Propylene polymerization reactions with supported Ziegler–Natta catalysts: Observing polymer material produced by a single active center |
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| Authors: | Yury V Kissin Vladimir P Marin Patricia J Nelson |
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| Institution: | 1. Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Rd, Piscataway, New Jersey;2. W. R. Grace & Co, 10001 Chemical Rd, Pasadena, Texas;3. BASF, Iselin Research Center, 101 Wood Ave, Iselin, New Jersey |
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| Abstract: | Medium‐ and high‐resolution SEM analysis of several Ti‐based MgCl2‐supported Ziegler–Natta catalysts and isotactic polypropylene produced with them is carried out. Each catalyst particle, 35–55 μ in size, produces one polymer particle with an average size of 1.5–2 mm, which replicates the shape of the catalyst particle. Polymer particles contain two distinct morphological features. The larger of them are globules with Dav ～400 nm; from 1 to 2 × 1011 globules per particle. Each globule represents the combined polymer output of a single active center. The globules consist of ～2500 microglobules with an average size of ～20 nm. The microglobules contain several folded polymer molecules; they are the smallest thermodynamically stable macromolecular ensembles in propylene polymerization reactions. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3832–3841 |
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| Keywords: | differential scanning calorimetry (DSC) DSC analysis electron microscopy poly(propylene) (PP) polypropylene SEM analysis Ziegler– Natta catalysts Ziegler– Natta polymerization |
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