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

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1956 ◽  
Author(s):  
Oleksandr Grytsenko ◽  
Ivan Gajdoš ◽  
Emil Spišák ◽  
Volodymyr Krasinskyi ◽  
Oleh Suberlyak
Keyword(s):  
Chemical Reduction ◽  
Structural Parameters ◽  
Polymer Network ◽  
Exothermic Reaction ◽  
Infrared Analysis ◽  
Structure And Properties ◽  
Electrical And Magnetic Properties ◽  
Metal Filler ◽  
Nickel Particles ◽  
Heat Released

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.

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

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4580
Author(s):  
Oleksandr Grytsenko ◽  
Ludmila Dulebova ◽  
Oleh Suberlyak ◽  
Volodymyr Skorokhoda ◽  
Emil Spišák ◽  
...  
Keyword(s):  
Original Composition ◽  
Structural Parameters ◽  
Polymer Network ◽  
Surface Hardness ◽  
Crosslinking Density ◽  
Iron Sulfate ◽  
Structure And Properties ◽  
Ion Permeability ◽  
Crosslinking Degree ◽  
Copolymer Structure

This paper presents the research results of the copolymer structure and properties of 2-hydroxyethylmethacrylate (HEMA) with polyvinylpyrrolidone (PVP) and their hydrogels, obtained by block polymerization in the presence of iron sulfate (II). By the methods of chemical analysis, IR spectroscopy, Thermogravimetric (TG) and Differential Thermal Analysis (DTA), the course of grafted copolymerization of HEMA on PVP with the formation of a cross-linked copolymer was confirmed. The results received by scanning electron microscopy showed that due to the copolymerization of HEMA with PVP, macroporous hydrogels with a pore size of 10–30 μm were obtained. The peculiarities of the structure formation of the obtained copolymers depending on the initial composition formulation were established and their structural parameters were investigated: PVP grafting efficiency, PVP content in copolymer, molecular weight of internodal fragment of polymer network, crosslinking degree, and crosslinking density. The interrelation of sorption–diffusion, physical–mechanical and thermophysical properties along with the structure of the obtained materials was proved. It was shown that with the increasing PVP content in the original composition, the efficiency of its grafting and crosslinking density of the polymer network decreased, but the surface hardness, heat resistance, sorption capacity of copolymers in the dry state, as well as ion permeability and elasticity in the swollen state increased, while their tensile strength deteriorated. It is proved that by changing the original composition formulation it is possible to change the structure and hence the properties of the copolymers in the desired direction.

scholarly journals Synthesis of Pt-Ni/CNT Cathodic Catalyst and its Application in a PEM fuel Cell

2021 ◽  
Vol 65 (1) ◽  
Author(s):  
D. M. López-Rosas ◽  
R.M. Félix-Navarro ◽  
J. R. Flores-Hernández ◽  
C. Silva-Carrillo ◽  
I. L. Albarrán-Sánchez ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Chemical Reduction ◽  
Proton Exchange ◽  
Nickel Particles ◽  
Spray Technique ◽  
Galvanic Displacement Reaction ◽  
Exchange Membrane ◽  
Cathodic Catalyst

Abstract. This work reports the synthesis, characterization, and catalytic activity of Pt-Ni/CNT with a low platinum load to use as cathode electrocatalyst in PEMFC (proton-exchange membrane fuel cells). The synthesis of nickel particles on the carbon nanotubes surface was carried out by chemical reduction of a Ni(ethylenediamine) complex; after that, the galvanic displacement reaction was performed to platinum deposition onto Ni/CNT. The Pt-Ni/CNT was deposited by spray technique on a gas diffuser layer (GDL) and subsequently subjected to several potential cycles to promote Ni atoms migration. Finally, its catalytic activity was evaluated in a fuel cell.   Resumen. En este trabajo, se reporta la síntesis, caracterización y evaluación catalítica del electrocatalizador Pt-Ni/CNT con bajo contenido de platino, empleado como electrocatalizador catódico en una celda de combustible tipo PEMFC (Celda de combustible de membrana de intercambio protónico). La síntesis de las partículas de níquel sobre la superficie de los nanotubos de carbono se llevó a cabo mediante la reducción química del complejo de Ni(etilendiamina) y posteriormente, se depositó platino sobre el material Ni/CNT mediante la reacción de desplazamiento galvánico. Se depositó una película de Pt-Ni/CNT sobre un difusor de gas mediante la técnica de esprayado y posteriormente fue sometido a diversos ciclos de potencial para promover la migración de los átomos de níquel y evaluar su actividad catalítica en una celda de combustible.

Structure and properties of polystyrene-polyethylene interpenetrating polymer network (ipn)-like systems

1994 ◽  
Vol 83 (1) ◽  
pp. 147-156 ◽  
Author(s):  
Eberhard Borsig ◽  
Agnesa Fiedlerová ◽  
Karl G. Häusler ◽  
Goerg H. Michler ◽  
Roberto Greco
Keyword(s):  
Polymer Network ◽  
Interpenetrating Polymer Network ◽  
Structure And Properties

scholarly journals Studies of Formation Mechanism, Structure, and Properties of Network Copolymers Obtained by Cocuring of Rolivsan Thermosetting Resins with Aromatic Diamines

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
B. A. Zaitsev ◽  
L. G. Kleptsova ◽  
I. D. Shvabskaya
Keyword(s):  
Glass Transition ◽  
High Temperature ◽  
Thermal Analyses ◽  
Polymer Network ◽  
Three Dimensional ◽  
Transition Temperatures ◽  
Structure And Properties ◽  
Aromatic Diamines ◽  
Thermosetting Resins ◽  
Glass Transition Temperatures

Rolivsan thermosetting resins (ROLs) demonstrate high glass-transition temperatures and excellent processability. In our work, high-temperature properties of ROLs were significantly improved using a novel technique for structural and chemical modification of microheterogeneous network polymers. This technique involves, among other procedures, cocuring of rolivsan resins with aromatic diamines (ADA). The most noticeable increase in storage moduli and glass transition temperatures (Tg) of these copolymers was achieved when ROLs were modified with 10-15 wt.% of ADA and the resulting blends were subjected to thermal treatment in air in the temperature range 180 to 320°C for several hours. FTIR, 13С NMR spectroscopy, and dynamic mechanical and thermal analyses were used for studying the structure and properties of the obtained products. It was demonstrated that the mechanism of formation of ROL-ADA copolymers includes the following high-temperature reactions: (i) three-dimensional radical copolymerization of unsaturated ROL components and (ii) cleavage of heat-sensitive methacrylate crosslinking units inside the polymer network. The second process is accompanied by formation of pending units of methacrylic acid and methacrylic anhydride, which participate in condensation reactions with ADA.

Self-propagating high-temperature synthesis of the SiC

1986 ◽  
Vol 1 (2) ◽  
pp. 275-279 ◽  
Author(s):  
Osamu Yamada ◽  
Yoshinari Miyamoto ◽  
Mitsue Koizumi
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Exothermic Reaction ◽  
Experimental System ◽  
Ignition Process ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Effect Of Particle Size ◽  
Constituent Elements ◽  
Heat Released

Self-propagating high-temperature synthesis (SHS), also called combustion synthesis, is useful for fabricating numerous ceramics. In the case of SiC, heat released from the exothermic reaction is not sufficient to completely convert the mixed reactants of constituent elements into SiC in the usual nonadiabatic experimental system. This disadvantage could be overcome by a new ignition process called, the “direct passing method of electric current.” By using this method, stoichiometric fine SiC powder could be obtained rapidly and efficiently with low electric power. This paper also involves the effect of particle size of Si and C initial reactant powders on conversion efficiency into SiC and also on particle size of SiC powder fabricated by this method.

scholarly journals A Guide through the Dental Dimethacrylate Polymer Network Structural Characterization and Interpretation of Physico-Mechanical Properties

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4057 ◽  
Author(s):  
Izabela Maria Barszczewska-Rybarek
Keyword(s):  
Mechanical Properties ◽  
Chemical Structure ◽  
Structural Parameters ◽  
Polymer Network ◽  
Polymer Networks ◽  
Impact Resistance ◽  
Organic Matrices ◽  
Dental Restorative

Material characterization by the determination of relationships between structure and properties at different scales is essential for contemporary material engineering. This review article provides a summary of such studies on dimethacrylate polymer networks. These polymers serve as photocuring organic matrices in the composite dental restorative materials. The polymer network structure was discussed from the perspective of the following three aspects: the chemical structure, molecular structure (characterized by the degree of conversion and crosslink density (chemical as well as physical)), and supramolecular structure (characterized by the microgel agglomerate dimensions). Instrumental techniques and methodologies currently used for the determination of particular structural parameters were summarized. The influence of those parameters as well as the role of hydrogen bonding on basic mechanical properties of dimethacrylate polymer networks were finally demonstrated. Mechanical strength, modulus of elasticity, hardness, and impact resistance were discussed. The issue of the relationship between chemical structure and water sorption was also addressed.

scholarly journals An in situ SAXS investigation of the formation of silver nanoparticles and bimetallic silver–gold nanoparticles in controlled wet-chemical reduction synthesis

2020 ◽  
Vol 2 (1) ◽  
pp. 225-238 ◽  
Author(s):  
Paulo R. A. F. Garcia ◽  
Oleg Prymak ◽  
Viktoria Grasmik ◽  
Kevin Pappert ◽  
Wagner Wlysses ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Online Monitoring ◽  
Chemical Reduction ◽  
Structural Parameters ◽  
Nanoparticle Synthesis ◽  
Small Particles ◽  
Metallic Nanoparticle ◽  
Wet Chemical

In situ investigation of metallic nanoparticle synthesis with an online monitoring of the system by SAXS. Determination of structural parameters and growth processes. Ag-NP synthesis presented a bimodal system with the presence of small particles (∼3 nm).

Synthesis and Consolidation of Nano-Sized NiCo Powder by Powder Technology Rout

2007 ◽  
Vol 561-565 ◽  
pp. 1425-1428 ◽  
Author(s):  
W.M. Daoush
Keyword(s):  
Composite Powder ◽  
Chemical Reduction ◽  
Average Particle Size ◽  
Complexing Agent ◽  
Average Particle ◽  
Chemical Reduction Method ◽  
Homogeneous Microstructure ◽  
Electrical And Magnetic Properties ◽  
Saturation Induction ◽  
Metallic Salt

Nano sized Co-20wt%Ni composite powder was synthesized by electroless chemical reduction method using metallic salt precursors and hypophosphite as a reducing agent in alkaline tartarate bath as a complexing agent. The synthesized powder provide better sinterability, mechanical, electrical and magnetic properties with homogeneous microstructure. The nano-sized powder could be obtained, which have the average particle size of 40 nm, with a saturation magnetization (Bs ) of 97.95 which was increased by heat treatments of powder in hydrogen to 127 emu/g due to the exclusion of the precipitated phosphrous in the composite powder. The powder underwent cold compaction at 600 Mpa and sintering at 1050 oC for 30 min. The saturation induction for the sintered material of 149.3 emu/g higher than the synthesized powder and has electrical resistivity value of 7.6 μcm.

Structure and Properties of High Performance Gels Made by Module Assembling Method

2012 ◽  
Vol 1418 ◽  
Author(s):  
Mitsuhiro Shibayama ◽  
Hanako Asai ◽  
Kenta Fujii ◽  
Yuki Akagi ◽  
Takamasa Sakai
Keyword(s):  
High Performance ◽  
Preparation Method ◽  
Polymer Network ◽  
Polymer Networks ◽  
Uniform Structure ◽  
Structure And Properties ◽  
Mechanical Measurements ◽  
High Performance Polymer ◽  
Ion Gels ◽  
Intensity Functions

ABSTRACTHigh performance polymer network gels consisting of tetra-arm poly(ethyleneglycol) (Tetra-PEG) gels were fabricated via a module assembling method and their mechanical properties and structure were investigated by stretching and compression measurements, dynamic mechanical measurements, and small-angle neutron scattering (SANS). It was found that Tetra-PEG gels are nearly-ideal polymer network with negligible fractions of defects and entanglements. SANS intensity functions indicated that the network structure was uniform free from spatial inhomogeneities. It is deduced that this uniform structure is ascribed to its unique preparation method, i.e., module assembling method (cross-end-coupling of tetra-functional macromers with complementary functional groups). Characteristic properties originated from the near-ideality as polymer networks are demonstrated, including its application to ion gels, i.e., polymer network in ionic liquid.

Structure and Properties Enhancement in High-Speed Steels upon Primary Solidification of a Melt

2008 ◽  
Vol 144 ◽  
pp. 267-272
Author(s):  
Alexander S. Chaus
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Chemical Elements ◽  
Structural Parameters ◽  
Structure Refinement ◽  
Structure And Properties ◽  
Theoretical Evaluation ◽  
Surface Active ◽  
The Impact ◽  
Toughness Enhancement

In order to exhibit good all-round performance the impact toughness enhancement of cast high-speed steels (HSS) is obligatorily needed. In general, different methods are used commercially to achieve cast structure refinement and, as a consequence, their properties are improved. Introduction into the melt of inoculants particles or surface-active additions is among most beneficial. However, the effect of modifying additions in cast HSS has been studied insufficiently. For this reason the theoretical evaluation and experimental confirmation of the modifying and refining effects of 23 chemical elements in HSS have been carried out. The relationships between the structural parameters and mechanical properties in the M2 and T30 HSS have been established.

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