Dynamic mechanical response of VO2-UHMWPE polymer composite across the phase transition

We report the effect of phase transition of Vanadium dioxide (VO2) reinforcements in the ultra-high molecular weight polyethylene (UHMWPE) polymer matrix on the dynamic compressive strength of the composite. VO2 is well known for its insulator to metal transition above 68 degrees C along with the structural changes. VO2 -UHMWPE polymer composite is fabricated by hot-press method into a layered structure. The effect of filler's microstructure and strain rate (similar to 2600 /s to 3500 /s) are also studied through the Split Hopkinson Pressure Bar (SHPB) test. The high strain rate loading test is carried out at room temperature and 75 degrees C via modified SHPB set-up to investigate the role of the phase transition in VO2 that occurs at 68 degrees C. The developed VO2 - UHMWPE composite shows 16% and 9% enhancements in dynamic compressive strength across the phase transition for VO2 SCSFs and VO2 particles respectively. Phase transition of VO2 and composites are confirmed by DSC and the surface microstructure of the composites is confirmed by scanning electron microscope observations. Post - loading microstructural investigations are carried out with X-ray computed tomography that revealed cracks in the reinforced VO2 SCSFs. The developed composite with enhanced dynamic compressive strength provides a novel platform to design smart composites for high strain rate applications.