The relationship between gas absorption and the glass transition temperature in a batch microcellular foaming process

Abstract

The glass transition temperature of polymer materials was studied in a batch microcellular foaming process. It is one of the properties which is changed when the gases such as CO 2 and N 2 are absorbed by polymers. DSC and DMA are devices that measure the glass transition temperature, but these methods are not sufficient to measure the glass transition temperature of polymers containing gases. Therefore, a new apparatus was devised by using a change of the modulus of elasticity induced near the glass transition temperature range of the polymers. The weight gain ratio of microcellular foamed polymer samples is proportional to the gas absorption. The relationship between gas absorption and the glass transition temperature in a batch microcellular foaming process was determined. It was found that the glass transition temperature of polymers drops to room temperature in this process. On the basis of the conventional Chow model and the Cha-Yoon model, estimations were made with real experimental results to predict the change of the glass transition temperature as a function of weight gain ratio of polymer materials in a batch microcellular foaming process.