Cure profiles, crosslink density, residual stresses, and adhesion in a model epoxy

The influence of network chemical composition and cure conditions in a model epoxy system was investigated. Addition of 1,4-butanediol to a bisphenol-F epoxy resin cured with 4-methyl-2-phenyl imidazole led to a decrease in the modulus and glass transition temperature, which resulted in lower residual stresses. Moisture uptake increased with the addition of 1,4-butanediol and is associated with an increase in the free volume of the epoxy. However, even with greater moisture uptake, the addition of 1,4-butanediol to the epoxy increased its adhesion to quartz, primarily through lower residual stress in the samples and increased energy dissipation on debonding. Differences in residual stress for different cure conditions were not measurable in these systems. However, increasing the cure time increased the adhesion of the epoxy to quartz.