The Challenge

Thermoplastic elastomers have good elasticity and fatigue properties and are gaining popularity in biomedical applications. For these materials to be considered for use in prosthetic heart valves it is important to understand their behaviour under cyclic loading and unloading. Evidence of hysteresis during the process and the minimum number of pre-conditioning cycles before the material can be considered in steady state is also important. This evidence must be obtained from non-destructive structural measurements of the dynamic system operating in real time over many thousands of repeat cycles of loading and unloading.

The Solution

The non crystalline diffraction beamline, I22, at Diamond is ideally suited for study of soft condensed matter systems such as polymers and composites. The high intensity X-ray source coupled with the ability to make structural measurements on the millisecond timescale allows real time dynamic measurements. These dynamic measurements were used to evaluate the response of the material to mechanical stress and the reversibility of the response over an extended number of cycles.

The Benefits

The measurements allowed the research team to monitor microstructural evolution in real time, mimicking the beating of a prosthetic heart. The results obtained show that these novel materials may be suitable candidates for use in prosthetic heart valves.