Novel Ni/pHEMA-gr-PVP Composites Obtained by Polymerization with Simultaneous Metal Deposition: Structure and Properties

Abstract

The synthesis and study of metal-containing hydrogels, particularly those filled with nickel nanoparticles, is currently of interest to many researchers. This paper presents the results of an investigation of the structure and properties of Ni(0)-filled composites on the basis of 2-hydroxyethylmethacrylate copolymers (HEMA) with polyvinylpyrrolidone (PVP) and their hydrogels. The authors of the article are the first who propose the method to produce these materials by combining the processes of polymer matrix synthesis and a reduction of Ni2+ ions. Synthesis is carried out in one stage without complicated equipment and is technologically simple. It is determined by thermometric research that the temperature conditions required for the chemical reduction of Ni2+ are achieved due to the heat released during the exothermic reaction of HEMA polymerization in the presence of PVP. With the help of Fourier transform infrared analysis, and thermogravimetric and differential-thermal analysis, the formation of a crosslinked graft copolymer based on HEMA and PVP was confirmed, and its structural parameters, including the efficiency of PVP grafting, PVP content in the copolymer, and the molecular weight of the interstitial fragment of the polymer network, were investigated. The results obtained with scanning electron microscopy revealed that the size of the Ni(0) particles is about 500 nm. X-ray structural analysis of the composites obtained confirmed the existence of metal nickel particles. The strength, elastic, sorption, electrical, and magnetic properties of the obtained composites in the solid (dry) and elastic (swollen) physical states, depending on the composition of the copolymer and the content of the metal filler, have been investigated.

Features of Structure and Properties of pHEMA-gr-PVP Block Copolymers, Obtained in the Presence of Fe2+

“…When adding metal salts with variable oxidation state to HEMA/PVP composition, the π-complex with participation of PVP, HEMA and Me n+ is formed. ( Scheme 1 b) [ 33 , 60 ]. The interaction occurs in the coordination sphere of the metal ion, which is accompanied by a significant weakening of the π-bond in the monomer.…”

“…In addition, the IR spectrum of the copolymer showed a significant decrease in the intensity of the characteristic PVP band in the range of 1372 cm −1 , which indicates wagging vibrations of the CH 2 –CH bond of polyvinylpyrrolidone, and proves the participation of tertiary carbon of PVP in the grafting reaction [ 60 ].…”

“…The surface hardness of dry samples (with diameters Ø 12 ± 0.1 mm and height h = 5 ± 0.01 mm) was found according to the conic yield point in a Höppler consistometer at 293 °K by pressing a steel cone with a vertex angle of 58°08′ into a polymeric specimen under a load of 5.0 kg for 60 s [ 60 ].…”

Green Synthesis of Silver Nanoparticles by Low-Energy Wet Bead Milling of Metal Spheres

“…In Figure 3, the probability distribution of particle diameters is reported for different groups of capping agents. The curves in the upper left plot (a) refer to three different molecular weights of PVP, whose properties as stabilizer, grafting agent [31], and size-orienting component have been amply recognized and investigated in the literature, both for Ag and for different zerovalent NPs made of non-transition elements [32]. It can be seen that the smallest average particles diameters for non-ionic dispersants are obtained for PVP 10k, namely in the case of shorter polymer chains.…”

Hydrogen Sulfide Adsorption by Iron Oxides and Their Polymer Composites: A Case-Study Application to Biogas Purification

“…A first attempt consisted of realizing a pellet comprising a polybutadiene spherical core coated by a layer of sorbent located only at the surface of such an organic matrix. Such method, producing a pellet capable of adsorbing only superficially, was discarded in favor of a more reliable and proven technique relying upon mixing Fe 2 O 3 with PVA as a binder, which was chosen for the following favorable features: the hydroxyl groups present in the molecular structure of PVA can interact with metal oxides/hydroxides by hydrogen bonds, thus enhancing the binding strength between active adsorbent and organic substrate whose reciprocal affinity is a basic parameter in polymer composites [ 36 ]; PVA is insoluble in nonpolar solvents and it is soluble in water, thus allowing the preparation of aqueous solutions of controlled density and viscosity without resorting to toxic or expensive organic solvents; PVA itself is biocompatible and biodegradable under aerobic and anaerobic conditions. Such characteristics make it largely used in environmentally sound materials for a wide range of applications [ 37 ].…”