A new class of long chain branched isotactic polypropylene (LCBPP) polymers with high molecular weights and well-controlled structures are prepared via a combination of roc-Me2Si(2-Me-4-Ph-lnd)ZrCl2/MAO catalyst and a T-reagent, such as p-(3-butenyl)styrene. The T-reagent can simultaneously serve two functions (comonomer and chain transfer agent) during metallocene-mediated propylene polymerization in the presence of a small amount of hydrogen. 1H NMR and SEC equipped with triple detectors revealed most of polymer chain containing LCB structure. LCBPPs displayed a systematic increase in zero-shear viscosity and Arrhenius flow activation energy as branch density increased. LCBPPs with high branch point density displayed thermorheologically complex behavior, and strain hardening was observed in extensional flow.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Organic Chemistry
- Polymers and Plastics
- Materials Chemistry