Facile Synthesis of Ultrahigh Molecular Weight Poly(Methyl Methacrylate) by Organic Halides in the Presence of Palladium Nanoparticles.

Ming Yuan,Panpan Zhang,Xuetao Cui,Jiaxing Lv,Lili Xu,Huadong Tang

doi:10.3390/polym12112747

Ming Yuan, Panpan Zhang + Show 4 more

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https://doi.org/10.3390/polym12112747

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Journal: Polymers	Publication Date: Nov 20, 2020
Citations: 8	License type: CC BY 4.0

Affiliation: Zhejiang University of Technology, Zhejiang University

Abstract

A facile and versatile approach for the synthesis of ultrahigh molecular weight poly(methyl methacrylate) (PMMA) at mild conditions was developed. Certain organic halides combined with a catalytical amount of palladium nanoparticles (Pd NPs) were found to be very effective in initiating polymerizations of methyl methacrylate (MMA), methyl acrylate, vinyl acetate and other vinyl monomers. An ultrahigh molecular weight PMMA with a number-average molecular weight of 4.65 × 106 Da and a weight-average molecular weight of 8.08 × 106 Da was synthesized at 70 °C using 2-bromoisobutyric acid ethyl ester (EBiB) as an initiator in the presence of catalytical amount (10.1 ppm) of Pd NPs. A kinetic investigation found that the orders of polymerization with respect to EBiB, Pd NP and MMA were 0.23, 0.50, and 0.58, respectively. Proton nuclear magnetic resonance (1H NMR) combined with matrix-assisted laser desorption ionization time of flight mass spectroscopy (MALDI-TOF) and gel permeation chromatography (GPC) were used to prove that the macromolecular chain had an end-group of EBiB residue. The electron spin resonance (ESR), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS) results reveal that the reaction of EBiB with Pd NPs caused a bromo atom (Br) transfer from EBiB to Pd NPs and resulted in the generation of EBiB residue radical to initiate the polymerization of MMA and the formation of PdIIBr2 on the surface of Pd nanoparticles.

Highlights

Poly(methyl methacrylate) (PMMA), known as acrylic glass or plexiglass, is a transparent, strong, and durable thermoplastic resin with wide applications in aircraft windshields, building windows, furniture decorations, bulletproof screens, signs and displays, sanitary wares, medical materials, LCD screens, and many other uses [1,2]
With palladium nanoparticles (Pd NPs) caused a bromo atom (Br) transfer from EBiB to Pd NPs and resulted in the generation of EBiB residue radical to initiate the polymerization of MMA and the formation of PdII Br2 on the surface of Pd nanoparticles
We found that the monodispersed Pd NPs were highly active for the polymerization of vinyl monomers such as MMA, methyl acrylate (MA), vinyl acetate (VAc) and butyl acrylate (BA) in the presence of organic halides and developed a facile and versatile approach for the synthesis of ultrahigh molecular weight

Summary

Introduction

Poly(methyl methacrylate) (PMMA), known as acrylic glass or plexiglass, is a transparent, strong, and durable thermoplastic resin with wide applications in aircraft windshields, building windows, furniture decorations, bulletproof screens, signs and displays, sanitary wares, medical materials, LCD screens, and many other uses [1,2]. The mechanic properties of PMMA have long been known to be largely dependent on its molecular weight. It is of great importance to develop a feasible and facile polymerization approach for the synthesis of ultrahigh molecular weight PMMA. PMMA with high molecular weights in the range of 105—- 106 Da [5,6,7,8,9].

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