The effect of antioxidants on the surface oxidation and surface cracking of crosslinked polydimethylsiloxane

Crosslinked polydimethylsiloxanes with three different chain-breaking antio xidants (Irganox 1076, Irganox 565 and Tinuvin 770) were exposed to air pla sma (GHz), and the surface structures of the exposed samples were assessed by contact angle measurements, X-ray photoelectron spectroscopy, optical an d scanning electron microscopy, and surface profilometry before and after u niaxial stretching. It was found that samples containing antioxidants oxidi zed more slowly than the reference sample with no antioxidant. Higher doses of air plasma were required to form a brittle silica-like layer in the sam ples with antioxidant than in the reference sample with no antioxidant. Tin uvin 770 showed the strongest antioxidative effect whereas Irganox 1076 and Irganox 565 were similar in efficiency. (C) 2001 Elsevier Science Ltd. All rights reserved.