![]() ![]() Another way to view the surface energy is to relate it to the work required to cut a bulk sample, creating two surfaces. the polar component of surface energy increases significantly in HDPE and PP, especially when they are mechanically polished (800 grade) prior. Apart from structural changes, the modification revealed additionally a possibility to improve the wettability of the polymer. The surface energy may therefore be defined as the excess energy at the surface of a material compared to the bulk, or it is the work required to build an area of a particular surface. The surface energy of a given surface has been evaluated by measuring contact angles of sessile drops of two test liquids of known surface tension components, such as deionized water and formamide. A mechanism of polyacetylene formation, proceeding finally to cross-polymerization of the polymer was proposed. Contrary to the effect of heavy ions, He + ion bombardment was found to produce significant increase of the material hardness, which was explained by crosslinking of polyethylene. The latter in the case of Ar + ion bombardment is reflected by prevailing degradation of the surface layer of HDPE. The former diminishes for the highest ion doses, however, creation of molecular oxygen cannot be excluded. Both of them produce oxidation and lead to significant release of hydrogen. The results point on two mechanisms taking place simultaneously: ionization of polymer macromolecules and chain scission––resulting in creation of macroradicals. ![]() The consequences of the modification were studied with TOF-SIMS and FTIR-IRS techniques. This paper has been focused on structural changes of the surface layer. He + ions of energy 100 keV or Ar + ions of energy 130 keV were applied in the range of dose 1–30 × 10 15/cm 2 or 1–100 × 10 14/cm 2, respectively. Press-moulded, high density polyethylene (HDPE) samples were subjected to ion bombardment and effects of the modification studied. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |