scholarly journals One-Pot Preparation of Metal–Polymer Nanocomposites in Irradiated Aqueous Solutions of 1-Vinyl-1,2,4-triazole and Silver Ions

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4235
Author(s):  
Alexey A. Zezin ◽  
Alexey A. Zharikov ◽  
Artem I. Emel’yanov ◽  
Alexander S. Pozdnyakov ◽  
Galina F. Prozorova ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Monomer Concentration ◽  
Gel Permeation Chromatography ◽  
Silver Ions ◽  
Polymer Nanocomposite ◽  
Molar Ratio ◽  
One Pot ◽  
Radiation Chemical ◽  
Vis Spectroscopy ◽  
Metal Polymer

Metal–polymer nanocomposite polyvinyltriazole–silver nanoparticles were obtained using one-pot synthesis in irradiated aqueous solutions of 1-vinyl-1,2,4-triazole (VT) and silver ions. Gel permeation chromatography data show that upon radiation initiation, the molecular weight of poly(1-vinyl-1,2,4-triazole) increases with increasing monomer concentration. To study the kinetics of polymerization and the features of the radiation–chemical formation of nanoparticles, UV-Vis spectroscopy was used. TEM images show a relatively small average size of the forming nanoparticles (2–3 nm) and a narrow size distribution, which shows the effective stabilization of nanoparticles by triazole substituents at a molar ratio of VT and silver ions of 25/1. The addition of ethyl alcohol was used to increase the efficiency of synthesis and suppress the crosslinking of macromolecules in solution. The results of the work show that aqueous–alcoholic solutions of 1 wt.% VT can be used to obtain soluble nanocomposite materials. 10 wt.% monomer solutions have prospects for use in the preparation of polymer gels filled with nanoparticles.

scholarly journals The effect of the polar solvents on the synthesis of poly(urethane-urea-siloxane)s

2012 ◽  
Vol 77 (10) ◽  
pp. 1457-1481 ◽  
Author(s):  
Milica Balaban ◽  
Vesna Antic ◽  
Marija Pergal ◽  
Iolanda Francolini ◽  
Andrea Martinelli ◽  
...  
Keyword(s):  
Monomer Concentration ◽  
Gel Permeation Chromatography ◽  
Molar Ratio ◽  
Solvent Ratio ◽  
Solvent Mixtures ◽  
Scanning Calorimetry ◽  
Experimental Conditions ◽  
Water Contact ◽  
Soft Segments ◽  
Hard Segments

Segmented poly(urethane-urea-siloxanes) (PUUS) based on 4,4?- methylene diphenyl diisocyanate-ethylene diamine (MDI-ED) hard segments and hidroxypropyl-terminated poly(dimethylsiloxane) (PDMS, M n =1000 g mol-1) soft segments were prepared under various experimental conditions. The copolymers with constant molar ratio of hard and soft segments (PDMS:MDI:ED = 1:2:1; 20 wt. % of the hard segments) were synthesized in two different solvent mixtures, by two-step polyaddition procedure. The first one was THF/DMAc with different co-solvent ratio (1/1, 1/2 and 1/9, v/v), whereas the second one was THF/NMP (1/9, v/v). The reaction conditions were optimized by varying the co-solvents ratio, the concentration of the catalyst, the initial monomer concentration, as well as the time of the first and the second step of reaction. The effect of the experimental conditions on the size of PUUS was investigated by gel permeation chromatography (GPC) and viscometry of the dilute solutions [?]. The copolymers with the highest molecular weights were obtained in the THF/NMP mixture (1/9, v/v). The structure and composition of the copolymers were determined by 1H NMR and FTIR spectroscopy. The morphology of the synthesized copolymers was investigated by atomic force microscopy (AFM), while the thermal properties were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The surface properties were evaluated by measuring the water contact angle (WCA). The copolymers showed phase separated microstructure and were stable up to 200?C in nitrogen.

Novel Amphiphilic Star-Shaped Poly(2-Oxazoline)s with Calix[4]Arene Branching Center

2021 ◽  
Vol 899 ◽  
pp. 300-308
Author(s):  
Aleksei N. Blokhin ◽  
Alla B. Razina ◽  
Andrey V. Tenkovtsev
Keyword(s):  
Aqueous Solutions ◽  
Ring Opening ◽  
Gel Permeation Chromatography ◽  
Ring Opening Polymerization ◽  
Arene Derivative ◽  
Vis Spectroscopy ◽  
Gel Permeation ◽  
Grafting From ◽  
Cationic Ring Opening Polymerization

Novel amphiphlic four-arm star-shaped poly (2-alkyl-2-oxazoline) s with calix [4] arene core were synthesized using the “grafting from” approach. The chlorosulfonated calix [4] arene derivative was synthesized and successfully applied as a multifunctional initiator for the cationic ring-opening polymerization of 2-alkyl-2-oxazolines. Obtained star-shaped poly (2-alkyl-2-oxazoline) s were characterized by means of NMR, UV-Vis spectroscopy and gel-permeation chromatography. It was shown that star-shaped poly (2-isopropyl-2-oxazoline) perform thermosensitivity in aqueous solutions.

scholarly journals A feasible synthetic strategy for three-armed star poly(ester amine) via Michael addition polymerization

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Wei Yang ◽  
Cai-Yuan Pan
Keyword(s):  
Molecular Weight ◽  
Michael Addition ◽  
Monomer Concentration ◽  
Gel Permeation Chromatography ◽  
Molar Ratio ◽  
Glycol Diacrylate ◽  
H Nmr ◽  
Synthetic Strategy ◽  
Addition Polymerization ◽  
Feed Molar Ratio

AbstractThree-armed star-shaped poly(ester amine) was synthesized by Michael addition polymerizations of equal molar ratio of ethylene glycol diacrylate (EGDA) and piperazine (PZ) in the presence of a small amount of multifunctional monomer, 1,3,5-triacryloylhexa-hydro-1,3,5-triazine (TT) in CHCl3. When the polymerization proceeded almost completely, the molecular weight of the polymers formed were determined by the feed molar ratio of difunctional monomer to multifunctional monomer, and the molecular weight distribution (Mw/Mn) approached the theoretical value (Mw/Mn =1+1/f). The mechanism of the polymerization was investigated by 1H NMR and Gel permeation chromatography (GPC). The monomer concentration and the molar ratio of difunctional monomers/multifunctional monomer played an important role in the polymerization.

scholarly journals Copolymers based on N-acryloyl-L-leucine and urea methacrylate with pyridine moieties

2016 ◽  
Vol 81 (3) ◽  
pp. 307-322 ◽  
Author(s):  
Emil Buruiana ◽  
Mioara Murariu
Keyword(s):  
Experimental Data ◽  
Gel Permeation Chromatography ◽  
Specific Rotation ◽  
Optically Active ◽  
Molar Ratio ◽  
Carboxyl Group ◽  
Thermal Methods ◽  
Vis Spectroscopy ◽  
Gel Permeation ◽  
Copolymer Poly

By using free radical polymerization of (N-methacryloyloxyethyl-N?-4-picolyl)-urea (MAcPU) and N-acryloyl-L-leucine (AcLeu), an optically active copolymer, poly[(N-methacryloyloxyethyl-N?-4-picolyl)-urea-co-N-acryloyl-L-leucine], MAcPU-co-AcLeu (1.86:1 molar ratio) was prepared and subsequently functionalized at the pyridine-N with (1R/S)-(?/+)-10-camphorsulfonic acid (R/S-CSA) and at carboxyl group with (R)-(+)-?-ethylbenzylamine (R-EBA) or trans-4-stilbene methanol (t-StM). The structures, chemical composition and chiroptical activity of the monomers and the copolymers were characterized by spectral analysis (FTIR, 1H (13C)-NMR, 1H,1H-COSY, UV/vis), thermal methods (TGA, DSC), fluorescence spectroscopy, gel permeation chromatography and specific rotation measurements. Influence of the optical activity of monomer and modifier on modified copolymers suggested a good correlation between the experimental data obtained (23[?]589=+12.5? for AcLeu and MAcPU-co-AcLeu, 23[?]589=0?+27.5? for (MAcPU-co-AcLeu)-R/S-CSA, 23[?]589=+25? for (MAcPU-co-AcLeu)-R-EBA, and 23[?]589 = 0? for (MAcPU-co-AcLeu)-St). In addition, the photobehavior of the stilbene copolymer (MAcPU-co-AcLeu)-St in film was investigated by UV-vis spectroscopy. The fluorescence quenching of the stilbene species in the presence of aliphatic/aromatic amine in DMF solution was evaluated, more efficiently being 4,4??dipyridyl (detection limit: 7.2 x 10-6 mol/L).

scholarly journals The Effect of pH on the Size of Silver Nanoparticles Obtained in the Reduction Reaction with Citric and Malic Acids

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5444
Author(s):  
Lukasz Marciniak ◽  
Martyna Nowak ◽  
Anna Trojanowska ◽  
Bartosz Tylkowski ◽  
Renata Jastrzab
Keyword(s):  
Silver Nanoparticles ◽  
Citric Acid ◽  
Malic Acid ◽  
Silver Ions ◽  
Reduction Reaction ◽  
Heating Time ◽  
Molar Ratio ◽  
Vis Spectroscopy ◽  
Wide Ph Range ◽  
Average Size

In colloidal methods, the morphology of nanoparticles (size and shape) as well as their stability can be controlled by changing the concentration of the substrate, stabilizer, adding inorganic salts, changing the reducer/substrate molar ratio, and changing the pH and reaction time. The synthesis of silver nanoparticles was carried out according to the modified Lee and Meisel method in a wide pH range (from 2.0 to 11.0) using citric acid and malic acid, without adding any additives or stabilizers. Keeping the same reaction conditions as the concentration of acid and silver ions, temperature, and heating time, it was possible to determine the relationship between the reaction pH, the type of acid, and the size of the silver nanoparticles formed. Obtained colloids were analyzed by UV-Vis spectroscopy and investigated by means of Transmission Electron Microscope (TEM). The study showed that the colloids reduced with citric acid and malic acid are stable over time for a minimum of seven weeks. We observed that reactions occurred for citric acid from pH 6.0 to 11.0 and for malic acid from pH 7.0 to 11.0. The average size of the quasi-spherical nanoparticles changed with pH due to the increase of reaction rate.

Electrospun nanofibrous membranes of cellulose acetate containing hydroxyapatite co-doped with Ag/Fe: morphological features, antibacterial and degradation of methylene blue from aqueous solutions

2021 ◽  
Author(s):  
Ahmed Esmail Shalan ◽  
M. Afifi ◽  
M.M. El-Desoky ◽  
M.k Ahmed
Keyword(s):  
Methylene Blue ◽  
Aqueous Solutions ◽  
Cellulose Acetate ◽  
Morphological Features ◽  
Molar Ratio ◽  
Electrospinning Technique ◽  
Nanofiber Membranes ◽  
Nanofibrous Membranes ◽  
Co Doped

Cellulose acetate nanofiber membranes containing hydroxyapatite co-doped with Ag/Fe were efficaciously attained through the electrospinning technique. Different molar ratio compositions of hydroxyapatite co-doped with Ag/Fe in the structure of the...

scholarly journals Investigations of ternary complexes of Co(II) and Ni(II) with thiodiacetate anion and 1,10-phenanthroline or 2,2’-bipyridine in aqueous solutions

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Dariusz Wyrzykowski ◽  
Joanna Pranczk ◽  
Dagmara Jacewicz ◽  
Aleksandra Tesmar ◽  
Bogusław Pilarski ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Substitution Reactions ◽  
Experimental Conditions ◽  
Kinetic Measurements ◽  
Hydroxo Complexes ◽  
Binary Complexes ◽  
Vis Spectroscopy ◽  
Potentiometric Titration Method ◽  
The Stability ◽  
Ph Range

AbstractA potentiometric titration method (PT) and a stopped-flow kinetic technique monitored by a UV−Vis spectroscopy have been used to characterize the stability of series of Co(II)- and Ni(II)-thiodiacetato complexes, M(TDA), in the presence of 1,10-phenanthroline (phen) or 2,2’-bipyridine (bipy) in aqueous solutions. The stability constants of the binary (1:1), ternary (1:1:1) as well as the resulting hydroxo complexes were evaluated and compared to the corresponding oxydiacetate complexes. Based on the species distribution as a function of pH the relative predominance of the species in the system over a pH range was discussed. Furthermore, the kinetic measurements of the substitution reactions of the aqua ligands to phen or bipy in the coordination sphere of the binary complexes M(TDA) were performed in the 288–303 K temperature range, at a constant concentration of phen or bipy and at seven different concentrations of the binary complexes (0.2–0.5 mM). The kinetic stability of the M(TDA) complexes was discussed in relation to the experimental conditions and the kind of the auxiliary ligands (phen/bipy). Moreover, the influence of the type of primary ligand (thiodiacetate/oxydiacetate) on the substitution rate of the auxiliary ligands was also compared.

One-pot synthesis of double silane-functionalized carbon dots with tunable emission and excellent coating properties for WLEDs application

2021 ◽  
Author(s):  
Wenbing Cao ◽  
Yuhan Wu ◽  
Xin Li ◽  
Xuanfeng Jiang ◽  
Yuhong Zhang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Carbon Dots ◽  
Great Influence ◽  
Alkoxy Group ◽  
Color Temperature ◽  
Molar Ratio ◽  
Coating Properties ◽  
One Pot ◽  
Light Emitting ◽  
Light Emitting Devices

Abstract Silane-functionalized carbon dots (SiCDs) can be exploited as effective color converting materials for the solid-state light-emitting devices. However, most of SiCDs reported thus far have shown photoluminescence emissions in the blue and green spectral range, which limit them to construct an efficient white light-emitting diodes (WLEDs) due to the lack of long-wavelength emission. Herein, a series of double silane-functionalized carbon dots (DSiCDs) were prepared via a one-step solvothermal method. The results show that the organic functional group of the silane has great influence on the optical properties of DSiCDs and the number of alkoxy group in the silane has great influence on coating properties of DSiCDs. In addition, the DSiCDs prepared by (3-aminopropyl)triethoxysilane and N-[3-(Trimethoxysilyl)propyl]ethylenediamine with molar ratio of 7:3 show excellent optical properties with the maximum emission at 608 nm under 400 nm excitation. Furthermore, they can be completely dried within 1 h at room temperature to form fluorescent coating with high stability and strong adhesion to the substrate. Together with their excellent optical and coating properties, they can be directly coated on LED chips to prepare WLEDs, with a CIE coordinate of (0.33,0.31), color rendering index of 81.6, and color temperature of 5774 K.

Sign in / Sign up

Export Citation Format

Share Document