Check homogeneity, color, gels, seeds, foreign matter, phase separation, turbidity. Clear, uniform resin implies proper polymerization/dispersion.

Flow behavior for processing, grinding, leveling. Report temperature with instrument.

Polymer + non-volatiles by oven loss.

Free acid content; affects curing, adhesion, pigment wetting.

Available –OH groups; crucial for PU or amino crosslinking stoichiometry.

Free amine in epoxy hardeners/amine resins; controls cure & pot life.

Mass containing 1 equivalent of epoxide; defines hardener parts.

Pycnometer or density cup; needed for volume solids & cost/L.

Optical clarity & pigment hiding match; Abbe refractometer.

Cure speed on hot plate/gel timer; informs pot life & throughput.

DSC or R&B; correlates to hardness & heat resistance.

Acid number after neutralization with ammonia/amine → dispersion stability.

Miscibility with co-resins, plasticizers, solvents; look for haze or phase split.

% solvent addition before turbidity; informs cut-back and sprayability.

Critical for isocyanates & moisture-sensitive systems.

Low color preferred for light shades & clears.

Evaluate a cured film to simulate end-use performance.