Study On Short Period Detection Method Of Extruded Polystyrene Foam

The national standard of XPS is made on2002, and is more than10years by far. The standard stipulates that the thermal conductivity test should be done after90days of product standing time at ambient conditions. This provision is unable to guide the production, and is not conducive to the market supervision. So it’s very important to find a method for detecting the quality of the products in a short period of time.This topic studies the regularity of variation coefficient of thermal conductivity by discussing the process of XPS changes with time at different temperature, humidity and pressure. It is find that high humidity environment can slow the foaming agent outward diffusion velocity, and make the thermal performance of product maintain the stability. The pressure has no effect on XPS, because there is no gap and closely linked cell structure, and gas cannot flow, thus cannot change the properties of the product. High temperature can increase the exchanging rate of air and foaming agent, and accelerate product aging. But the higher temperature will lead to deformation, and the deformation is irreversible. So it’s very important to find a suitable temperature. It can not only speed up the product aging, but also maintain the other performance of product, and reaching the purpose of detecting at last.Based on the experiment with temperature, humidity, pressure and time, it is found t hat the XPS, which use back material as the main materials and freon as foaming agent, show the thermal conductivity coefficient close to that of90days, after standing in80℃drying oven for48h. Therefore, the XPS thermal conductivity coefficient can be me asured after standing in80℃drying oven for48h. It is no need to stand for90days, an d is time saving.