Study on Polymer Melt Rheology Control and Polymer Processability

Abstract

Various polymer materials have been developed in accordance with requirements for high functional and high performance products in recent years. These polymer materials become useful end products through polymer processing. Linear viscoelastic rheology and non-linear rheology are dominant factors for good polymer processing. Non-linear rheology is mainly studied on several polymer melt systems by newly developed rheometers and new characterization methods in the present study. The newly developed rheometers are applied to the flow induced crystallization study and flow induced structural formation experiments in elongational flow as well as shear flow. The control methods of the non-linear rheology are proposed by molecular structure design, meso-structure design, and external field control. The degree of non-linearity, or the degree of strain hardening, of elongational viscosity can be controlled by a small amount of high molecular weight polymer, by an introduction of long chain branching, and by an addition of small particles or small solid fibers. Rheology control methods are applied to the processability of polymer processing such as high speed fiber spinning, foam processing of PP, poly(L-lactic acid) and rice, and blow molding. The new polymer processing CAE system is developed by the use of flow induced crystallization and non-linear rheology of elongational viscosity.