Toward More Universal Prediction of Polymer Solution Viscosity for Solvent-Based Recycling

The viscosity of polymer solutions is important for both
polymer
synthesis and recycling. Polymerization reactions can become hampered
by diffusional limitations once a viscosity threshold is reached,
and viscous solutions complicate the cleaning steps during the dissolution–precipitation
technique. Available experimental data is limited, which is more severe
for green solvents, justifying dedicated viscosity data recording
and interpretation. In this work, a systematic study is therefore
performed on the viscosity of polystyrene solutions, considering different
concentrations, temperatures, and conventional and green solvents.
The results show that for the shear rate range of 1–1000 s–1, the solutions with concentrations between 5 and
39 wt % display mainly Newtonian behavior, which is further confirmed
by the applicability of the segment-based Eyring-NRTL and Eyring-mNRF
models. Moreover, multivariate data analysis successfully predicts
the viscosity of polystyrene solutions under different conditions.
This approach will facilitate future data recording for other polymer–solvent
combinations while minimizing experimental effort.