Fluorinated Hydroxytelechelic Polybutadiene as Additive in Cationic Photopolymerization of an Epoxy Resin

Fluorinated hydroxytelechelic polybutadiene (PBF), which is synthesized from the radical addition of a fluorinated mercaptan onto a hydroxytelechelic polybutadiene was used as an efficient surface and mechanical modifier in original formulations to enable the UV cationic polymerization of a telechelic diepoxy cycloaliphatic oligomer, leading to crosslinked polymers. Various amounts of PBF were used (ranging between 0 and 15 wt %). The kinetics of photocrosslinking revealed that the diepoxyde conversion reached 70% only in the absence of PBF, whereas it was about 90% in the presence of 10 wt % of PBF. When the PBF content increased, the dynamic mechanical measurements showed that: (i) the glass transition temperature values decreased and (ii) the resilience increased. The hydrophobicity of these polymers was investigated from the water contact angle (WCA) values showing a surface modification of the epoxy-based system. Indeed, great modifications were noted on the extreme surface (i.e., air side) of the polymers (with WCA values as high as 120 degrees) in contrast to those observed on the substrate side. (c) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2835-2842, 2009