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Morphological Study of Nascent Growth of α‐Olefin Polymers on Spatially Unconstrained Silica Surfaces
Author(s) -
Tran Dennis,
Choi Kyu Yong
Publication year - 2018
Publication title -
macromolecular reaction engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 32
eISSN - 1862-8338
pISSN - 1862-832X
DOI - 10.1002/mren.201800009
Subject(s) - polymerization , materials science , polymer , polyethylene , polymer chemistry , post metallocene catalyst , coordination polymerization , monomer , methylaluminoxane , chain growth polymerization , polypropylene , ethylene , olefin fiber , chemical engineering , metallocene , catalysis , chemistry , solution polymerization , radical polymerization , organic chemistry , composite material , engineering
The experimental study of polymer growth on spatially unconstrained flat silica surfaces is presented for propylene and ethylene polymerization in liquid and gas phases with high activity metallocene catalyst ( rac ‐Et(Indenyl) 2 ZrCl 2 / methylaluminoxane at 30–70 °C and 30–50 psig. The study shows a surprisingly rich spectrum of nascent morphologies for each polymer synthesized in two different reaction phases. In propylene polymerization in a liquid phase, polypropylene nanofibrils are first formed at the catalyst sites and quickly develop into microglobular morphology, whereas in ethylene polymerization in a liquid phase, polyethylene nanofibrils formed at the catalyst sites grow to a ribbon‐like morphology. In gas phase polymerization where polymerization rate is much lower due to low monomer concentration, both polymers grow to compact aggregates of globules. Unlike in liquid phase polymerization, no ribbon‐like structure is formed in ethylene polymerization. The sequential polymerization of these olefin monomers has also been carried out and the experimental data show two distinct regions of corresponding polymers as observed in separate ethylene and propylene homopolymerization experiments.