The preparation and thermomechanical properties of high‐temperature foams based on thermoplastic poly(phthalazinone ether ketone)

Abstract

AbstractPoly(phthalazinone ether ketone) (PPEK) is an amorphous thermoplastic polymer with a high glass transition temperature (Tg) exceeding 250°C. We describe the preparation of foams from PPEK and characterize their properties. PPEK foams were prepared using dichloromethane as a foaming agent. The foaming agent was swollen into discs of the PPEK, which were then foamed by heating. Foams could be prepared at temperatures far below the Tg of the PPEK due to plasticization of the polymer by the foaming agent. Foams with densities ranging from 0.1 to 0.65 g/cm3 were prepared. Their thermal conductivity and modulus (measured approximately by indentation tests) were found to decrease with density, and the trends were similar to those expected from existing models. The foams could be annealed at 200°C without collapse suggesting that they may be useful in structural or insulation applications where stability at high temperature is essential.