Location: JHE 326H
Branched architectures are desired whenever a polymer must be subjected to extensional deformations during melt processing. A preferred synthetic route for introducing branching to polypropylene (PP) involves solvent-free reactive extrusion, wherein polyfunctional coagents such as triallyl trimesate (TAM) are activated with alkyl peroxides at elevated temperature. Using this methodology, linear PP materials are transformed by radical-mediated chain scission and coagent-induced crosslinking, the balance of which dictates the resulting molecular weight distribution and the polymer microstructure.
New insight into coagent-mediated PP transformations has been gained by characterizing model compounds and polymer derivatives. Knowledge of the structure and yields of coagent-derived products is integrated with molecular weight distribution data and rheological measurements to develop a more complete understanding of the reactions that contribute to PP branching, as well as the influence of branching on rheological properties. This presentation will summarize our advances in this area.
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