Network formation of vinylester-styrene composite matrix resins

Vinylester-styrene network formation was monitored by FTIR under conditions typically used for "on-line" composite processing. Reactions of the carbon-carbon double bonds of the methacrylate (943 cm(-1)) and styrene (910 cm(-1)) were followed independently. A background spectrum derived from the fully cured resin was subtracted from the spectra collected as a function of reaction time to quantify conversion data obtained at 140 degrees C on a series of resins with systematically increasing levels of styrene as r(s)=0.36 and r(m)=0.24. The data was analyzed using the integrated form of the copolymerization equation and assuming a terminal reactivity model to predict copolymer compositions throughout the reactions. These curves agreed well with experimental data even at high conversions.