Thermal analysis for dynamic behavior of microcellular polycarbonate

The dynamic behavior of microcellular polycarbonate for different densities at different temperatures and frequencies was investigated by means of dynamic mechanical thermal analysis. The relations of storage modulus and loss factor with temperature, frequency and density were discussed at the same time.Furthermore, the relation of glass transition temperature of microcellular polycarbonate with density was also discussed. The results show that when the microcellular polycarbonate is at high frequency or low temperature, the storage modulus is decreased and the loss factor is increased with increasing temperature. Meanwhile, when the temperature is higher than the glass transition temperature of microcellular polycarbonate or the frequency is very low, the storage modulus and the loss factor are decreased significantly with increasing temperature or decreasing frequency . In addition, the experimental results also show that the glass transition temperature of microcellular polycarbonate is about 175℃ and the secondary transition temperature of microcellular polycarbonate is in the range of 70~100℃, which almost have nothing to do with density.