Poly(methyl methacrylate-co-2-hydroxyethyl methacrylate) Four-arm Star Functional Copolymers by Quasiliving ATRP: Equivalent Synthetic Routes by Protected and Nonprotected HEMA Comonomers

Abstract

Comprehensive investigations were carried out on the synthesis of well-defined poly(methyl methacrylate-co-2-hydroxyethyl methacrylate) P(MMA-co-HEMA) copolymers, i. e PMMA with predetermined average number of pendant hydroxyl functionalities, by using HEMA and trimethylsilyl-protected HEMA (TMS-EMA) under quasiliving ATRP conditions by a tetrafunctional initiator and CuCl/2,2'-bipyridyl(bpy) catalyst system in methanol at 10 o C. It was found that these two synthetic routes, that is the direct and protected approaches, are equivalent in terms of yields, hydroxyl functionality and molecular weight distribution (MWD). Bulk copolymerization of MMA and HEMA by ATRP led to broad multimodal MWD in contrast to copolymers with narrow MWD in the presence of methanol. A two-step purification method applying silica-alumina chromatography followed by treatment with an acidic ion-exchange resin, used also as the deprotecting agent, was found to provide copolymers free of catalyst contamination. At higher monomer conversions, GPC analyses indicate the occurrence of chainchain coupling by recombination of the macroradicals resulting in lower than theoretical apparent initiating efficiencies. According to the results on the effect of reaction time on monomer conversion, relatively short reaction times, less than 2 hours, are sufficient to obtain high yields and PMMA with desired functionalities and MW under the applied ATRP conditions. The resulting four-arm star hydroxyl-functional P(MMA-co-HEMA) copolymers offer a variety of new possibilities for the preparation of a variety of novel PMMA-based macromolecular architectures.2

Modeling of the Atom Transfer Radical Copolymerization Processes of Methyl Methacrylate and 2-(Trimethylsilyl) Ethyl Methacrylate under Batch, Semibatch, and Continuous Feeding: A Chemical Reactor Engineering Viewpoint

“…Figure C shows that the initial monomer molar ratio and instantaneous copolymer composition are in good agreement for each case, as has been verified by Szanka et al , The gradient in MMA composition along the polymer chain is not obvious, and thus the total variation range of instantaneous MMA composition ( F A ) is <10%. In particular, at a molar ratio of 75:25 for MMA to HEMA-TMS, the copolymers almost have uniform composition along the chain.…”

Modeling of the ATRcoP Processes of Methyl Methacrylate and 2‐(Trimethylsilyl) Ethyl Methacrylate in Continuous Reactors: From CSTR to PFR

“…When under the constant value of P e (50), the variation ranges of F A are 12–29%, 46–52%, and 71–76% for [ M A ]/([ M A ] + [ M B ]) = 25, 50, and 75%, respectively, showing that F A and the proportion of MMA in feeding flow are in good agreement. The obtained results are in accordance with those shown in some other work . The composition of spontaneous copolymers produced by tubular reactor is mainly influenced by the reactivity ratios of two kinds of monomers .…”

Retinol derivative as bioinitiator in the synthesis of hydroxyl-functionalized polymethacrylates for micellar delivery systems

“…Herein, we report the synthesis of two series of amphiphilic copolymers based on 2-hydroxyethyl methacrylate (HEMA). It is well known that linear, graft, and cross-linked polymers [21,22] or peptide/ polymer conjugates [23] based on HEMA are attractive biomaterials for contact lenses, gene and drug delivery [24]. The biocompatible HEMA/MMA copolymers [25][26][27][28] have been extended by polymethacrylate segment with PEG grafts [29], grafted from the surface of TiO 2 nanoparticles [30], or modified to Fe 3 O 4 containing nanocomposite pH-responsive systems for anticancer drug delivery [31].…”