Effect of Operating Conditions on Dynamic Crystallization of Ethylene/1-Octene Copolymers
N, Chokputtanawuttilerd, . 2013
Dynamic crystallization (DC) is a new characterization technique for measuring the chemical composition distribution (CCD) of semicrystalline copolymers. This technique fractionates polymers based on chain crystallizabilities under a constant cooling rate; a solvent is also fed through the column at a constant flow rate during the crystallization to enhance the physical separation of the polymer fractions. In this work, a DC model for ethylene/1-olefin copolymers on the basis of population balance, crystallization kinetics, and axial dispersion is proposed. This model is found to describe the experimental DC profiles of an ethylene/1-octene copolymer at various operation conditions very well.
Polyolefins made with Ziegler–Natta catalysts have non-uniform distributions of molecular weight (MWD) and chemical composition (CCD). The MWD is usually measured by high-temperature gel…
Heterogeneous Ziegler-Natta catalysts produce polyolefins that have broad distributions of molecular weight (MWD) and chemical composition (CCD).
Temperature rising elution fractionation (TREF) and crystallization analysis fractionation (CRYSTAF) fractionate semicrystalline polymers according to their crystallizabilities from dilute…