FOAMING POLYETHYLENE WITH CO_2-BASED MIXTURES OF BLOWING AGENTS

摘要

Carbon dioxide (CO_2) is presenting many highly desirable properties as physical foaming agent. It is a low cost and non-flammable gas with good blowing power and fast dissolution in polymers. Unfortunately, extrusion of low density foams blown from CO_2 is still very difficult. This is especially true for foams made from semi-crystalline polymers such as polyethylene (PE). This paper describes the properties and performance of polyethylene foams made from mixtures of CO_2 and 1,1,1,2-tetrafluoroethane (HFC-134a). The use of HFC-134a as co-blowing agent was shown to enable the extrusion of lower density foams as compared to samples processed with CO_2 alone.