Narrowing Molecular-Weight Distribution via Regulating the Prepolymers in Linear Polycondensation Reaction: Multiscale Simulation Study for the Case of Polyether Ether Ketone

Molecular-weight distribution (MWD) is a key factor determining
the wide spectra of polymer properties. Especially for special engineering
plastics (SEPs), experimental characterization and therefore a precise
optimization of the MWD remain a long-standing challenge. Here, we
take polyether ether ketone (PEEK) as a model system, and a multiscale
theoretical simulation strategy is developed for its synthesis procedure.
We found that controlling the MWD of prepolymers at the initial stage
is the key to the final product. Based on this understanding, we proposed
a “two-pots” strategy and a stepwise addition strategy.
Both of them are started from end-capping reactions of the prepolymers,
which can effectively reduce the dispersity (Đ) of the prepolymer and therefore that of the resulted final PEEK
products. The resulting Đ from both proposed
strategies are much lower than the conventional one-pot process. We
believe that both strategies can enable the customized optimization
of the MWD for polymers synthesized from polycondensation reactions.