.The aim of this work was to reveal the moisture absorption-desorption-resorption characteristics of epoxy and epoxy-based nanocomposites filled with different multiwall carbon nanotubes (MWCNTs) by investigating the reversibility of the moisture effect on their thermomechanical properties. Two types of MWCNTs with average diameters of 9.5 and 140 nm were used. For the neat epoxy and nanocomposite samples, the moisture absorption and resorption tests were performed in atmospheres with 47%, 73%, and 91% relative humidity at room temperature. Dynamic mechanical analysis was employed to evaluate the hygrothermal ageing effect for unconditioned and environmentally "aged" samples. It was found that moisture sorption was not fully reversible, and the extent of the irreversibility on thermomechanical properties was different for the epoxy and the nanocomposite. The addition of both types of MWCNTs to the epoxy resin reduced sorption characteristics for all sorption tests, improved the hygrothermal and reduced the swelling rate after the moisture absorption-desorption.publishersversionPeer reviewe

Fatal poisoning by ingestion of a self-prepared oleander leaf infusion

An unusual case of poisoning by the ingestion of oleander leaves is reported. A 71 year old male laboratory technician committed suicide at home in this unusual manner. At the death scene a steel pan and other paraphernalia, used for the extraction of oleandrin and other cardiac glycosides from the leaves of the Nerium oleander plant were found. Toxicological investigations for oleandrin, oleandrigenin, neritaloside, and odoroside were performed by LC–MS/MS on all biological samples (peripheral blood, vitreous humor, urine, liver, gastric contents) and on the yellow infusion found at the death scene. In all samples, toxic levels of oleandrin were detected (blood 37.5 ng/mL, vitreous humor 12.6 ng/mL, urine 83.8 ng/mL, liver 205 ng/mg, gastric content 31.2 μg/mL, infusion 38.5 μg/mL). Qualitative results for oleandrigenin, neritaloside, and odoroside were obtained. Oleandrigenin was present in all tissue samples whereas neritaloside and odoroside were absent in the blood and vitreous humor but present in urine, liver, gastric content, and in the leaf brew. The purpose of this study was the identification of oleandrin and its congener oleandrigenin, detected in the vitreous humor. The blood/vitreous humor ratio was also calculated in order to assess of the likely time interval from ingestion to death. According to the toxicological results death was attributed to fatal arrhythmia due to oleander intoxication. The manner of deathwas classified as suicide through the ingestion of the infusion

Fatal poisoning by ingestion of a self‑prepared oleander leaf infusion

An unusual case of poisoning by the ingestion of oleander leaves is reported. A 71 year old male laboratory technician committed suicide at home in this unusual manner. At the death scene a steel pan and other paraphernalia, used for the extraction of oleandrin and other cardiac glycosides from the leaves of the Nerium oleander plant were found. Toxicological investigations for oleandrin, oleandrigenin, neritaloside, and odoroside were performed by LC–MS/MS on all biological samples (peripheral blood, vitreous humor, urine, liver, gastric contents) and on the yellow infusion found at the death scene. In all samples, toxic levels of oleandrin were detected (blood 37.5 ng/mL, vitreous humor 12.6 ng/mL, urine 83.8 ng/mL, liver 205 ng/mg, gastric content 31.2 µg/mL, infusion 38.5 µg/mL). Qualitative results for oleandrigenin, neritaloside, and odoroside were obtained. Oleandrigenin was present in all tissue samples whereas neritaloside and odoroside were absent in the blood and vitreous humor but present in urine, liver, gastric content, and in the leaf brew. The purpose of this study was the identifcation of oleandrin and its congener oleandrigenin, detected in the vitreous humor. The blood/vitreous humor ratio was also calculated in order to assess of the likely time interval from ingestion to death. According to the toxicological results death was attributed to fatal arrhythmia due to oleander intoxication. The manner of death was classifed as suicide through the ingestion of the infusion

Hydrothermal Aging of an Epoxy Resin Filled with Carbon Nanofillers

The effects of temperature and moisture on flexural and thermomechanical properties of neat and filled epoxy with both multiwall carbon nanotubes (CNT), carbon nanofibers (CNF), and their hybrid components were investigated. Two regimes of environmental aging were applied: Water absorption at 70 °C until equilibrium moisture content and thermal heating at 70 °C for the same time period. Three-point bending and dynamic mechanical tests were carried out for all samples before and after conditioning. The property prediction model (PPM) was successfully applied for the prediction of the modulus of elasticity in bending of manufactured specimens subjected to both water absorption and thermal aging. It was experimentally confirmed that, due to addition of carbon nanofillers to the epoxy resin, the sorption, flexural, and thermomechanical characteristics were slightly improved compared to the neat system. Considering experimental and theoretical results, most of the epoxy composites filled with hybrid carbon nanofiller revealed the lowest effect of temperature and moisture on material properties, along with the lowest sorption characteristics

A five years study on drug-related deaths in Campania (Italy)

Objectives.The study regards n. 267 drug related deaths submitted to toxicological anal-yses for forensic purpose, since 2008 to 2012, at the Laboratory of Forensic Toxicology of the Second University of Napoli (SUN), Italy. Among the cases studied (94% males and 6% females) the 13.1% regards foreign citizens.Methods. For each case autopsy findings and all drugs detected were recorded. In addition other epidemiological data such as age, race, gender, place and circumstance of death were also supplied. A systematic toxicological analysis (STA) for illicit drug, other pharmaceuticals, new psychotropic substances and ethanol has been applied on the specimens collected at autopsy and all positive results were confirmed by a quan-titative analysis (GC/MS or LC-MS/MS).Results. Toxicological results shows that simultaneous use of multiple illicit drugs was responsible of the largest mortality rate (57.7%), in both males and females. In the poly-drug use the cocaine was the most detected substance. The association of heroin/cocaine was identified in the 22.5% of deaths. The finding of only one drug was cor-related with an opiate drug for the 14.2% and with cocaine for the 4.5% of cases. The distribution by age and gender demonstrates an increase in deaths among males aged over 30 years and among women older than 35 years. The territorial distribution of the deaths in the different surrounding areas and in the residential quarters of the Naples city demonstrates that the 76% of deaths occurred in a place different from the usual residence.Conclusion. Results obtained demonstrate that prevails, at present, the need to specifi-cally explore the changing patterns of poly-drug use among addicts, because studying the prevalence of mortality subsequent to the consumption of a single illicit drug may be insufficient to guide preventive policies in public health