The cure kinetics of medium reactivity unsaturated polyester resin formulated for Liquid Composite Molding process simulation was studied by Differential Scanning Calorimetry (DSC) under isothermal conditions over a specific range of temperature. For isothermal curing reactions performed at 100, 110, and 120 C, several influencing factors were evaluated using the heat evolution behavior of curing process. We propose two-and three-parameter kinetic models to describe the cure kinetics of thermoset resins. Comparisons of the model solutions with our experimental data showed that the three-parameter model was the lowest parameter model capable of capturing both the degree of cure and the curing rate qualitatively and quantitatively. The model parameters were evaluated by a non-linear multiple regression method and the temperature dependence of the kinetic rate constants thus obtained has been determined by fitting to the Arrhenius equation.

The development of new composite product for an application through liquid composite molding (LCM) process simulation requires submodels describing the raw material characteristics. The viscosity during resin cure is the major submodel required for the effective simulation of mold‐filling phase of LCM process. The viscosity of the resin system during mold filling changes as the cure reaction progresses. Applied process temperature also affects the viscosity of the resin system. Hence, a submodel describing the resin viscosity as a function of extent of cure and process temperature is required for the LCM process simulation. In this study, a correlation for viscosity during curing of medium reactive unsaturated polyester resin, which is mostly used for the LCM process, has been proposed as a function of temperature and degree of cure. The viscosity and the degree of cure of reacting resin system at different temperatures were measured by performing isothermal rheological and isothermal differential scanning calorimetry experiments, respectively. A nonlinear‐regression analysis of viscosity and degree of cure data were performed to quantify the dependence of viscosity on temperature and extent of cure reaction. Comparisons of model solutions with our experimental data showed that the proposed empirical model is capable of capturing resin viscosity as a function of extent of cure and temperature qualitatively as well as quantitatively. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

The development of a new composite product through resin transfer molding (RTM) process requires the identification of an effective injection strategy and optimization of the process variables and raw material parameters of the manufacturing process. This article presents an effective manufacturing technology for a cab front model using RTM isothermal mold-filling simulation technique. The simulations performed were based on the finite element method for which a commercial RTM simulation package was utilized. A number of isothermal mold-filling simulations using different injection strategies and process variables were carried out. Injection strategy using constant flow or pressure was executed to find optimum locations for injection ports and air vents requiring minimum mold -fill time. The effect of process variables, such as injection pressure, and raw material parameters, such as resin viscosity and mat permeability, on the mold-filling time was also studied. The simulation results show that the injection strategy of four injection points on the front face and four vents at the corners of the cab front with constant pressure of 5 atm delivers an optimum mold-fill time of 32 min without dry spots.

A Polymer Electrolyte Membrane (PEM) fuel cell is a device in which an electrochemical reaction occurs between fuel and oxidant producing electricity and water is the only by-product with zero emission. Usually, Pt nanoparticles prepared on carbon support used as oxidation and reduction reaction in PEM fuel cells. Because, carbon-supported platinum shows better oxidation and reduction activity among all the pure metals. Alloying of Pt with another non-noble metal is a strategy to develop Pt-based electrocatalysts, which reduces the Pt loading in electrodes and alters the intrinsic properties such as active sites available on surface and binding strength and electronic effect of species. Carbon support loss its catalytic activity due to electrooxidation under fuel cell operating conditions for long-term operations. In particular, the encapsulation of carbon with polyaniline (PANI) supported Pt enhances the electrode stability in fuel cells by Enhancing the Active Surface Area (EASA), chemical resistance and electron conductivity. Different supported catalysts have been proposed to improve electrochemical stability of nanoparticles in PEM fuel cells and supercapacitor.