The effect of the reaction medium on the final electrical performance of Pani doped with dodecylbenzene sulfonic acid (DBSA), Pani.DBSA, is analyzed in this manuscript. Pani.DBSA was synthesized through the one-step route in nonaromatic media, in accordance with a mixture experimental design. Polymer samples were analyzed by UV-vis and WAXS to characterize the differences among the many prepared Pani.DBSA samples and to explain the observed conductivity and compression sensitivity characteristics. Obtained results were modeled in accordance with a standard empirical modeling approach. Based on the obtained experimental data and on the proposed empirical models, it is shown that addition of acetone and isopropanol into the aqueous media during the one-step synthesis of Pani.DBSA materials must be encouraged.

Electrically conducting composites based on polyaniline‐H2SO4/polycardanol were prepared with a mechanical mixing method. The influence of the composition on the electrical performance of the composites was evaluated. Materials were characterized by Fourier Transform Infrared Analysis and Near Infrared Analysis. X‐Ray Photoelectron Spectroscopy analyses were used to explain the different electrical behavior of these composites. The bioconductive materials showed low percolation thresholds and low electrical resistances, allowing for use as pressure sensing materials. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers

Abstract:Data reconciliation is a model-based technique that reduces measurement errors by making use of redundancies in process data. It is largely applied in modern process industries, being commercially available in software tools. Based on industrial applications reported in the literature, we have identified and tested different configuration settings providing a numerical assessment on the performance of several important aspects involved in the solution of nonlinear steady-state data reconciliation that are generally overlooked. The discussed items are comprised of problem formulation, regarding the presence of estimated parameters in the objective function; solution approach when applying nonlinear programming solvers; methods for estimating objective function gradients; initial guess; and optimization algorithm. The study is based on simulations of a rigorous and validated model of a real offshore oil production system. The assessment includes evaluations of solution robustness, constraint violation at convergence, and computational cost. In addition, we propose the use of a global test to detect inconsistencies in the formulation and in the solution of the problem. Results show that different settings have a great impact on the performance of reconciliation procedures, often leading to local solutions. The question of how to satisfactorily solve the data reconciliation problem is discussed so as to obtain improved estimates.

Sheets of cellulosic paper were modified with PAni nanoparticles through a chromatographic process. When exposed to acidic conditions, strips of the modified paper sheets are subject to RGB color changes that can be detected by a scanner (and similar devices used for image analyses). As a consequence, cellulosic paper sheets modified with PAni can be used for analyses of acid concentrations in liquid and gaseous streams. Aqueous solutions of hydrochloric acid were used for modeling purposes and it was observed that color changes were most significant when the HCl content was between 0–500 ppm range. Materials were characterized by FT‐IR spectroscopy, optical microscopy, AFM, and SAXS techniques, in order to reveal the main characteristics of the produced materials.magnified image

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This article describes a method for the determination of kinetic constants in aniline polymerizations performed in the presence of dodecylbenzene sulfonic acid. The procedure was based on the measurement of light absorbances at 668 and 1026 nm. The absorption at 668 nm is related to pernigraniline formation and is ordinarily used for ultraviolet-visible kinetic studies. The absorption at 1026 nm is related to the second overtone of the NAH bonds, which may be used to monitor the aniline consumption along the reaction time. Tzou and Gregory's empirical reaction model was used as a reference for kinetic studies. The best fits were obtained when the kinetic constants were evaluated at 1026 nm because of the lower noise/signal ratio in this spectral region and the smaller sensitivity to the pernigraniline/emeraldine transition during the last stages of the polymerization. The remarkable innovation supplied by this study is the possibility to study aniline polymerizations in situ in realistic reaction conditions, which will allow the use of concentrated monomer solutions, large reaction volumes, efficient cooling conditions, and agitation.

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