Polypropylene (PP) random copolymers are an important class of commercial materials that can be tuned for a wide range different applications. The structure–property relations mainly discussed in this article focusing on two major influencing factors, the catalyst system and type amount comonomer. Ziegler–Natta (ZN) systems still dominate production polypropylene todays sixth-generation ZN cata...

An improved model for the production of polypropylene in a gas phase fluidized bed reactor was developed. Comparative simulation studies were carried out using the well-mixed, constant bubble size and the improved models. The improved model showed different prediction characteristics of polymer production rate as well as heat and mass transfer behavior as compared to other published models. All...

We have performed a statistical analysis using broad band IRAS data on about 500 planetary nebulae with the aim of characterizing their dust content. Our approach is different from previous studies in that it uses an extensive grid of photoionization models to test the methods for deriving the dust temperature, the dust-to-gas mass ratio and the average grain size. In addition, we use only dist...

Activity limiting agents (ALA) are used to avoid thermal runaway during the gas phase polymerization of propylene.