Abstract
Chemical shrinkage in thermosetting polymers drives residual stress development and induces residual
deformation in composite materials. Accurate characterization of chemical shrinkage during curing is
therefore vital to minimize residual stresses through process modeling and optimize composite
performance. This work introduces a novel methodology to measure the pre- and post-gelation chemical
shrinkage of an epoxy resin using three-dimensional digital image correlation (3D-DIC). Differential
scanning calorimetry (DSC) is employed to calculate reaction kinetics and correlate chemical shrinkage
with the degree of cure. Rheology experiments are conducted to quantify gelation and validate post-gelation.
3D-DIC post-gelation results show excellent agreement with rheology. Pre-gelation results show the effect
of the in-situ curing in the proximity of constraints on the global strain behavior. This work introduced an innovative approach to characterize the chemical shrinkage of thermosets during curing, which will enable
accurate residual stress prediction for enhancing thermoset composite performance and provide insight into
the in-situ polymer behavior during processing.