Search

The specific influence of polyethersulfone (PES) end-functionalization with chlorine or hydroxyl end groups at same molar mass on PES-epoxy composites based on a high-performance tetra-epoxide with di-amine hardener resin (RTM6) is investigated in terms of morphology, thermal behavior, and toughness. A model study on PES filaments embedded in epoxy precursor is first performed to compare the interdiffusion and resulting morphology upon curing. PES-OH shows a larger interdiffusion distance compared to PES-CI in the model systems and the laminates. This effect is more pronounced at high heating rate. Cross sections and fracture surfaces of composite panels are analyzed by scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) spectroscopy to establish the link between the microstructures and fracture mechanisms. The toughness of PES-OH-modified epoxy composites is doubled compared to unmodified reference panels, whereas the PES-CI shows no improvement. The favorable influence of PES-OH is ascribed to enhanced miscibility, interfacial adhesion and morphology, resulting from the better affinity between hydroxyl-terminated PES and the epoxy-resin., INTRODUCTION Composite materials based on carbon fibers (CFs) and high-performance epoxy resins are increasingly used in high-end structural applications because of their excellent specific stiffness and strength as well as [...]

The interdiffusion between a low and a high viscosity epoxy resin was studied on model systems representing the novel composite manufacturing process called 'Same Qualified-Resin Transfer Molding' (SQ-RTM). Neat resin model systems were first characterized after curing by Raman spectroscopy, energy dispersive X-ray microscopy, and nano-indentation, all methods reveal an interdiffusion distance of about 700-900 urn. Transmission electron microscopy further revealed a complex morphological gradient structure in the interdiffusion zone. The interdiffusion distance was about 800 µm in the absence of carbon fibers, reducing down to 500 µm when the viscous resin was replaced by the corresponding prepreg, due to the geometrical constraints imposed by the fibers. Moreover, some asymmetry was observed in the interdiffusion profile because of the viscosity difference between the resins. The results obtained on the model systems were found to match very well the interdiffusion profiles generated in real SQ-RTM composites processed with the same combination of resins., INTRODUCTION The use of composite materials based on carbon fabric-reinforced thermoset resins in structural aircraft applications keeps expanding because of the unique combination of mechanical properties, low density, and high [...]

Reducing input use and in particular pesticide use is very important in OIV 2018 new resolutions. Also Europe and France promote research and co-design with winegrowers in more sustainable viticulture according to a combination of climate change. It is also very important to take into account soil diversity and Protected Designation Areas constraints to make sure that new wines will ensure the sustainability of the wineries. This study explores design, experiment and assess of new realistic viticulture production systems located in Protected Designation of Origin (PDO) areas and with already organic or biodynamic certification for six consecutive years, in winery production conditions. It also discusses the chosen assessment indicators and the adoption of such new production systems by winegrowers. Eleven cases were studied in a system experiment network in Alsace (France) and in six consecutive production years. Contrasted production years, PDO areas combined to organic or biodynamic certification allow testing the resilience of experimented systems over time. Combination of new practices are tested to drastically reduce input and in particular pesticide. Assessed performances of the systems deal with 14 main indicators: social acceptability (1) and economic viability (1), agronomy (yield (1), harvested berries quality (2), fungi damage (3), soil quality (1), and wine sensorial analysis (1) and environment (Frequency Treatment Index (1), Cupper rate (1), INDIGO® method (2)). Several innovations were selected by co-design with winegrowers: adding essential oil and Propolis to copper spraying; total grass cover of the vine site; new decision rules for rate and time pesticide spraying; decision aid tool; resistant grape varieties planted. The assessment results support that the performance of the 14 indicators is very good for most of the eleven systems during the six assessed years. Combinations of tested innovations are neither dangerous nor difficult to enforce in the field by the vineworkers. Innovations do not increase the cost of grape production. The yield ratios were satisfactory the 6-yeared of observation because calculated yield match with targeted yield. Harvested berries quality support that the 7 vine sites succeed in targeted total acidity and sugar rate according to the different PDO conditions every years. Wines were Alsace or Grand Cru PDO labelled and successful marketed. At least, the Treatment Frequency Index is reduced by an average of 40% for all vine sites and assessed years. TFI can be reduced at a maximum of 89% and TFI median is 38%. Cupper rate can be reduced at a maximum of 97% and Cupper rate median is 54%. I-pest from INDIGO® method indicate a minimal risk taking for groundwater, surface water, air and beneficial organisms contamination. And finally, flora richness indicator is stable or steadily increases during the 6 study years. In this study, we demonstrated that drastically monitoring reduction of pesticide and other inputs is possible. Chosen indicators allow a exhaustive assessment, but could also been aggregated all together to give a synthetic information to winegrowers and make them easier to adopt the innovative systems. Introduction of innovation combinations in highly sustainable organic and biodymanic systems are validated to produce high quality wines. Now, it is possible to serenely promote and disseminate these highly sustainable innovative systems, taking into account of course vineyard diversity.