(31g) Short-Chain Branching and Rheology of Crystallizing LLDPEs
- Conference: AIChE Annual Meeting
- Year: 2021
- Proceeding: 2021 Annual Meeting
- Group: Materials Engineering and Sciences Division
- Time: Sunday, November 7, 2021 - 5:15pm-5:30pm
We first show that LLDPEs with different SCB exhibit dissimilar rheology in the crystallizing melts, as measured by rheo-Raman experiments. Using the slip-link model, the differences in rheology are interpreted as different fractions of bridging and dangling chains in the uncrystallized portion of a partially crystallized entangled polymer fluid. For crystallizing LLDPEs, the model implies different crystalline structures, which are consistent with expectations from SCB distribution. We then incorporate experimentally-measured comonomer content distribution and molecular weight distribution and their cross-correlations explicitly into the slip-link model. When applied to the rheo-Raman measurements, this refined slip-link model explicitly connects the SCB distribution to the rheology and network structure of crystallizing LLDPEs. This model offers a more detailed perspective on the relationship between molecular structure and product performance for LLDPE materials.