Anionic living polymerization of alkyl methacrylate at ambient temperature and its mechanism research

Abstract

In order to break through the bottleneck of anionic polymerization, polar monomers such as methyl methacrylate (MMA), ethyl methacrylate, butyl methacrylate, and hexyl methacrylate are subjected to anionic polymerization at room temperature in tetrahydrofuran (THF) using potassium tert-butoxide (t-BuOK) as the initiator. The polymerization of alkyl methacrylates is studied by multidetector gel permeation chromatography, proton nuclear magnetic resonance ( 1 H-NMR) and 13 C-NMR spectroscopy, and dynamic laser light scattering. It is found that t-BuOK can initiate the living anionic polymerization of polar alkyl methacrylate, and the polymerization conversion almost reaches up to 100%. t-BuOK exists into two kinds of agglomerates, whose hydrodynamic volumes are 10 and 80 nm, respectively. t-BuOK in THF is similar to emulsion and has a critical active species concentration of about 0.0265 mol L −1 and does not depend on how much t-BuOK is added. After the initiation of the polymerization, the large agglomerates of a loose and less regular structure that have occupied the main part of t-BuOK are greatly reduced, but they do not continue to decrease until they disappear according to the equilibrium theory. Similarly, the active chain after initiation also will not aggregate again. Furthermore, t-BuOK also has an active species with smaller average vibration size between cation and anion pairs, which can only initiate the polymerization of MMA with rather slow rate but cannot initiate other alkyl methacrylates. At last, because t-BuOK can make the dormant species caused by side reactions to be revived, the anionic polymerization of MMA could obtain a high yield.

Electron-Beam Irradiation of Cinnamate Films Affords Nanoscale Patterned Substrates for Use in Devices and as Scaffolds in Tissue Engineering

“…C4 was reisolated. To investigate the influence of negative charges on the monomer, anionic polymerizations were carried out under different conditions [potassium tert-butoxide (KO t Bu), 26 potassium graphite, and solvated electrons by using 18-crown-6 to chelate K + ] with varying concentrations. With KO t Bu, only small molecular decomposition products for C4 were observed via gel permeation chromatography.…”

Electron Energy Loss Processes in Methyl Methacrylate: Excitation and Bond Breaking

“…These show an indisputable role of transient negative ions in the process induced by interaction with secondary low-energy electrons and decay via release of CH 3 neutral radicals and polymer scission . Anions are well-known to activate polymerization reactions in various precursors, including acrylates. − For MMA, anion-induced polymerization was explored in clusters upon electron transfer, , showing that the cationic counterion can significantly enhance the process . It is therefore generally accepted that low-energy electrons do play an important role in the PMMA modification.…”

Kinetic modeling study of the group-transfer polymerization of alkyl crotonates using a silicon Lewis acid catalyst

“…Furthermore, the requirement of such low temperatures severely limits the application of GTP to industrial processes. 16,17 The construction of a kinetic model is an effective approach toward the development of efficient and manageable polymerization systems that operate at high temperatures. The kinetic model quantitatively demonstrates the elementary reactions and provides useful knowledge related to the polymerization mechanism and design of optimum polymerization systems.…”