Foamability of Thermoplastic Vulcanizates (TPVs) Using Waste Ground Rubber Tire Powder

摘要

Thermoplastic vulcanizates (TPVs) is a special class of thermoplastic elastomers (TPEs) made of a rubber/plastic polymer mixture in which the rubber phase is highly vulcanized. It is prepared by melt mixing a thermoplastic with an elastomer and by in-situ crosslinking of the rubber phase. The use of ground tire rubber (GRT) as a disperse elastomeric phase in a PP matrix offers an interesting opportunity for materials recycling of waste rubber. The properties of GRT/PP blends show similar to TPVs and are therefore regarded as a thermoplastic vulcanizate. The development of TPV foaming technology is to fulfill the requirement of achieving lower cost, lighter weight and better fuel economy, the foaming of TPVs presents an important milestone in many applications such as trunk and door seals. The main foaming methods for TPVs include the chemically blown, water foaming and microcellular foaming. Foaming of TPV using GRT has not well been investigated. In order to develop new applications for GRT, we study the foaming behavior of TPVs using GRT with various blowing agents. The effect of blowing agent type and concentration on the expansion behaviour, the cell-number density and the foam structure under the different processing conditions are examined. These experimental results will be used to determine optimized TPVs using GRT formulations to ensure good foamability.