Effect of temperature on the volume and rate of gas emissions from polystyrene pattern evaporated in the full mould process

The technologies which use foamed expandable polystyrene patterns (or patte rns made of similar materials) are characterised by numerous advantages, ma inly technological, but also economic and ecological. Simple equipment redu ces the energy consumption and emission rate of impurities. The properly de signed solid pattern eliminates parting planes and flashes on castings, red ucing in this way to a considerable extent the finishing treatment of casti ng done by hand and minimalising the necessary machining. The use of negative pressure in mould on pouring and cooling of castings cr eates favourable conditions for collecting the gaseous products of a therma l destruction of patterns. The gases can be next neutralised or absorbed by specially chosen absorbers which makes the process clean and friently to t he environment. In this study the kinetics of the gas emission from patterns of various den sities, evaporated at different temperatures, has been described along with its effect on the time of evaporation of these patterns.