In silico mechanically mediated atom transfer radical polymerization: A detailed kinetic study

Abstract

Mechanically mediated atom transfer radical polymerization (mechanoATRP) utilizing ultrasound to generate activators and improve the diffusivity of macromolecular chains is introduced as an innovative externally controlled ATRP. Herein, a comprehensive kinetic model with free volume theory based “series” encounter pair model accounting for diffusional limitations on termination, activation, and deactivation is developed for the mechanoATRP of methyl acrylate. Comparative study by using different diffusion models, for example, wp model and reduced composite kt model, as well as constant apparent kjapp model confirms the goodness of the as‐developed model. Critically, mechanochemically induced reduction rate coefficient kr,s as a key kinetic parameter is associated with experimental conditions excluding the sonication effect by a fitting equation for the first time. In silico tracking of polymer dispersity with the help of kinetic model shows a better result compared with that by the classical dispersity equation. By defining an ultrasonic factor γj, a qualitative analysis for the effect of ultrasound conditions on the diffusional limitation in mechanoATRP is presented.

Dimensional Optimization for ZnO-Based Mechano-ATRP with Extraordinary Activity

“…Compared with photomediation, the ultrasound-generated free radicals based on piezocatalysts are usually formed uniformly throughout the reaction system, avoiding the concentration gradients caused by the attenuation of light penetration . Specifically, piezoelectric ZnO nanoparticles (NPs) − and barium titanate (BTO) NPs , are able to achieve a mechanically induced electron transfer process and promote the mechano-induced polymerization.…”

“… Although the conversion of MA catalyzed by ZnO can reach 70% in the previous work, it required longer reaction time (8 h) and stronger ultrasonic power (70 W) . For the BTO system, − the conversion can reach 91% in 6 h, but more stringent conditions are required (100 W, 50 °C). The results indicated that this ZnO NRs-based system has significant advantages in monomer conversion, loading of piezocatalysts, reaction time, reaction temperature, ultrasonic power, and other aspects.…”

Playing with process conditions to increase the industrial sustainability of poly(lactic acid)-based materials

“…in which D com p,i is the center-of-mass diffusion coefficient for a macromolecule of chain length i, which in practice is considered equal to its counterpart describing the segmental contribution, 86 and D com m is the center-of-mass coefficient for the corresponding monomer, as accessible via the free volume theory (FVT [69][70][71][72] ) as highlighted in ESI. † (3) Upon inputting the scaled diffusion coefficients (eqn (2)), a (FVT-based) parallel encounter pair model 23,[69][70][71][72]87 can be used to obtain the individual apparent rate coefficients that replace pure chemical or intrinsic ones. For example, for (irreversible) termination between radicals of chain length i and j this first diffusion model implementation implies that:…”

Kinetic modeling of simultaneous polycondensation and free radical polymerization for polyurethane/poly(methyl methacrylate) interpenetrating polymer network

“…With the development of computer simulation, kinetic models have been widely used in modeling chain-growth polymerization such as free radical polymerization, [21][22][23][24][25][26][27] free radical-induced grafting and cross-linking, [28][29][30][31][32][33] and step-growth polymerization. [34][35][36][37] Unfortunately, few broadly applicable kinetic models to reveal competitive hybrid independent mechanisms are available in IPN synthesis.…”