On-site PhD conferral Huaqin Yang
Supervisor: Prof. dr. Sanjay Rastogi
Co-supervisor: Dr. Dario Romano , King Abdullah University of Science and Engineering, Jaddah, Saudi Arabia
Keywords: polyethylene, topological constraints, entanglement, polymerization
"Topological constraints and the role of polymerization conditions"
The properties of polymers are significantly related to its macromolecular structure. Polyethylene, one of the common used plastics, having the simplest repeat unit -CH2-CH2-, is a semi-crystalline polymer. Within its non-crystalline region, there are some topological constraints, entanglements, homogeneously distributed. These topological constraints play a key role in the respect of polymer processing and properties. Recently, our research group unveiled the heterogeneous distribution of these entanglements in the non-crystalline domain. This research focuses on tailoring these entanglements in the non-crystalline domain using homogeneous catalysis and understand their equilibration process (reversible decomposing into separate elements) upon melting. Reduction of these topological constraints allows the synthesis of unequilibrated polymers, revealing new dynamics during melt equilibration. Heterogeneization (formation of separate elements into new subgroup) of the homogeneous catalysts and its influence on the entanglement formation is also addressed. The resulting heterogeneously distributed entanglements synthesized using the heterogeneous catalysis allows the solid-state processing of otherwise intractable polymer to highly performing tapes.