The effect of long-term recovery and storage on the mechanical response of ductile poly(urethane) coatings

Abstract

The scope of this work has been to investigate storage and recovery processes in ductile polymer coatings. The effects of storage have been measured in terms of variations in mechanical response with time. The use of contact tests in combination with sophisticated surface imaging tools offered unique possibilities to monitor deformation recovery over long periods of time. The kinetics of the recovery processes has been monitored. Polyurethane coatings were found to recover in a similar fashion to a viscous liquid. By comparing the time scale of the recovery with transient tests, it was evident that this was not a viscoelastic effect. The effect of exposure to water and humidity on deformation response and recovery was significant for polyurethane coatings. In addition, high amounts of pigmentation had a great effect on recovery processes. Surface-, bulk-, and interfacial-properties were greatly affected by storage time.