Nanotechnology Approach to Lightweight, Multifunctional Polyethylene Composite Materials

Of several ideas being pursued by NASA for the reduction of radiation dosage to astronauts, the use of ultra-high-molecular-weight polyethylene (UHMWPE)-based composite materials for both radiation shielding and micrometeorite shielding appears to be particularly appealing. UHMWPE has long been understood to provide superior radiation shielding following encounters with energetic nucleons due to its high hydrogen content. Meanwhile, impacts of micrometeorites with UHMWPE tend to vaporize it, rather than causing spallation of the shield material, which then creates additional potentially damaging micrometeorites. Less widely appreciated is the high specific strength of UHMWPE and UHMWPE fibers, which provide structural integrity to the composite. Amongst thermoplastics, UHMWPE has the highest impact strength and is also highly resistant to abrasion. Despite this highly appealing combination of properties, UHMWPE’s key mechanical properties can be improved by forming composites with other nanostructured materials, leading to further performance increases and weight reductions. Such composites will increase the ability of UHMWPE structures to withstand micrometeorite impacts and maintain the structural integrity of a pressurized environment.