Dielectrometer Monitored Adhesive Bonding.

摘要

An automatic dielectrometer was investigated as a means for monitoring the cure of a structural adhesive during an in-press bonding operation. The instrument was found to be sensitive to changes occurring within the adhesive,as indicated by relative values of the dielectric constant and the dissipation factor,during the bonding of metallic adherends. Insulation and shielding techniques were developed to obtain relatively noise-free dielectrometer traces while operating in the electrically noisy environment of a heated platen,hydraulic press. Definitive curves were obtained on both an epoxy type and a polyimide type adhesive system under a constantly increasing temperature cure cycle. These traces were used to design an experiment to determine the effect upon resultant-joint strength of varying the point at which full bonding pressure was applied to polyimide adhesive bonded tensile lap shear joints. (Author)