On compression and damage evolution in two thermoplastics

Abstract

The well-known Taylor cylinder impact test, which follows the impact of a flat-ended cylindrical rod onto a rigid stationary anvil, is conducted over a range of impact speeds for two polymers, polytetrafluoroethylene (PTFE) and polyetheretherketone (PEEK). In previous work, experiments and a model were developed to capture the deformation behaviour of the cylinder after impact. These works showed a region in which spatial and temporal variation of both longitudinal and radial deformation provided evidence of changes in phase within the material. In this further series of experiments, this region is imaged in a range of impacted targets at the Diamond synchrotron. Further techniques were fielded to resolve compressed regions within the recovered polymer cylinders that showed a fracture zone in the impact region. The combination of macroscopic high-speed photography and three-dimensional X-ray imaging has identified the development of failure with these polymers and shown that there is no abrupt transition in behaviours but rather a continuous range of responses to competing operating mechanisms. The behaviours noted in PEEK in these polymers show critical gaps in understanding of polymer high strain-rate response.

PEEK surface modification by fast ambient-temperature sulfonation for bone implant applications

“…PEEK is a semi-crystalline, polycyclic thermoplastic. In its unmodified state, its Young's modulus is around 3.6 GPa; when reinforced with carbon fibres, its Young's modulus improves to around 18 GPa, close to that of human cortical bone [9,10]. Moreover, PEEK is biocompatible, chemically and physically stable, and features many further advantages when compared with traditional metal and ceramic implants.…”

Thermo-Mechanical Behavior of Poly(ether ether ketone): Experiments and Modeling

“…Experimental data in cyclic and fatigue tests are presented in [ 10 , 14 , 25 , 26 , 27 , 28 , 29 ]. Observations in the Izod impact tests are given in [ 13 , 14 , 30 ], whereas those in the Taylor impact tests are provided in [ 31 , 32 , 33 ]. Observations in nanoindentation tests are discussed in [ 34 , 35 ].…”