A novel route to polyimides via polyamic aryl amides

Summary A new synthetic route to polyimides was studied on monofunctional model compounds by the reaction of various 4-substituted phenyl-phthalisoimides with paratoluidine to form asymmetrically substituted diphthalamides followed by thermal cyclization to phthalimide. Both steps of the preparation pathway were kinetically explored. It was determined that the first step is governed by second order constants directly dependent upon the pK_a of the amine used to prepare the beginning isoimide as well as the regioselectivity of the last step.     

Social and clinical factors influencing the choice of coping strategies in relatives of patients with schizophrenia: results of the BIOMED I study

The impact of social and clinical factors on the choice of coping strategies of a sample of 236 relatives of patients with schizophrenia, living in five European countries, was explored using well-validated questionnaires. The adoption of problem-focused coping strategies was more frequent among young relatives and among relatives of younger patients, and was associated with higher levels of practical and emotional social support and of professional help. In contrast, emotion-focused strategies were more frequently adopted by relatives who had been living longer with the patient and who had poorer social support. It is suggested that supportive and educational interventions should be provided as early as possible to relatives of patients with schizophrenia, which, in addition to having a practical focus, should also have a social focus, aiming at extending the family's social network.     

Fullerene‐Promoted Singlet‐Oxygen Photochemical Oxygenations in Glass‐Polymer Microstructured Reactors

In this paper we report the fabrication of thiolene‐based microstructured reactors (MRs) that have been specifically designed to include solid‐supported reagents within the microchannels network. We propose a convenient solution to realize reversible press‐fit, leak‐proof interconnects that greatly simplify the MR coupling to the external environment such as capillary tubing, sample reservoirs and pumps. The MRs have been used to carry out the oxidation of α‐terpinene and methionine using [60]fullerene, covalently linked to Tentagel^® and silica gel matrices, as a singlet oxygen sensitizer. High conversions have been observed for both substrates although, in the case of α‐terpinene, a partial photodegradation of the endo‐peroxide product was detected. Interestingly, in the case of methionine, a quantitative conversion to the corresponding sulfoxides was achieved in about 40 seconds, using low‐power, white LED illumination. The reaction time is considerably shorter when compared to the batch procedure that requires, for the same process, about one hour illumination and the use of a 300‐W tungsten halogen lamp.     

Effect of Cultivation Parameters on Fermentation and Hydrogen Production in the Phylum Thermotogae

The phylum Thermotogae is composed of a single class (Thermotogae), 4 orders (Thermotogales, Kosmotogales, Petrotogales, Mesoaciditogales), 5 families (Thermatogaceae, Fervidobacteriaceae, Kosmotogaceae, Petrotogaceae, Mesoaciditogaceae), and 13 genera. They have been isolated from extremely hot environments whose characteristics are reflected in the metabolic and phenotypic properties of the Thermotogae species. The metabolic versatility of Thermotogae members leads to a pool of high value-added products with application potentials in many industry fields. The low risk of contamination associated with their extreme culture conditions has made most species of the phylum attractive candidates in biotechnological processes. Almost all members of the phylum, especially those in the order Thermotogales, can produce bio-hydrogen from a variety of simple and complex sugars with yields close to the theoretical Thauer limit of 4 mol H₂/mol consumed glucose. Acetate, lactate, and L-alanine are the major organic end products. Thermotagae fermentation processes are influenced by various factors, such as hydrogen partial pressure, agitation, gas sparging, culture/headspace ratio, inoculum, pH, temperature, nitrogen sources, sulfur sources, inorganic compounds, metal ions, etc. Optimization of these parameters will help to fully unleash the biotechnological potentials of Thermotogae and promote their applications in industry. This article gives an overview of how these operational parameters could impact Thermotogae fermentation in terms of sugar consumption, hydrogen yields, and organic acids production.     

A Photoaddressable Liquid Crystalline Phase Transition in Graphene Oxide Nanocomposites

The multifunctionality of graphene has the potential to unlock important developments in nanocomposite science. However, the manipulation of graphene without interfering with its unique properties and while controlling its spatial organization remains challenging. Here, the formation of a photoaddressable liquid crystalline (LC) solution through the stabilization of graphene oxide (GO) with photocleavable brushes is described. The LC behavior leads to the thermodynamic entrapment of GO into low aspect ratio domains that fail to display the properties typically predicted for graphene nanocomposites. The morphology and structural and electronic performance of these nanocomposites are regenerated through the brush cleavage, which controls the phase transition of the LC phase. These results show that kinetic control of graphene assembly can be an attractive tool toward the dynamic regulation of processable sol states and structured percolated networks for rational composite manufacturing.     

Pressure Sensitive Adhesives Based on Epoxidized Soybean Oil: Correlation Between Curing Conditions and Rheological Properties

Renewable resources, including vegetable oils, can be used as feedstock for the manufacture of pressure sensitive adhesives (PSA) that can compete with those derived from petrochemical sources, but with the environmental benefit of being sustainable. Completely bio‐based PSA with tunable viscoelastic properties were synthesized from mixtures of epoxidized soybean oil and sebacic acid by a solvent‐free one‐step reaction, in the absence of catalyst. Curing conditions and pot‐life were determined for formulations with stoichiometric acid/epoxy ratio. Curing time ranged from the gel point (t_gel) to t_gel + 30 min at the selected temperature (170 °C) to study the correlation between the reaction, rheological behavior, and potential adhesive performance. These renewable PSA can be tailored by controlling the curing parameters according to the desired application, since the rheological profile and gel content were greatly dependent on the curing conditions. In particular, the obtained adhesives cured at 170 °C between 65 and 75 min showed the best balance between tack and cohesion.     

Toward Stretchable Self‐Powered Sensors Based on the Thermoelectric Response of PEDOT:PSS/Polyurethane Blends

The development of new flexible and stretchable sensors addresses the demands of upcoming application fields like internet‐of‐things, soft robotics, and health/structure monitoring. However, finding a reliable and robust power source to operate these devices, particularly in off‐the‐grid, maintenance‐free applications, still poses a great challenge. The exploitation of ubiquitous temperature gradients, as the source of energy, can become a practical solution, since the recent discovery of the outstanding thermoelectric properties of a conductive polymer, poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS). Unfortunately the use of PEDOT:PSS is currently constrained by its brittleness and limited processability. Herein, PEDOT:PSS is blended with a commercial elastomeric polyurethane (Lycra), to obtain tough and processable self‐standing films. A remarkable strain‐at‐break of ≈700% is achieved for blends with 90 wt% Lycra, after ethylene glycol treatment, without affecting the Seebeck voltage. For the first time the viability of these novel blends as stretchable self‐powered sensors is demonstrated.