Crosslink Density of Epoxy Cured Acrylic Resins at Different Temperatures

Crosslink density (XLD) is one of the important structural parameters characterizing a crosslinked polymer. Physical and mechanical properties of crosslinked polymer are significantly influenced by variation in the magnitude of XLD. In the present work, a carboxyl functional acrylic resin was crosslinked with different epoxy resins. Their films were immersed in methyl ethyl ketone and the increase in dimensions of the swollen films under equilibrium swelling conditions was used to calculate crosslink density by using the Flory–Rehner equation. Results demonstrated that the crosslink density increased by increasing in crosslinker content and cure temperature but it decreased by increasing the molecular weight of crosslinker. It was also found that the curing reactions were going to completion at 170oC and 40 min when the carboxyl/epoxy ratio was 1:1. The mentioned conditions are important from a commercial point of view.

Keywords:

acrylic resins , epoxy resins , crosslink density , equilibrium swelling