Characterization of Two-Stage Latexes Using Dynamic Mechanical Thermal Analysis

By Brian Rearick, Shanti Swarup, Peter Kamarchik

Coatings prepared from two-stage acrylic latexes were characterized using dynamic mechanical thermal analysis (DMTA). The DMTA data, in conjunction with additional supporting data (differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and particle size analysis), provided detailed information on copolymer compositions, latex particle morphologies, and coating morphologies.

Depending on monomer selection and monomer order of addition during polymerization, one of three different particle morphologies was obtained: two particles of different composition, two-phase particles, or interpenetrating polymer network (IPN) particles. Coating performance was highly dependent on latex and coating morphologies, as well as monomer composition. IPN latex morphologies produced coatings with superior mechanical properties and chemical resistance.