A modified power law model for the steady shear viscosity of polystyrene melts

✍ Scribed by Gregory A. Campbell; Mary Elizabeth Adams

• Publisher: Society for Plastic Engineers
• Year: 1990
• Tongue: English
• Weight: 767 KB
• Volume: 30
• Category: Article
• ISSN: 0032-3888
• DOI: 10.1002/pen.760301005

✦ Synopsis

Abstract

An engineering equation that describes the steady shear viscosity of polystyrene melts is developed as an extension of the well known power law model for non‐Newtonian viscosity. The parameters in the equation have been related to weight and number averaged molecular weights and temperature. The model is tested on data for both narrow and broad molecular weight polystyrenes whose properties span most materials of commercial importance. This equation predicts the melt viscosity‐shear rate behavior for both narrow and broad distribution polystyrenes from knowledge of weight and number averaged molecular weights and temperature. Our analysis directly yields shift factors for the shear rate and viscosity axes. Therefore, no secondary calculations are necessary to generate master curves for polystyrenes. The shift factors are related to weight and number averaged molecular weights of the polystyrenes and temperature of the melt.