Dual-Cure Networks Designed for Property Modulation via High-Energy Radiation [* Cross-Reference *]

Motivated by the need to develop FGAs with well-defined and stable gradients in properties, a new approach is proposed involving the use of thermal/ionizing radiation dual-cure adhesives. To generate adhesives with dual-cure characteristics, a series of epoxy resin formulations containing a reactive liquid rubber-based additive that is rich in unsaturation have been developed.

Networks are thermally cured and then subjected to γ irradiation, and their capacity to undergo secondary crosslinking reactions is examined via chemical, thermal, and mechanical characterization. While the addition of large concentrations of liquid rubber additives can result in an initial reduction in properties such as modulus and glass transition temperature, their addition can significantly boost radiation sensitivity, enabling the realization of large, well-controlled variations in properties as a function of radiation dose.