Uniaxial elongational viscosity of various molten polymer composites

Abstract

AbstractUniaxial elongational viscosity of low density polyethylene (LDPE) that was filled with glass bead, glass flake, talc, or glass fiber was measured. The effect of various inorganic fillers on the strain‐hardening property in elongational viscosity was investigated. The strain‐hardening property of LDPE became weaker by the addition of fillers in the order of glass bead, glass flake, and talc. Glass fiber filled LDPE showed a strain‐softening property. The smaller the particle and the larger the aspect ratio, the weaker the strain‐hardening property. Their causes were analyzed from the two terms, i.e., the relaxation spectrum and the damping function, by Bernstein‐Kearsley‐Zapas (BKZ) model. By the incorporation of fillers, the relaxation modules became larger, and the damping function became stronger in the order of glass bead, glass flake, talc, and glass fiber. Recoverable strain was also 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 degree of recovery. It was concluded that weaker strain‐hardening properties of LDPE composite than that of LDPE are caused by stronger damping function and smaller degree of recovery.