Stability of proton exchange membranes in phosphate buffer for enzymatic fuel cell application: hydration, conductivity and mechanical properties

Proton-conducting ionomers are widespread materials for application in electrochemical energy storage devices. However, their properties depend strongly on operating conditions. In bio-fuel cells with a separator membrane, the swelling behavior as well as the conductivity need to be optimized with regard to the use of buffer solutions for the stability of the enzyme catalyst. This work presents a study of the hydrolytic stability, conductivity and mechanical behavior of different proton exchange membranes based on sulfonated poly(ether ether ketone) (SPEEK) and sulfonated poly(phenyl sulfone) (SPPSU) ionomers in phosphate buffer solution. The results show that the membrane stability can be adapted by changing the casting solvent (DMSO, water or ethanol) and procedures, including a crosslinking heat treatment, or by blending the two ionomers. A comparison with Nafion(TM) shows the different behavior of this ionomer versus SPEEK membranes

Congenital supravalvar mitral ring: An underestimated anomaly

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Anion-conducting polymer electrolyte without ether linkages and with ionic groups grafted on long side chains: Poly(Alkylene Biphenyl Butyltrimethyl Ammonium) (ABBA)

In thisworkwe report the synthesis of the newionomer poly(alkylene biphenyl butyltrimethyl ammonium) (ABBA) with a backbone devoid of alkaline-labile C-O-C bonds and with quaternary ammonium groups grafted on long side chains. The ionomer was achieved by metalation reaction with n-butyllithium of 2-bromobiphenyl, followed by the introduction of the long chain with 1,4-dibromobutane. The reaction steps were followed by 1H-NMR spectroscopy showing the characteristic signals of the Br-butyl chain and indicating the complete functionalization of the biphenyl moiety. The precursor was polycondensed with 1,1,1-trifluoroacetone and then quaternized using trimethylamine (TMA). After the acid catalyzed polycondensation, the stoichiometric ratio between the precursors was respected. The quaternization with TMA gave a final degree of amination of 0.83 in agreement with the thermogravimetric analysis and with the ion exchange capacity of 2.5 meq/g determined by acid–base titration. The new ionomer blended with poly(vinylalcohol) (PVA) or poly(vinylidene difluoride) (PVDF) was also characterized by water uptake (WU) and ionic conductivity measurements. The higher water uptake and ionic conductivity observed with the PVDF blend might be related to a better nanophase separation

Aliphatic anion exchange ionomers with long spacers and no ether links by Ziegler–Natta polymerization: properties and alkaline stability

In this work we report the synthesis of poly(vinylbenzylchloride-co-hexene) copolymer grafted with N,N-dimethylhexylammonium groups to study the effect of an aliphatic backbone without ether linkage on the ionomer properties. The copolymerization was achieved by the Ziegler– Natta method, employing the complex ZrCl4 (THF)2 as a catalyst. A certain degree of crosslinking with N,N,N0,N0-tetramethylethylenediamine (TEMED) was introduced with the aim of avoiding excessive swelling in water. The resulting anion exchange polymers were characterized by 1H-NMR, FTIR, TGA, and ion exchange capacity (IEC) measurements. The ionomers showed good alkaline stability; after 72 h of treatment in 2MKOH at 80 C the remaining IEC of 76% confirms that ionomers without ether bonds are less sensitive to a SN2 attack and suggests the possibility of their use as a binder in a fuel cell electrode formulation. The ionomers were also blended with polyvinyl alcohol (PVA) and crosslinked with glutaraldehyde. The water uptake of the blend membranes was around 110% at 25 C. The ionic conductivity at 25 C in the OH form was 29.5 mS/cm

Nanocomposite anion exchange membranes with a conductive semi-interpenetrating silica network

Nanocomposite anion exchange membranes were synthesized based on poly(sulfone trimethylammonium) chloride. A hybrid semi-interpenetrating silica network containing a large amount of quaternary ammonium groups was prepared by two sol–gel routes, in situ with a single precursor, N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride (TMSP), or ex situ mixing two precursors, TMSP and 3-(2-aminoethylamino)propyldimethoxy-methylsilane (AEAPS). The properties of these hybrid composites and their degradation after immersion in 1 M KOH at 60 °C were studied. The degradation is reduced in the composite materials with a lower decrease in the ion exchange capacity. FTIR spectra showed that a main degradation mechanism with a single precursor TMSP is the dissolution of the hybrid silica network in KOH, whereas it is stable with the mixture of TMSP/AEASP. This conclusion is in agreement with the thermogravimetric analysis. The mechanical properties show a better ductility with a single precursor and higher stiffness and strength, but less ductility, by the ex situ route. The activation energy was between 0.25 and 0.14 eV for Cl and OH ion conduction, respectively, consistent with the migration mechanism

The Language of Pain in the Hypermobile Ehlers–Danlos Syndrome: Metaphors as a Key to Understanding the Experience of Pain and as a Rehabilitation Tool

Ehlers-Danlos syndromes are a heterogeneous group of Heritable Connective Tissue Disorders characterized by joint hypermobility, skin hyperextensibility, and tissue fragility. Among the different types, the hypermobile Ehlers-Danlos syndrome is the most frequent and includes generalized joint hypermobility as the major diagnostic criterion. Joint hypermobility in hypermobile Ehlers-Danlos syndrome is often associated with pain that does not always allow the use of effective pain-reducing treatments. Patients with hEDS constantly describe their pain in detail. Eighty-nine patients with hEDS diagnoses were recruited and evaluated. They were asked to describe their pain in writing. The texts were examined through Linguistic Inquiry and Word Count. Correlational analyses were conducted between pain perception and language. A comparison of high/low pain perception and the quality of metaphors was carried out. The results showed that language quality varies depending on how much pain is perceived. The greater the pain is perceived, the lesser the positive effects and the greater the negative effects and dehumanizing metaphors are being used. Moreover, a greater pain seems to be related to a verbal experience of greater isolation and less self-care. In conclusion, the use of metaphors is a useful tool for examining illness experience and may help clinicians in the rehabilitation program

Sustainable exploitation of paper mill wastes: a resource to re-use in the paper factory

In the papermaking industry, billions of tonnes of paper mill wastes are globally produced as wastes every year. These include cellulosic and inorganic sludges, which are traditionally landfilled, leading to environmental and economic issues. For these reasons, it is urgent to develop new sustainable strategies to exploit these fractions. Up to now, these sludges have been exploited i) for land application (as soil amendment/substrate), ii) for energy recovery and iii) for the production of bio-composites. However, the above possibilities involve the direct use of the bulk wastes, without fractionating/exploiting each feedstock component. In the perspective of the valorisation of the different components, the present investigation has considered different strategies: i) a thermal treatment, ii) an alkaline and iii) a mechanical one, aimed at the fractionation and recovery of the two main components of cellulosic and inorganic sludge, cellulose and calcium carbonate, respectively, that could be advantageously reused within the same papermaking process

Recognition of facial emotion expressions and perceptual processes in 22q11.2 deletion syndrome

Background: Social cognition (SC) deficits and of its facial emotion expression (FEE) component have been described in 22q11.2 Deletion Syndrome (22q11.2DS), a high-risk for schizophrenia (SCZ) systemic genetic syndrome. Correlations between deficits in FEE skills and visual-spatial abilities in people with 22q11.2DS warrant investigation. Methods: The sample consisted of 37 patients with 22q11.2DS (DEL), 19 with 22q11.2DS and psychosis (DEL-SCZ), 23 with idiopathic SCZ, and 48 healthy controls. We assessed FEE through The Ekman 60 Faces test (EK-F60), visual-spatial skills with Raven's Standard Progressive Matrices, and symptom severity with the positive And negative syndrome scale. Statistics were conducted through multivariate analysis of variance and correlation analysis. Results: Patients with 22q11.2DS performed worse that the other groups in recognizing Surprise, Disgust, Rage, Fear, and Neutral expressions on the EK-F60. Recognition of Surprise and Disgust correlated positively with visual-spatial abilities in patients with 22q11.2DS; negative and cognitive symptoms correlated negatively with recognition of Sadness, Surprise, and Disgust. Conclusions: Patients with 22q11.2DS show impairments of both peripheral and central steps of the emotional recognition process, leading to SC deficits. The latter are present regardless of the presence of a full-blown psychosis