How we can improve ARGET ATRP in an aqueous system: Honey as an unusual solution for polymerization of (meth)acrylates

I. Zaborniak, P. Chmielarz, How we can improve ARGET ATRP in an aqueous system: Honey as an unusual solution for polymerization of (meth)acrylates, European Polymer Journal, Volume 183, 2023, 111735, ISSN 0014-3057, https://doi.org/10.1016/j.eurpolymj.2022.111735. (https://www.sciencedirect.com/science/article/pii/S001430572200739X) Abstract: Aqueous solutions of various types of honey as a source of reducing sugars – glucose and fructose, were used to accelerate or control activators regeneration by electron transfer atom transfer radical polymerization (ARGET ATRP) in a homogeneous or heterogeneous environment. The aqueous or alcoholic-aqueous solution was applied for the polymerization of hydrophilic methacrylates i.e. 2-(dimethylamino)ethyl methacrylate (DMAEMA), glycidyl methacrylate (GMA), 2-hydroxyethyl methacrylate (HEMA), while the polymerization of a hydrophobic monomer – n-butyl acrylate (nBA) was conducted in miniemulsion under ion-pair and interfacial catalysis. The polymerization of DMAEMA in a honey solution accelerated the polymerization rate up to 30-fold with a significant improvement in the control over the structure of the product, namely, the polymers were characterized by narrow molecular weight distribution (Mw/Mn = 1.33), and initiation efficiency up to 98 %. Controlled polymerization of nBA was conducted in a honey-contained miniemulsion. Honey-based miniemulsion was successfully checked for the synthesis of both linear and branched polymers. The use of chemical reducing agents found in commercially available food products for polymerization is an economic concept that eliminates the need for high purity laboratory reagents, moreover, food products are widely available and therefore much cheaper. The proposed concept has great potential for industrial applications. Keywords: Honey; Reducing sugars; ARGET ATRP; Aqueous environment; Miniemulsio

How we can improve ARGET ATRP in an aqueous system: Honey as an unusual solution for polymerization of (meth)acrylates

<p>The data includes raw analysis data: gel permeation chromatography (GPC), nuclear magnetic resonance spectroscopy (NMR) to determine monomer conversion and confirm the structure of the final products, gravimetric analysis to determine monomer conversion, dynamic light scattering (DLS) of the miniemulsion that served as the medium reaction in polymer synthesis.</p&gt

Ultrasound-Mediated Atom Transfer Radical Polymerization (ATRP)

Ultrasonic agitation is an external stimulus, rapidly developed in recent years in the atom transfer radical polymerization (ATRP) approach. This review presents the current state-of-the-art in the application of ultrasound in ATRP, including an initially-developed, mechanically-initiated solution with the use of piezoelectric nanoparticles, that next goes to the ultrasonication-mediated method utilizing ultrasound as a factor for producing radicals through the homolytic cleavage of polymer chains, or the sonolysis of solvent or other small molecules. Future perspectives in the field of ultrasound in ATRP are presented, focusing on the preparation of more complex architectures with highly predictable molecular weights and versatile properties. The challenges also include biohybrid materials. Recent advances in the ultrasound-mediated ATRP point out this approach as an excellent tool for the synthesis of advanced materials with a wide range of potential industrial applications

Stimuli-Responsive Rifampicin-Based Macromolecules

This paper presents the modification of the antibiotic rifampicin by an anionic polyelectrolyte using a simplified electrochemically mediated atom transfer radical polymerization (seATRP) technique to receive stimuli-responsive polymer materials. Initially, a supramolecular ATRP initiator was prepared by an esterification reaction of rifampicin hydroxyl groups with α-bromoisobutyryl bromide (BriBBr). The structure of the initiator was successfully proved by nuclear magnetic resonance (1H and 13C NMR), Fourier-transform infrared (FT-IR) and ultraviolet–visible (UV-vis) spectroscopy. The prepared rifampicin-based macroinitiator was electrochemically investigated among various ATRP catalytic complexes, by a series of cyclic voltammetry (CV) measurements, determining the rate constants of electrochemical catalytic (EC’) process. Macromolecules with rifampicin core and hydrophobic poly (n-butyl acrylate) (PnBA) and poly(tert-butyl acrylate) (PtBA) side chains were synthesized in a controlled manner, receiving polymers with narrow molecular weight distribution (Mw/Mn = 1.29 and 1.58, respectively). “Smart” polymer materials sensitive to pH changes were provided by transformation of tBA into acrylic acid (AA) moieties in a facile route by acidic hydrolysis. The pH-dependent behavior of prepared macromolecules was investigated by dynamic light scattering (DLS) determining a hydrodynamic radius of polymers upon pH changes, followed by a control release of quercetin as a model active substance upon pH changes

A new protocol for ash wood modification : synthesis of hydrophobic and antibacterial brushes from the wood surface

The article presents the modification of ash wood via surface initiated activators regenerated by electron transfer atom transfer radical polymerization mediated by elemental silver (Ag(0) SI-ARGET ATRP) at a diminished catalyst concentration. Ash wood is functionalized with poly(methyl methacrylate) (PMMA) and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) to yield wood grafted with PMMA-b-PDMAEMA-Br copolymers with hydrophobic and antibacterial properties. Fourier transform infrared (FT-IR) spectroscopy confirmed the covalent incorporation of functional ATRP initiation sites and polymer chains into the wood structure. The polymerization kinetics was followed by the analysis of the polymer grown in solution from the sacrificial initiator by proton nuclear magnetic resonance ((1)H NMR) and gel permeation chromatography (GPC). The polymer layer covalently attached to the wood surface was observed by scanning electron microscopy (SEM). The hydrophobic properties of hybrid materials were confirmed by water contact angle measurements. Water and sodium chloride salt aqueous solution uptake tests confirmed a significant improvement in resistance to the absorption of wood samples after modification with polymers. Antibacterial tests revealed that wood-QPDMAEMA-Br, as well as wood-PMMA-b-QPDMAEMA-Br, exhibited higher antibacterial activity against Gram-positive bacteria (Staphylococcus aureus) in comparison with Gram-negative bacteria (Escherichia coli). The paper presents an economic concept with ecological aspects of improving wood properties, which gives great opportunities to use the proposed approach in the production of functional hybrid materials for industry and high quality sports equipment, and in furniture production

Induction of Oxidative Stress in SH-SY5Y Cells by Overexpression of hTau40 and Its Mitigation by Redox-Active Nanoparticles

Abnormally phosphorylated tau protein is the principal component of neurofibrillary tangles, accumulating in the brain in many neurodegenerative diseases, including Alzheimer’s disease. The aim of this study was to examine whether overexpression of tau protein leads to changes in the redox status of human neuroblastoma SH-SY5Y cells. The level of reactive oxygen species (ROS) was elevated in tau-overexpressing cells (TAU cells) as compared with cells transfected with the empty vector (EP cells). The level of glutathione was increased in TAU cells, apparently due to overproduction as an adaptation to oxidative stress. The TAU cells had elevated mitochondrial mass. They were more sensitive to 6-hydroxydopamine, delphinidin, 4-amino-TEMPO, and nitroxide-containing nanoparticles (NPs) compared to EP controls. These results indicate that overexpression of the tau protein imposes oxidative stress on the cells. The nitroxide 4-amino-TEMPO and nitroxide-containing nanoparticles (NPs) mitigated oxidative stress in TAU cells, decreasing the level of ROS. Nitroxide-containing nanoparticles lowered the level of lipid peroxidation in both TAU and EP cells, suggesting that nitroxides and NPs may mitigate tau-protein-induced oxidative stress