Influence of polyethylene molecular conformation on Taylor impact measurements: a comparison of HDPE, UHMWPE, and PEX

The current work presents the comparison of the Taylor impact response of three different industrial forms of polyethylene. Specifically, high-density polyethylene (HDPE), ultra high molecular weight polyethylene (UHMWPE), and cross-linked polyethylene (PEX) were tested. From quasi-static and intermediate strain-rate compression measurements as a function of temperature (75 to 100C) and strain-rate (10$^{-4}$ to 2600 s$^{-1})$ the responses of UHMWPE and PEX are very similar, whereas HDPE exhibits some differences. The HDPE samples display a significantly higher yield stress followed by a flat flow behavior. Conversely UHMWPE and PEX both exhibit significant strain hardening after yield. Taylor impact experiments are presented as a function of velocity and temperature to probe the dynamic yield behavior and ductile-to-brittle response of these polymers.