Study on extensional viscosity of acrylic adhesive

In this paper, transient extensional viscosities of acrylic adhesives were studied using Extensional Viscosity Fixture (EVF) in rotation rheometer at 120 °C under different extensional rates. Extensional viscosity is an important parameter to evaluate extensional behavior of adhesives. Strain hardening was observed during extension for tested adhesives. Effects of molecular weight and tackifi er addition on transient extensional viscosities were also investigated. Addition of tackifier would decrease transient extensional viscosities of tested acrylic adhesives. In addition, extensional viscosities were compared to complex viscosities obtained from linear oscillation shear tests at 120 °C. Extensional viscosity is more sensitive to addition of tackifier compared to shear viscosity.