The effect of moisture on the mechanical behavior of a nylon‐epoxy adhesive

The mechanical properties of a commercial nylon‐epoxy resin have been studied using a sensitive creep apparatus which employs a frictionless levitation magnetic bearing. Isothermal creep measurements over a temperature range of 30‐170°C and covering a time scale of five decades were made on the wet and dry state of the material. Following the usual time‐temperature reduction scheme, master curves for each state were constructed from the experimental data. The effect of moisture was found to be more than that of a simple plasticizer. The steepness of the reduced curves in the transition region was determined and the distribution function of retardation times of the two states of the sample were calculated. The problem of predicting the physical state of the bulk adhesive at higher temperatures was found to be complicated, possibly due to the presence of nylon crystallites.