“Living” Polymer Dispersity Quantification for Nitroxide-Mediated Polymerization Systems by Mimicking a Monodispersed Polymer Blending Strategy

Abstract

The quantification of dispersity is an indispensable part of characterizing polymers. In this work, general dispersity equations for “living” polymers obtained by nitroxide-mediated polymerization (NMP), reflecting the contribution of dead polymeric chains to the overall dispersity, are presented. Derivation of new dispersity equations is inspired by the monodispersed polymer blending strategy, which is confirmed by experimental data in accordance with a Gaussian distribution. The accuracy and applicability of the newly derived equations are validated by comparative studies with those by the conventional equations through an in silico simulation benchmark and experimental data gathered from literature studies. Moreover, the dissociation and combination reaction rate coefficients are also successfully estimated by the combination of kinetic and as-developed dispersity equations under actual polymerization conditions. The new dispersity equations can be used as dispersity modulation tools in combination with the Gaussian distribution function and can also be effective tools beyond the experimentation to predict accurate dispersity for living polymers and to estimate rate coefficients.

The challenges of controlling polymer synthesis at the molecular and macromolecular level

“…86,[95][96][97] Circumventing the need for optimising synthesis parameters, polymer blends tailor molecular weight distributions by superimposing a basis set of distributions. [98][99][100] A challenge in this space is minimising the size of basis distribution sets required to make specific distributions.…”

Development and Experimental Validation of a Dispersity Model for In Silico RAFT Polymerization

“…Explicit quantitative models for dispersity are attractive due to their ease of use, open accessibility, no need for high-performance PCs, and the ability to code into a range of software packages. Zhu and co-workers derived dispersity as a composite equation for RDRP comprising a living step, transfer steps, and terminative steps. , Currently, only full equations for normal ATRP and NMP have been derived (Table ) by employing blend and block theory. For ATRP and NMP, activation/deactivation effects dominate during the initial stages of the polymerization, where chains are relatively short, but it is commonly speculated that terminative events become more significant during the later stages, where the polymer chains are much longer. ,, Work simulating the molecular weight distributions for ATRP, RAFT, and cationic polymerizations based on the first three terms of the dispersity equation that exist in the literature have been fitted to experimental data to provide information about the control .…”

On the Precise Determination of Molar Mass and Dispersity in Controlled Chain-Growth Polymerization: A Distribution Function-Based Strategy

“…Further, distribution functions are also utilized in depolymerization kinetic investigations . In addition, the model-based design of MMD is a promising and versatile strategy to manipulate polymer MMDs, − in which the (log)­normal distribution is a useful framework to accurately approximate the SEC traces in a log-scaled coordinate for the polymers obtained through different controlled chain-growth polymerizations. − …”