(Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 109: 857-864)”
“This work presents a theoretical and experimental study on the Inhibitor Library specific migration process, describing the mass transfer of a model migrant Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (I-1076), an antioxidant commonly used in the polyolefins processing. Film samples (LDPE), with
initial concentration of Irganox between 1000 and 6000 (mg/kg), and thickness of 50-190 mu m, were placed in contact with fatty (EtOH 95%) and aqueous (EtOH 10%) food simulants at 40 degrees C for 20 days, in order to obtain the concentration evolution in the food simulant which was measured by HPLC. On the other hand, a phenomenological model based on a resistances-in-series approach was developed considering
the diffusion through the polymer film, natural convection in the food simulant and the thermodynamic equilibrium between the polymer and the liquid simulant phase. For the thickest films, the diffusion coefficient of I-1076 see more through the polymer phase was estimated varying between 1.95.10(-13) (m(2) s(-1)) and 2.0-10(-13) (m(2) s(-1)) at 40 degrees C. On the contrary, the thinnest one shows a significant decrease of the diffusion coefficient value, which was evaluated in 1.0.10(-14) (m(2) s(-1)). This modification can be explained by means of a crystal distribution and size in the thinnest polymer film prepared by CAST extrusion. The mathematical model developed is a tool for prediction and analysis which can be used to facilitate the characterization of polymers, and it could predict the response as packaging for food in a specific application. (C) 2010 Elsevier Ltd. All rights reserved.”
“Blends of bisphenol A polycarbonate (PC) and polyamide 6,6 (PA6,6) were prepared directly during the plasticization step of an injection molding process in an attempt to attain both (i) the reinforcement of the blends through fibrillar morphology, and (ii) an adequate compatibilization despite the
short processing procedure used. Differential scanning calorimetry and dynamic-mechanical analysis indicated that the blends were made up of a PC-rich phase Selleck Citarinostat where some PA6,6 was present and, ruling out a possible degradation, of an almost pure PA6,6-phase. The cryogenically fractured surfaces observed by scanning electron microscopy showed both rather fine particles and larger particles with occluded subparticles. This complex morphology indicates low interphase tension and, therefore, compatibilization, which can be attributed to the presence of PA6,6 in the two phases of the blends. The values of Young’s modulus, determined by means of tensile tests, were always synergistic and, in the case of the 25/75 blend, the modulus was even higher than those of any of the two pure components. It appears this could be due to both the highly fibrillar morphology of the dispersed phase, and the significant decrease observed in specific volume.