UV Curing Characterization By Rheological Techniques

摘要

The curing profiles of thermoset materials such as epoxies are routinely characterized by rheological techniques. Rheological techniques measure mechanical properties such as viscosity and elasticity which can define a material's processing behavior related to gel point, gel time, degree of cure, cure times, reaction rate, activation energy, etc. By combining a commercially available rheometer with a precision light delivery device, this same technique can now be applied to UV Curable materials. Determination of rheological properties and curing kinetics in several UV curing systems are explored using a specially equipped rheometer. Evaluations compare changes of G' and G" as functions of time, and dose while the materials cure in the rheometer. Influences of light intensity, dosage application, sample thickness, and other variables are explored. Formulation compositions are compared and contrasted under controlled conditons. This paper will show how a rheological test can be interpreted to understand the physical property changes that occur during a UV curing reaction.