Polymer Engineering and Science, Vol.50, No.8, 1646-1657, 2010
Separating Stress and Time Dependent Effects in the Temperature Dependent Creep of Polyethylene Nanocomposites
The nonlinear time dependent creep of linear-low density polyethylene (LLDPE) reinforced with montmorillonite layered silicate was investigated. A previous study related the time/stress dependence of creep compliance of the material at room temperature using the Burger and Kohlrausch-Williams-Watts models. Using both the creep and recovery compliance curves, we employ the Schapery formulation to study the relationship between deformation, time, stress, and temperature of LLDPE nanocomposites. Smooth master-curves are constructed using time-temperature-stress superposition principles. The stress and temperature-related creep constants and shift factors were determined for the material using the Schapery nonlinear viscoelastic equation. The prediction results confirm the enhanced creep resistance of nanofillers even at extended time scales and low temperatures. POLYM. ENG. SCI., 50:1646-1657, 2010. (C) 2010 Society of Plastics Engineers