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Rheology assessment is an important tool to understand membrane process formation as well as membrane morphology and properties. Hence, by varying the GRAFIM® content and adding silver nanoparticles, polysulfone composite membranes were prepared through the wet-phase inversion method with N-methyl-2-pyrrolidone as a solvent and water as a nonsolvent. Newtonian fluids were obtained, and silver nanoparticle dispersions presented the highest viscosities. Water diffusion was Fickian in both systems, and their coefficients decreased by increasing their viscosity. Dense surfaces characterized GRAFIM® membranes, whereas nanoporous surfaces were present in silver nanoparticle membranes due to their higher dispersion viscosity. Both thermodynamical favoring and rheological hindrance led to membrane formation. GRAFIM® and silver nanoparticles positively influenced water sorption, linear expansion, porosity, and hydrophilicity. Finally, these membranes presented high values of water permeability due to their high porosity, cutoff in the range of nanofiltration, which were lower for the membranes with only GRAFIM® and favorable values of saline rejection for four used salts (NaCl, Na2SO4, MgCl2, and MgSO4). [ABSTRACT FROM AUTHOR]

Abstract: Instrumented indentation has been used to investigate the mechanical properties of BETAMATE 1496® Epoxy adhesive. The properties of the adhesive were analyzed by measuring its hardness and its Young''s modulus in samples extracted from six different positions of the front door of a commercial passenger vehicle in two phases of processing: after application of the adhesive in the door assembling (“pre-cured” state) and after final cure in the painting oven (“cured” state). Special attention was given to setting the optimal parameters (“creep” time and unloading time step) for the instrumented indentation testing for the present application. Young''s modulus values around 1.1±0.2GPa and hardness values around 0.15±0.05GPa were obtained for all samples, irrespective of the variation of the indentation parameters in the testing procedure and of the relative position of the adhesive in the door frame in both states. [Copyright &y& Elsevier]

Abstract: This paper shows the results of preliminary assessment to devulcanize and recover the bromobutyl rubber (BIIR) using the microwave process. In this work, a heat generating system with high microwave frequency (2.45GHz) was used. Samples of BIIR (about 0.250kg) such as rubber caps production leftovers and materials that had not been approved in the quality tests were irradiated, at powers of 1000W, 2000W and 3000W. Various heating times were used: 540s (9min) up to 1500s (25min). The standard test specimens of non-irradiated and irradiated samples were characterized by rheometric analysis, Shore A hardness measurement and ash test. The best operation conditions were obtained at 780s and 2000W. The results showed that the microwave process caused an expressive effect in the BIIR recovery. Some samples presented the tendency to vulcanize again, hence there is a great expectancy for reusing and recycling the devulcanized BIIR, without using any chemical agent in the microwave process. [Copyright &y& Elsevier]