NETWORK FORMATION OF VINYLESTER-STYRENE COMPOSITE MATRIX RESINS

Vinylester-styrene network formation was monitored by FTIR under condi tions typically used for ''on-line'' composite processing. Reactions o f the carbon-carbon double bonds of the methacrylate (943 cm(-1)) and styrene (910 cm(-1)) were followed independently. A background spectru m derived from the fully cured resin was subtracted from the spectra c ollected as a function of reaction time to quantify conversion data ob tained at 140 degrees C on a series of resins with systematically incr easing levels of styrene as r(s)=0.36 and r(m)=0.24. The data was anal yzed using the integrated form of the copolymerization equation and as suming a terminal reactivity model to predict copolymer compositions t hroughout the reactions. These curves agreed well with experimental da ta even at high conversions.