Simulation of temperature effect on the structure control of polystyrene obtained by atom-transfer radical polymerization

Abstract

SbstractThis paper uses a new kinetic modeling and simulations to analyse the effect of temperature on the polystyrene properties obtained by atom-transfer radical polymerization (ATRP). Differently from what has been traditionaly published in ATRP modeling works, it was considered "break" reactions in the mechanism aiming to reproduce the process at high temperatures. Results suggest that there is an upper limit temperature (130 °C), above which the polymer architecture loses the control. In addition, for the system considered in this work, the optimum operating temperature was 100 °C, because at this temperature polymer with very low polydispersity index is obtained, at considerable fast polymerization rate. Therefore, this present paper provides not only a tool to study ATRP processes by simulations, but also a tool for analysis and optimization, being a basis for future works dealing with this monomer and process.

Modeling of 1,3‐Butadiene Solution Polymerizations Catalyzed by Neodymium Versatate

“…Based on the previous discussion, this might already be expected, and it is probably related to the higher initial loads of monomer and the more efficient feed of catalyst, as already discussed. Higher reactor temperatures favor higher rates of polymerization, but also provide higher dispersities, leading to production of smaller chains due to higher rates of chain transfer reactions [37]. One possible cause for the increase of dispersity might also be the presence of multiple catalyst sites; however, the existence of multiple catalyst sites usually leads to multimodal molar mass distributions, which have not been observed in the present study, in spite of the shoulders located at large chain sizes of the molar mass distributions for runs L1 and L2 as shown in Fig.…”

An Experimental and Computational Approach on Controlled Radical Photopolymerization of Limonene

“…Surely, this result is the most distant from ideality. In a controlled polymerization, the molar mass profile increases linearly with the conversion, [47,48] according to the simulation profile. In contrast, in a conventional polymerization, the average molar mass increases a lot at the beginning of the process and decreases as the monomer conversion increases.…”

Tuning the molecular weight distribution from atom transfer radical polymerization using deep reinforcement learning

“…We select styrene ATRP as our simulation system. Simulation of styrene ATRP may be done by solving the ATRP chemical kinetics ordinary differential equations (ODEs) in Table 1, (Weiss et al, 2015;Preturlan et al, 2016;Vieira & Lona, 2016b;Li et al, 2011) by method of moments, (Zhu, 1999) or by Monte Carlo methods. (Al-Harthi et al, 2006;Najafi et al, 2010;Turgman-Cohen & Genzer, 2012;Payne et al, 2013;Toloza Porras et al, 2013) This work directly solves the ODEs because this allows accurate track-ing of the concentration of individual polymer chains while being more computationally efficient than Monte Carlo methods.…”

“…This assumption does not bias the nature of ATRP qualitatively and has been practiced in almost all previous ATRP simulation research. (Weiss et al, 2015;Preturlan et al, 2016;Vieira & Lona, 2016b;Li et al, 2011;Vieira et al, 2015) In some of our simulations, we altered the rate constants by up to ±30% to account for possible inaccuracies in the measurement of these values and other unpredictable situations such as turbulence in the reactor temperature. We employed the VODE (Brown et al, 1989;Byrne & Hindmarsh, 1975;Hindmarsh & Byrne, 1977;Hindmarsh, 1983;Jackson & Sacks-Davis, 1980) integrator implemented in SciPy 0.19 using a maximum internal integration step of 5000, which is sufficient to achieve final MWDs with high accuracy.…”