scholarly journals Oxidative polymerization of acrylamide in the presence of thioglycolic acid

2005 ◽  
Vol 3 (4) ◽  
pp. 705-720 ◽  
Author(s):  
Cemal Özeroğlu ◽  
Sacide Erdoğan
Keyword(s):  
Molecular Weight ◽  
Thioglycolic Acid ◽  
Graphite Furnace ◽  
Oxidative Polymerization ◽  
Monomer Concentration ◽  
Water Soluble ◽  
Polymerization Reaction ◽  
Molar Ratio ◽  
Polymerization Time ◽  
Redox Systems

AbstractChemical polymerization of acrylamide at room temperature was examined by using thioglycolic acid-cerium (IV) sulfate and thioglycolic acid-KMnO4 redox systems in acid aqueous medium. Water soluble polyacrylamides containing thioglycolic acid end groups were synthesized. The effects of the molar ratio of acrylamide to Ce(IV) nAAm/nCe(IV), the polymerization time, the temperature, the monomer concentration, the molar ratio of cerium (IV) sulfate to thioglycolic acid and the concentration of sulfuric acid on the yield and molecular weight of polymer were investigated. Lower molar ratios of acrylamide/Ce(IV) at constant monomer concentration resulted in an increase in the yield but a decrease in molecular weight of polymer. The increase of reaction temperature from 20 to 70°C resulted in a decrease in the yield but generally resulted in a constant value for the molecular weight of polymer. With increasing polymerization time, the yield and molecular weight of polymer did not change substantially. Ce(IV) and Mn(VII) ions are reduced to Ce(III) and Mn(II) ions respectively in the polymerization reaction. The existence of Ce(III) ion bound to polymer was investigated by UV-visible spectrophotometry and fluoresce measurements. The amount of Mn(II) incorporated into the polymer was determined using graphite furnace atomic absorption spectrometry. The mechanism of this phenomenon is discussed.

Polymerization of n-butyl methylacrylate using bis(β- ketoamino)nickel(II)/MAO catalytic systems

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiaohui He ◽  
Yiwang Chen ◽  
Yongming Liu ◽  
Muqing Chen ◽  
Shuxian Yu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Monomer Concentration ◽  
Polymerization Temperature ◽  
Moderate Activity ◽  
Polymerization Time ◽  
Catalytic Systems ◽  
Molecular Weights ◽  
Molar Ratios ◽  
Broad Molecular Weight Distribution ◽  
C Nmr

AbstractThe polymerizations of n-butyl methylacrylate (nBMA) were carried out using bis(β-ketoamino)nickel(II) complexes (Ni[CH3C(O)CHC(NR)CH3]2: R = phenyl, 1; R = naphthyl, 2) in combination with methylaluminoxane (MAO) in toluene. The effect of parameters such as polymerization temperature, Al/Ni molar ratios, polymerization time, and monomer concentration, on catalytic polymerization activity and polymer molecular weights, were examined in detail. Both of the nickel(II) catalytic systems exhibited moderate activity, and produced P(nBMA) with high molecular weight and relatively broad molecular weight distribution (Mw/Mn=2.0~3.0. The obtained polymer has been characterized by means of FTIR, 1H NMR, 13C NMR, DSC, and WAXD technique and was confirmed to be syndio-rich stereospecific P(nBMA).

The Effects of Initiating Systems on CPAM Relative Molecular Weight and Strength Properties of Paperboard

2013 ◽  
Vol 821-822 ◽  
pp. 945-948
Author(s):  
Hui Rong Yang ◽  
Chuan Shan Zhao ◽  
Xue Zhang ◽  
Wen Jia Han
Keyword(s):  
Molecular Weight ◽  
Monomer Concentration ◽  
Strength Properties ◽  
Polymerization Temperature ◽  
Initiator Concentration ◽  
Redox Systems ◽  
Aqueous Polymerization ◽  
Relative Molecular Weight

initiator is one of the most important conditions of synthesizing efficient strength agent CPAM. To begin with initiating mechanism, three redox systems of acrylamide aqueous polymerization (NH4)2S2O8/ Na2SO3, K2S2O8/NaHSO3and K2S2O8/Na2S2O4have been studied. The effects of different kinds of initiator, initiator concentration, and monomer concentration as well as polymerization temperature on relative molecular weight and strength effects of CPAM have been investigated. K2S2O8/Na2SO3is the most useful system in synthesizing efficient strength agents.

scholarly journals Purification and Structural Characterization of a Novel Water-Soluble Neutral Polysaccharide from Cantharellus cibarius and Its Immunostimulating Activity in RAW264.7 Cells

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Long Chen ◽  
Xichun Peng ◽  
Jiaying Lv ◽  
Siyin Liao ◽  
Shiyi Ou ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Functional Food ◽  
Peritoneal Macrophages ◽  
Water Soluble ◽  
Raw264.7 Cells ◽  
Molar Ratio ◽  
Immunostimulating Activity ◽  
Ft Ir ◽  
Mouse Peritoneal Macrophages

Polysaccharide is one of the important active ingredients of Cantharellus cibarius. The aims of this work were to analyze preliminary characterization and to investigate immunostimulating activity of a novel water-soluble neutral polysaccharide named JP1, which was purified from the fruiting body of Cantharellus cibarius using DEAE-FF chromatography and Sephadex G-100 chromatography. The characteristics of JP1 were determined by HPGPC, FT-IR spectra, gas chromatography, and Congo Red Method. Immunostimulating activity of JP1 was investigated in RAW264.7 cells. Results indicated that JP1 consisted of L-Arabinose, D-Mannose, D-Glucose, and D-Galactose in a molar ratio of 1 : 1.06 : 1.95 : 1.17 with a molecular weight of 336 kDa. JP1 is nontoxic to RAW264.7 cells at this concentration range (62.5–1000 μg/mL). Furthermore, JP1 can promote mouse peritoneal macrophages to secrete NO and enhance the secretion of macrophages’ cytokines IL-6 in RAW264.7 cells. These results suggested that JP1 could have potential immunostimulating activity applications as medicine or functional food.

Synthesis of CdTe and CdTe/CdS Core-Shell Quantum Dots and their Optical Properties

2011 ◽  
Vol 306-307 ◽  
pp. 1350-1353 ◽  
Author(s):  
Juan Juan Lu ◽  
Shen Guang Ge ◽  
Fu Wei Wan ◽  
Jing Hua Yu
Keyword(s):  
Quantum Dots ◽  
Thioglycolic Acid ◽  
Water Soluble ◽  
Molar Ratio ◽  
Core Shell ◽  
The Core ◽  
Cdte Qds ◽  
Quality Water ◽  
Synthesis Procedure ◽  
Pl Emission

This paper describes the synthesis of CdTe and CdTe/CdS core-shell quantum dots (QDs) in aqueous solution. The quantum dots are prepared by using thioglycolic acid (TGA) as stabilizers. The synthesis procedure is simple and controllable. Different sized CdTe QDs with tuned PL wavelengths from 550 to 640 nm was synthesized by controlling reaction time within 5 h in aqueous solutions at a temperature of 100 °C. We also investigated the influence of precursor Cd/Te molar ratio for the prepared QDs. It was showed that the core-shell CdTe/CdS QDs have larger photoluminescence (PL) emission intensity than the original CdTe QDs. The synthesized core-shell CdTe/ZnS QDs have high quality, water-soluble and will be useful in applications of biolabeling, biosensing, and imaging.

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 The structure and subunit composition of the particulate NADH-ubiquinone reductase of bovine heart mitochondria

1976 ◽  
Vol 154 (2) ◽  
pp. 295-305 ◽  
Author(s):  
C. I Ragan
Keyword(s):  
Molecular Weight ◽  
Complex I ◽  
Gradient Centrifugation ◽  
Sodium Dodecyl ◽  
Water Soluble ◽  
Heart Mitochondria ◽  
Molar Ratio ◽  
Polypeptide Composition ◽  
Molecular Weights ◽  
Bovine Heart

Preparations of NADH-ubiquinone reductase from bovine heart mitochondria (Complex I) were shown to contain at least 16 polypeptides by gel electrophoresis in the presence of sodium dodecyl sulphate. 2. High-molecular-weight soluble NADH dehydrogenase prepared from Triton X-100 extracts of submitochondrial particles [Baugh & King (1972) Biochem. Biophys. Res. Commun. 49, 1165-1173] was similar to Complex I in its polypeptide composition. 3. Solubilization of Complex I by phospholipase A treatment and subsequent sucrose-density-gradient centrifugation did not alter the polypeptide composition. 4. Lysophosphatidylcholine treatment of Complex I caused some selective solubilization of a polypeptide of mol.wt. 33000 previosuly postulated to be the transmembrane component of Complex I in the mitochondrial membrane [Ragan (1975) in Energy Transducing Membranes: Structure, Function and Reconstitution (Bennun, Bacila & Najjar, eds.), Junk, The Hague, in the press]. 5. Chaotropic resolution of Complex I caused solubilization of polypeptides of molecular weights 75000, 53000, 29000, 26000 and 15500 and traces of others in the 10000-20000-mol.wt.range. 6. The major components of the iron-protein fraction from chaotropic resolution had molecular weights of 75000, 53000 and 29000, whereas the flavoprotein contained polypeptides of molecular weights 53000 and 26000 in a 1:1 molar ratio. 7. Iodination of Complex I by lactoperoxidase indicated that the water-soluble polypeptides released by chaotropic resolution, in particular those of the flavoprotein fraction, were largely buried in the intact Complex. 8. The polypeptides of molecular weights 75000, 53000, 42000, 39000, 33000, 29000 and 26000 were present in 1:2:1:1:1:1:1 molar proportions. The two subunits of molecular weight 53000 are probably non-identical.

Functional polyester fabric/polypyrrole polymer composites for electromagnetic shielding: Optimization of process parameters

2016 ◽  
Vol 47 (5) ◽  
pp. 686-711 ◽  
Author(s):  
Veronika Tunáková ◽  
Jan Grégr ◽  
Maroš Tunák ◽  
Gejza Dohnal
Keyword(s):  
Oxidative Polymerization ◽  
Monomer Concentration ◽  
Polyester Fabric ◽  
Textile Composites ◽  
Electromagnetic Shielding ◽  
Polymerization Temperature ◽  
Polymerization Time ◽  
Shielding Effectiveness ◽  
Textile Composite ◽  
Polyester Textile

Intrinsically conducting polymer polypyrrole/polyester textile composites were prepared by in situ chemical oxidative polymerization of polypyrrole on a polyester fabric. As an oxidizing agent ferric chloride was used, p-toluenesulfonic acid was used as a dopant. Polymerization conditions (concentration of monomer, polymerization time and temperature) were investigated and optimized by the help of Design of experiment methodology to obtain fabric with electromagnetic shielding efficiency at least 12 dB for frequency 1.5 GHz. Moreover, weight increase, macroscopic color shade of images and scanning electron microscopy images of samples were evaluated. It was found that all selected factors and their interactions have statistically significant effect on resulting electromagnetic shielding effectiveness, whereas monomer concentration has the highest positive influence. Experimental data were used to derive an empirical model linking the output and inputs. Optimized parameters (polymerization temperature 6.7℃, polymerization time 10 h and monomer concentration 5.8 g/l) for creating polypyrrole/polyester textile composite with electromagnetic shielding ability higher than 12 dB were successfully verified.

ANALISA KANDUNGAN BETA-GLUKAN LARUT AIR DAN LARUT ALKALI DARI TUBUH BUAH JAMUR TIRAM (Pleurotus ostreatus) DAN SHIITAKE (Lentinus edodes)

2013 ◽  
Vol 13 (3) ◽  
Author(s):  
Netty Widyastuti ◽  
Teguh Baruji ◽  
Henky Isnawan ◽  
Priyo Wahyudi ◽  
Donowati Donowati
Keyword(s):  
Molecular Structure ◽  
Molecular Weight ◽  
Immune System ◽  
Pleurotus Ostreatus ◽  
Water Soluble ◽  
Low Molecular Weight ◽  
Lentinus Edodes ◽  
Beta Glucan ◽  
Oyster Mushrooms ◽  
The Difference

Beta glucan is a polysaccharide compound, generally not soluble inwater and resistant to acid. Beta glucan is used as an immunomodulator (enhancing the immune system) in mammals is usually a beta-glucan soluble in water, easily absorbed and has a low molecular weight. Several example of beta-glucan such as cellulose (β-1 ,4-glucan), lentinan (β-1 0.6-glucan) and (β-1 ,3-glucan), pleuran (β-1, 6 and β-1 ,3-glucan) are isolated from species of fungi Basidiomycota include mushrooms (Pleurotus ostreatus) and shiitake (Lentinus edodes).The purpose of thisresearch activity is to obtain beta-glucan compound that can be dissolved in water and in alkali derived from fungi Basidiomycota, i.e, Oyster mushrooms (Pleurotus ostreatus) and shiitake (Lentinus edodes). The result of beta-glucan compared to characterize the resulting beta glucan that is molecular structure . The difference of beta glucan extraction is based on the differences in solubility of beta-glucan. Beta glucan could be water soluble and insoluble water.

Solubility Enhancement of the Poorly Water-Soluble Antiulcer Drug Famotidine by Inclusion Complexation

2013 ◽  
Vol 6 (1) ◽  
pp. 1983-1989 ◽  
Author(s):  
Shabnam Ain ◽  
V Gupta ◽  
Babita K ◽  
Q Ain ◽  
J Dahiya
Keyword(s):  
Inclusion Complex ◽  
Dissolution Rate ◽  
Phosphate Buffer ◽  
Physical Mixture ◽  
Water Soluble ◽  
Molar Ratio ◽  
Phase Solubility ◽  
Distilled Water ◽  
Physicochemical Interaction ◽  
Mixture Phase

Aqueous solubility is a critical factor for optimum drug delivery. In the present study, we investigated the potential of drug-cyclodextrin complexation as an approach for improving the solubility and bioavailability of famotidine, an H2-receptor antagonist and acid reducing drug which has poor solubility and bioavailability. Solubility improvement of drug by β-cyclodextrin was done by simple complexation approach using physical, kneading and co-precipitation methods and compared with physical mixture. Phase solubility profile indicated that the solubility of famotidine was significantly increased in presence of β-cyclodextrin and shows a linear graph with β-cyclodextrin indicating formation of inclusion complexes in a 1:1 molar ratio. β-Cyclodextrin-famotidine mixture have maximum stability constant 1477.6 M-1. The inclusion complex ratio 1:1 of kneading mixture was selected based on drug release profile and compared with physical mixture. Further characterization was done by  using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) to identify the physicochemical interaction between drug and carrier and its effect on dissolution. Dissolution rate studies for selected inclusion complex was performed in 0.1 N HCl (pH 1.2), phosphate buffer (pH 7.5) and distilled water (pH 6.8) and compared these to pure drug profile which was found to be 2.34 fold increase in distilled water, 1.83 fold in HCl and 2.01 fold in phosphate buffer (pH 7.5). These results suggest that the kneaded complex of famotidine with β-cyclodextrin as hydrophilic complexation agent can substantially enhance the solubility and dissolution rate. Such complex has promising potential to improve the bioavailability of famotidine.  

Metathesis Polymerization of Phenylacetylene by Tungsten Aryloxo Complexes

1995 ◽  
Vol 60 (3) ◽  
pp. 489-497 ◽  
Author(s):  
Hynek Balcar ◽  
Jan Sedláček ◽  
Marta Pacovská ◽  
Vratislav Blechta
Keyword(s):  
Molecular Weight ◽  
Catalytic Activity ◽  
Induction Period ◽  
Average Molecular Weight ◽  
Molar Fraction ◽  
Molar Ratio ◽  
Weight Average Molecular Weight ◽  
Polymer Yield ◽  
Positive Effect ◽  
Ligand Addition

Catalytic activity of the tungsten aryloxo complexes WCl5(OAr) and WOCl3(OAr), where Ar = 4-t-C4H9C6H4, 2,6-(t-C4H9)2C6H3, 2,6-Cl2C6H3, 2,4,6-Cl3C6H2, and 2,4,6-Br3C6H2 in polymerization of phenylacetylene (20 °C, monomer to catalyst molar ratio = 1 000) was studied. The activity of WCl5(OAr) as unicomponent catalysts increases with increasing electron withdrawing character of the -OAr ligand. Addition of two equivalents of organotin cocatalysts (Me4Sn, Bu4Sn, Ph4Sn, Bu3SnH) to WCl5(O-C6H2Cl3-2,4 ,6) has only slight positive effect (slightly higher polymer yield and/or molecular weight of poly(phenylacetylene)s was achieved). However, in the case of WOCl3(O-C6H3Cl2-2, 6) catalyst, it enhances the activity considerably by eliminating the induction period. Poly(phenylacetylene)s prepared with the catalysts studied have weight-average molecular weight ranging from 100 000 to 200 000. They are trans-prevailing and have relatively low molar fraction of monomer units comprised in cyclohexadiene sequences (about 6%).

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