Relationship between the network morphology and properties of commercial vinyl ester resins

Two commercial vinyl ester resins, Derakane 411-350 (resin D) and Derakane 411-350 Momentum (resin M), were characterized. Despite the large quantity of publications in the literature about vinyl ester resins few experimental results have been reported for resin M. The effect of the Styrene content on the mechanical properties and morphological structure was studied. An increase in the styrene content produced a network with a low storage modulus in the rubber state and a glass-transition temperature. The apparent average molecular weight between crosslink points and glass-transition temperature were slightly higher for resin D than for resin M. The Fourier transform infrared spectra and molecular weight distributions were similar. However, resin M was tougher than resin D, and this may have been due to the closer structure in the fully Cured state. Atomic force microscopy was performed for each cured resin and confirmed the difference in the nanostructures. The main reason for the differences in the developed structures was the use of an accelerator, which influenced the final morphology. (c) 2006 Wiley Periodicals, Inc.