Ethylene/1-olefin copolymers synthesized with multiple-site-type catalytic systems typically exhibit broad molecular weight distribution (MWD) and chemical composition distribution (CCD). These microstrucral characteristics can be described by the presence of several active site types, each of which produces chains with distinct chain microstructures. In this work, a new approach to identify the number of active site types and chain microstructures produced on each active site type was developed based on simultaneous deconvolution of the bivariate MWD/CCD information. Chain microstructures produced on each active site type are assumed to follow Stockmayer's bivariate distribution. The proposed approach was validated with simulated data of model ethylene/1-butene and ethylene/1-octene copolymers.
Ethylene/1‐olefin copolymers made with multiple‐site‐type catalytic systems typically have broad molecular weight distribution (MWD) and chemical composition distribution (CCD) because each site type produces polymer chains with distinct average chain microstructures. In this work, the simultaneous deconvolution of MWD and CCD was investigated to identify the number of site types and chain microstructures made on each site type. Four strategies based on different data sources were tested using the MWD and CCD simulated for an ethylene/1‐butene copolymer made with a catalyst having five site types. Our results indicate that the simultaneous deconvolution of the complete bivariate MWD and CCD is the best approach to describe the complete microstructure of the model ethylene/1‐butene copolymers.
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