Iranian Journal of Chemical Engineering (IJChE)

Abstract The synthesized polystyrene has weaknesses in terms of mechanical, physical and thermal properties which limit the use of this polymer. Therefore, the use of the mixtures of polymers can improve these properties. Different parameters like the mixing speed can affect the quality of the properties of the polymer being prepared from the mixture of several polymers. In this study, different percentages of nanocomposites in different stirring speeds have been added to polystyrene. Different tests have been performed on the prepared polymer and investigating the tests shows that in different stirring speeds the values of the tensile strength and impact resistance of the prepared polymer can be increased while the values of the Vicat Softening Temperature (vicat) and Melt Flow Index (MFI) test numbers remain constant. The obtained results from the laboratory data have been simulated by Artificial Neural Networks (ANNs) in order to predict the results for the points which have not been tested and the simulated results show that the laboratory data covered the simulated data perfectly. The results of tests show that by increasing nanoparticles, the resistance of the polymer against impacts will be increased and in addition, increasing the rate of the stirrer causes all other values of tests to increase.

Abstract Migration of styrene monomer from polystyrene (PS) dishes was conducted during this research at temperatures of 5, 20, and 40 °C. According to the Food and Drug Administration (FDA) regulations, these experiments were performed in contact with 10%ethanol as a food simulant for the oil in water (o/w) emulsions. The dishes were filled in each of the defined temperatures and stored for 35 days. In relatively close intervals (1, 7, 15, 24, and 35 days) the amount of migration which occurred was determined by means of Head Space Gas Chromatography Mass Spectrometry (HS-GC-MS). By increasing storage time and temperature, the amount of migration was increased and in all times and temperatures styrene monomer was detected. In addition, a mathematical model based on the Fick’s second law was validated to predict migration from packaging material into the 10% ethanol. The resulted diffusion coefficients were 3.6×10-18, 4.9×10 -18, and 6×10 -18 (m2/s) in 5 ,20 and 40 °C respectively.

Abstract In the present work, a population balance model is used to predict dynamic evolution of droplet/particle size distribution in non-reactive liquid-liquid dispersions and reactive liquid (solid)-liquid suspension polymerization systems. The effect of dispersed phase hold-up and agitation rate on droplet/particle size and droplet/particle size distribution are investigated. The cell average technique is applied for solving the population balance equation. Predictive capability of the presented model is demonstrated by comparison of model predictions with experimental data regarding the average mean diameter for non-reactive liquid-liquid dispersions and the free-radical suspension polymerization of styrene.