Cure behavior of DGEBA vinyl ester-styrene resins near silane-treated interfaces

An experimental technique using FTIR-ATR was developed for monitoring the copolymerization behavior of a DGEBA-based vinyl ester (VE) and styrene (ST) near the surface of a germanium internal reflection element. The data were compared to previously obtained bulk measurements of the cure behavior. It was found that the extent of conversion may be slightly greater for ST and slightly lower for VE near an untreated interface compared to the bulk. The cure behavior of VE-ST in the vicinity of a germanium IRE surface treated with a styryl amine silane (Dow Corning Z-6032) was also investigated. In this case the effect on the cure was more dramatic, as exhibited by a more rapid consumption of ST compared to VE, thus resulting in a greatly reduced final conversion of VE double bonds compared to the bulk. These results suggest that, in glass fiber-reinforced composites, such sizings could significantly alter the composition of the crosslinked network in the vicinity of a fiber surface with the potential for a lower T-g interphase being formed that is rich in homopolymerized styrene. (c) 2006 Wiley Periodicals, Inc.