Effect of N_2 Ion Bombardment on Optical and Mechanical Properties of Ultra-high Molecular Weight Polyethylene (UHMWPE)

摘要

The effect of ion beam bombardment on the optical and mechanical properties of ultrahigh molecular weight polyethylene (UHMWPE) was investigated. UHMWPE polymer samples were bombarded with 150 keV N_2 ions under vacuum at room temperature to high fluences ranging from 1x10~(16) to 2x10~(17) ions cm~(-2). The untreated as well as treated samples were investigated by ultraviolet-visible (UV-Vis) spectrophotometer and Vicker's micro-hardness techniques. The direct and indirect optical band gap decreased from 2.9 and 1.65 eV for pristine sample to 1.7 and 1 eV for those bombarded with N_2 ion beam at the highest fluence, respectively. With increasing ion fluence, an increase in the number of carbon atoms per conjugation length, N and number of carbon atoms per cluster, M in a formed cluster were observed. A significant improvement in surface hardness was obtained by increasing the ion fluence.