Advanced Extraction Resistant Long-Term Thermal Stabilizers for Polyolefin Pipes

Abstract

For many years, sterically hindered phenols have been the standard for the long-term thermal stabilization of polyolefin pipes. Recently, an advanced stabilization system was developed which offers better gas and water extraction resistance than these phenolic systems, thus being able to better fulfill the stringent requirement of guaranteeing a pipe lifetime of more than 50 years. In this paper, current standard phenolic antioxidant pipe formulations are compared to new hindered amine thermal stabilizer (HATS) formulations in different polyolefins. The data show that the new HATS systems are better able to maintain the mechanical properties, molar mass, and thermo-oxidative stability of the pipe resins during exposure time.