Principles of the Morphogenesis of Polyolefin Particles

In a previous paper (Grof, Z.; Kosek, J.; Marek, M. Morphogenesis model of growing polyolefin particles. AlChE J„ accepted), we have introduced the model of the morphological evolution of polyolefin particles in catalytic polymerization reactors. The model considers the polyolefin particle to consist of a large number of microelements with viscoelastic interactions acting among them. Here we present the results of the systematic mapping from the parametric space of catalyst activity, reaction conditions, mass transport resistance, and viscoelastic properties of polyolefins into the space of possible morphological developments, such as the formation of hollow particles, particles with macrocavities, regular or irregular replication of particle shape during its growth, highly porous or compact particles, the formation of fine particles, etc. The predicted particle morphologies are compared with experimental findings. We focus on the effect of temperature on the morphogenesis of polyolefin particles and identify the reaction conditions leading to the disintegration of the growing particle into fine particles, which is the unwanted phenomenon observed in industrial reactors. The causes of different pore space morphologies of Ziegler-Natta and metallocene-born polyolefin particles are also investigated.