Deformation Phenomena of Thermoplastic Materials in the Solid and Semifluid States

Abstract

The deformation phenomena of a thermoplastic elastomer, a polyamide 12 and a polyketone, are analyzed to identify the polymer characteristics that enhance the processability of a material both at temperatures around the melting point (i.e., in a semifluid state) and at temperatures close to ambient conditions. Dissipation factor isotherms in the frequency range associated with hot compaction, used in conjunction with a hot‐pressing technique that identifies the minimum temperature required for significant chain mobility during hot compaction, allow to evaluate the processability in the semifluid state. The experiments show that optimal processing by hot compaction is achieved when tan δ > 2 for the entire frequency range under consideration. Showing superior processability with respect to the other two polymers, the polyamide 12 is then compounded with a polyamide 12‐based elastomer to tune its stiffness and toughness in tension and bending, enhancing its cold forming characteristics. POLYM. ENG. SCI., 60:535–540, 2020. © 2019 Society of Plastics Engineers