Magnesium alkoxide precursor to Ziegler-Natta catalyst - emphasis on morphology studies through computer vision approach

MgCl۲ supported Ti catalyst is used in commercial propylene polymerization process. Morphology is a key performance determination parameter for polymer resins produced by commercial olefin polymerization process. Higher resin flowability and bulk density (greater than ۰.۳۸g/cc) are demonstrated by ‘good’ morphological resins (sphericity close to ‘۱’). Polymer resin morphology is controlled by morphology of the catalyst used as well as polymerization conditions. The industrially accepted approaches to control polymer resin morphology are by controlling catalyst morphology through various approaches like pre-polymerization of the catalysts. Morphology of the catalyst is dependent on precursor (support) morphology and process parameters for making the catalyst. In this work, we have developed magnesium alkoxide precursor, a Ziegler-Natta catalyst using the precursor and studied its performance in gas phase propylene polymerization process. Further, morphology of different precursor and catalyst samples is evaluated and correlated it using a “computer vision” based approach. The approach involves modeling the circularity (as an analog of sphericity) of a catalyst and precursor particle. It is observed that the circularity of catalyst particles is lower than that of precursor, due to attrition in the process. It is also reflected in increase in particle size distribution span from ۰.۸۳ to ۱.۳۲ while synthesis of catalyst from precursor. This approach provides a tool to evaluate and screen the catalysts for using in polymerization.

Keywords:

morphology , computer vision , catalyst , Polymer , resin