The thermal behavior of a poly(methylmethacrylate) (PMMA) pigmented with titanium dioxide (TiO2) is studied in both Steady state and transient regimes in the present work. The numerical results of thermal conductivity, based on the finite element method, are compared to theoretical models and experimental measurements, which varies depending on the quenching temperature and pigment content. Time evolution of temperatures during the quenching of the composite is taken into account for different quenching temperatures and different pigment contents. It is noted that the heat exchange becomes slower for a pigment fraction of 0.5

In this study, the effects of the free quenching temperature on mechanical, thermomechanical and thermophysical properties of pigmented polystyrene (PS/TiO2) with 3% of TiO2 were investigated. Thermal conductivity and thermal diffusivity of the titanium dioxide pigmented polystyrene were measured using a periodic method. The results show a slow improvement of the notched Izod impact strength obtained after a second quenching at 15 and 35°C; whereas thermal conductivity and diffusivity reached a minimum value at the quenching temperature of 35°C. However, the effect on the thermophysical properties is only noted for the second quenching temperature 35°C. The study allowed examining the effect of quenching temperature, filler concentration and material thickness on the transient thermal behavior of the titanium dioxide pigmented polystyrene.

The effect of free quenching on the mechanical, thermal, and thermophysical properties of polystyrene has been investigated. Three different thermal treatments were investigated: a first quenching from the melt state to different temperatures, a second quenching from °C, and finally an annealing. The results have shown that a slight improvement of the impact strength can be obtained after a second quenching at 40°C, and a correlation between the mechanical and thermal properties is observed. The improvement of this property was obtained at the expense of other properties such as the elastic modulus, density, hardness, and the heat distortion temperature (HDT). The little improvement of the impact strength after the second quenching is probably linked to the existence of a relaxation mode located around 40°C. However, no effects have been shown on the thermophysical properties.

The effect of different thermal treatments on the mechanical and thermal properties of polycarbonate was investigated. The first quenching procedure which involves the quench of the samples from the melt state to different temperatures allowed improving impact strength and elongation at break for a quenching temperature of 0 degrees C. A second quenching procedure, corresponding to specimens heated again at 160 degrees C (T-g + 15 degrees C) and quenched a second time, showed a better enhancement of the impact strength and elongation at break to the detriment of other properties such as elastic modulus, density, yield stress, and heat distortion temperature, for a quenching temperature of 40 degrees C. This effect was associated to the existence of a relaxation mode around 35 degrees C. (C) 2008 Wiley Periodicals, Inc.

The effects of quenching temperature including different thermal histories on mechanical, physical, and thermal properties of pigmented polycarbonate (PC/TiO2) were investigated. Tensile test, Izod impact strength and heat distortion temperature (HDT) were performed on specimens of 3 mm thickness. Pigment content and quenching temperature are two key factors that affect the properties of the materials. A higher content of pigments results in an increase of modulus of elasticity and a decrease of unotched and notched Izod impact strength, as well as elongation at break. A maximum of yield stress and HDT is obtained at 3% of TiO2, which was considered as the optimum level of pigment. An additional second quenching at 40°C has allowed to improve Izod impact strength and elongation at break of specimens with 3% of TiO2; whereas modulus of elasticity, density, yield stress, and HDT were minimum at this quenching temperature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007