Lenka Zajíčková, Marek Eliáš, Vilma Buršíková, Zuzana Studýnková, Věra Mazánková, Miroslav Michlíček, Jana Houdková
Low Pressure Plasmachemical Processing of Multi-Walled Carbon Nanotubes for the Production of Polyurethane Composite Films with Improved Mechanical Properties
Thin Solid Films 538 (2013) 7-15
Multiwalled carbon nanotubes (CNTs) were modified in low pressure capacitively cou- pled discharges (13.56 and 27.12 MHz) in Ar/NH3 and oxygen-containing gas mix- tures. A direct functionalization by nitrogen groups was not possible but 1–3 % of nitrogen, as determined by X-ray photoelectron spectroscopy, was attached after the exposure of plasma activated CNTs to air. The maximum oxygen content of 17–21 % was achieved in Ar/O2 , Ar/CO2 and O2 /C2 H6 O. The percentage of carbon-oxygen bonds increased with the total oxygen content on the expenses of sp2 C almost inde- pendently on the plasma conditions. The plasma modified CNTs were used as fillers for polyurethane (PU) composites prepared by in situ polymerization. The composites were investigated by depth sensing indentation that revealed the existence of surface harder layer caused probably by different polymerization process in the bulk and at the surface that was in a contact with air. The significant improvement of the hardness and elastic modulus was observed when plasma-modified CNTs with high amount of oxygen were added to PU. It also improved the creep resistance of the PU whereas the ability to recover from a deformation, i. e. anelastic recovery, did not change much.
DOI: 10.1016/j.tsf.2012.11.126
You can also contact one of the authors: lenkaz@physics.muni.cz, mareke@physics.muni.cz, vilmab@physics.muni.cz, michlicekm@gmail.com