Uniaxial elongational viscosity of various molten polymer composites

Uniaxial elongational viscosity of low density polyethylene (LDPE) that was filled with glass bead, glass flake, talc, or glass fiber was measured. Th e effect of various inorganic fillers on the strain-hardening property in e longational viscosity was investigated. The strain-hardening property of LD PE became weaker by the addition of fillers in the order of glass bead, gla ss flake, and talc. Class fiber filled LDPE showed a strain-softening prope rty. The smaller the particle and the larger the aspect ratio, the weaker t he strain-hardening property. Their causes were analyzed from the two terms , i.e., the relaxation spectrum and the damping function, by Bernstein-Kear sley-Zapas (BKZ) model. By the incorporation of fillers, the relaxation mod ules became larger, and the damping function became stronger in the order o f glass bead, glass flake, talc, and glass fiber. Recoverable strain was al so measured to understand weaker strain-hardening properties. The degree of recovery became smaller by the addition of fillers. It was found that the smaller the particles and the larger the aspect ratio, the smaller the degr ee of recovery. It was concluded that weaker strain-hardening properties of LDPE composite than that of LDPE are caused by stronger damping function a nd smaller degree of recovery.