Controlled degradation of disulfide-based epoxy thermosets for extreme environments

The burgeoning field of smart materials for oil exploration and production (E&P) demands robust polymers that remain stable in extreme conditions, but readily respond to specific chemical cues. Here, disulfide-based epoxy polymers are designed to withstand harsh, simulated oil reservoir conditions while simultaneously retaining the ability to degrade from thiol compounds. Degradable epoxy thermosets are prepared by using Bisphenol-F diglycidyl ether (BFDGE) in combination with blends of p,p'-diaminodicyclohexylmethane (PACM) and 4-aminophenyl disulfide (4APDS). These polymer systems retain their mechanical properties after exposure to extreme conditions (e.g., two weeks, 69 MPa, 100 degrees C, pH 12), but degrade in the presence of 2-mercaptoethanol (2-ME). Parameters that influence polymer degradation are detailed including temperature, concentration of disulfide groups, and monomer stoichiometry. Formulations that entirely dissolve after exposure to 2-ME are utilized further for release of prototype tracers. Disulfide-based epoxy thermosets provide a unique platform for applications in harsh environments requiring robust materials capable of on-demand degradation. (C) 2015 Elsevier Ltd. All rights reserved.