Correlating Moisture Diffusion and Cure behavior of Vinyl Ester Resin / Organoclay Nanocomposites

Vinyl ester resin (VER) is amongst the most widely used thermoset polymers in marine and commercial industries due to its attractive features such as exceptional chemical resistance, thermal stability and mechanical strength. Recently, the application of nanoparticles such as organoclay has led to developing VER based nanocomposites with superior moisture diffusion properties. However, despite the fact that the chemical reactions involve the cure process could largely affect final properties of the cured systems, the investigations concerning the correlation between cure behavior and moisture diffusion of such nanocomposites are rare in open literature. To shed light in this issue, in the present work, rheometry and water diffusivity experiments were conducted on VER/organoclay nanocomposites with various organoclay contents (0-5 % wt%). The most interesting point regarding the effect of organoclay on the cure behavior of VER systems was the chemisorption and physisorption of the reacting monomers and initiator molecules on the organoclay platelets surface which is appeared to be responsible for the higher state of cure. Accordingly, comparing the rheological and diffusivity studies indicated that the higher is the cure state, the lower is the equilibrium moisture content. Such phenomenon suggested that the incorporation of the nanoclay could build a perfect network which reduced the water uptake.

Keywords:

Vinyl ester resin , Nanocomposites , Cure behavior , Moisture diffusion