Simulation of Molecular Weight Distributions Obtained by Pulsed Laser Polymerization (PLP): New Analytical Expressions Including Intramolecular Chain Transfer to the Polymer

Abstract

A new approach for the simulation of PLP (pulsed laser polymerization) is presented. This approach allows one to obtain new analytical solutions for different polymerization schemes, including either chain transfer to the monomer or intramolecular chain transfer to the polymer. The first results of the simulation of PLP experiments on n‐butyl acrylate at 20 °C and ambient pressure are presented.MWDs simulated for PLP of n‐butyl acrylate, in bulk at 20 °C and ambient pressure using three models: the model with intramolecular chain transfer to the polymer (solid line), the model with chain transfer to monomer (dashed line), and the classical model (dotted line).imageMWDs simulated for PLP of n‐butyl acrylate, in bulk at 20 °C and ambient pressure using three models: the model with intramolecular chain transfer to the polymer (solid line), the model with chain transfer to monomer (dashed line), and the classical model (dotted line).

Propagation Rate Coefficient and Fraction of Mid‐Chain Radicals for Acrylic Acid Polymerization in Aqueous Solution

“…These chain-end radicals may transform into MCRs during the dark-time period in between two pulses. As the backbiting rate coefficient is relatively small (%200 s À1 for butyl acrylate at ambient temperature [13] ) and is supposed to have a fairly high activation energy (%29 kJ Á mol À1 ), [11] the formation of MCRs in the time period between two laser at low and high LPRRs, respectively. [14] It has been pointed out in ref.…”

“…As the MCR species is poorly propagating and poorly terminating as compared to the SPR, backbiting is not only a source for short-chain branches, which may be determined by 13 C NMR (see e.g., ref. [15] ), but also has a major impact on polymerization kinetics.…”

The role of mid‐chain radicals in acrylate free radical polymerization: Branching and scission

“…Without this correlation in place, the PLP-SEC experiment cannot yield accurate results and the characteristic PLP structure imprinted on the molecular weight distribution is destroyed. 32,64 Figure 3 demonstrates the influence of an increasing backbiting rate on the structure of the molecular weight distribution. The simulation is based on a relatively simple model which nevertheless shows the effect.…”

“…Qualitatively very similar simulations can be found in the literature. 32,64 In the herein employed model, end-chain propagating acrylate radicals undergo a backbiting reaction with a certain rate and subsequently start repropagation with a significantly reduced propagation rate, k MCR p . Chain termination events of MCRs are not considered in the model.…”

The Effect of Intramolecular Transfer to Polymer on Stationary Free‐Radical Polymerization of Alkyl Acrylates, 3 – Consideration of Solution Polymerization up to High Conversions

“…This conclusion is based on numerous experimental [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] and theoretical [18][19][20][21][22][23][24] investigations. According to these investigations, the mechanism of the intermolecular chain transfer reaction is a 1,5-hydrogen shift that occurs through a six-membered ring structure.…”