(415b) Molecular Architecture Effects on Polymer Viscoelasticity: An Expansion of the Van Gurp Palmen Methodology

The van Gurp-Palmen plot (vGP) [1] was originally proposed to verify the validity of Time-Temperature Superposition (TTS). It was found to be sensitive to polymer molecular weight, polydispersity, and structure, hence providing a new tool for the study of polymer chain dynamics. In the current work [2], we show that the use of the vGP plot gives deeper insight into chain dynamics than has been currently thought. By compiling literature data for polymer melts with different topological structures: linear (pure and blend), ring, comb, and bottlebrush we expand the vGP approach through identification of a new parameter: the reciprocal of complex modulus at the first minimum moving from the terminal regime and compared this with the steady-state recoverable compliance. The results show that the two paramters, while showing some similarities in behavior, e.g., they follow similar dependences on the molecular weight, weight fraction of high molecular weight content and backbone concentration, there are also differences. The work we shown here expands the application of vGP plot and provides new insights into understanding polymer dynamics. Of particular interest is the novel findings for ring topology polymers where we find that literature reports of high degree of freedom of linear contaminants are probably over-stated.

[1] M. van Gurp and J. Palmen, "Time-temperature superposition for polymeric blends," Rheology Bulletin, 67 (1998) 5–8.

[2] Z. Qian and G.B. McKenna, "Expanding the application of the van Gurp-Palmen plot: New insights into polymer melt rheology," Polymer, 155 (2018) 208-217.