Structural Studies of Native Paecilomyces sp. Exopolysaccharide

2007 ◽  
Vol 62 (9-10) ◽  
pp. 623-626
Author(s):  
Luis Lillo ◽  
Julio Alarcón ◽  
Gerardo Cabello ◽  
Sergio Águila
Keyword(s):  
Gel Permeation Chromatography ◽  
Structural Studies ◽  
H Nmr ◽  
Gel Permeation ◽  
C Nmr

A polysaccharide separated from Paecilomyces sp. was determined by gel permeation chromatography to be homogeneous. HPLC showed a monosaccharide containing d-glucose and d-fructose at a ratio of about 2:1. The results obtained from IR, 1H NMR, and 13C NMR analyses confirmed the proposed structure.

Silicon alkyne hybrid polymers containing Si–H and Si–CH3

2017 ◽  
Vol 30 (3) ◽  
pp. 259-266 ◽  
Author(s):  
Shuaishuai Liu ◽  
Quan Zhou ◽  
Zhengqiang Peng ◽  
Ning Song ◽  
Lizhong Ni
Keyword(s):  
Oxidative Stability ◽  
Oxidation Resistance ◽  
Gel Permeation Chromatography ◽  
High Heat ◽  
Structure Design ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Thermal And Oxidative Stability ◽  
Gel Permeation ◽  
C Nmr

A silicon-containing polymer (HMSA), synthesized with n-BuLi, trichloroethylene, dichloromethylsilane, and dimethyldichlorosilane, with three different proportions of Si–H, and its influence on thermal oxidation have been studied. The structures of HMSA were characterized by Fourier transform infrared spectra, 1H-Nuclear Magnetic Resonance (H-NMR), 13C-NMR, 29Si-NMR, and gel permeation chromatography. Thermal and oxidative stabilities were studied by differential scanning calorimetry and thermogravimetric analysis, and the cross-linking reaction mechanisms of the HMSA were discussed. All the polymers exhibited excellent thermal and oxidation resistance; particularly, HMSA-1 showed high heat-resistant and thermo-oxidative stability; the temperatures of 5% weight loss ( Td5) were 636.3 and 645.5°C, and the residues at 1000°C were 87.07 and 86.23% in nitrogen and air, respectively. This system had excellent thermal and oxidative stability, and through the structure design, control of heat oxidation resistance was realized.

Synthesis and characterization of 4-chloromethylstyrene polymers containing bulky organosilicon groups

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Kazem Dindar Safa ◽  
Mirzaagha Babazadeh
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Gel Permeation Chromatography ◽  
Synthesis And Characterization ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Gel Permeation ◽  
Covalently Linked ◽  
C Nmr

Abstract The homopolymer of 4-chloromethylstyrene and its copolymers with styrene (in 1:3 and 1:1 mole ratio) were synthesized by bulk and solution freeradical polymerisations, respectively, at 70±1°C using α,α'-azoisobutyronitrile as an initiator. Highly sterically hindered tris(trimethylsilyl)methyl (Tsi) substituents were then covalently linked to the obtained homopolymer and copolymers. The polymers were characterized by IR, 1H NMR and 13C NMR, differential scanning calorimetry (DSC) and gel permeation chromatography. DSC showed that incorporation of Tsi substituents in the side chains of homopolymer and copolymers increases the rigidity of the polymers and, subsequently, their glass transition temperature.

Structural studies of oligosilanes produced by catalytic dehydrogenative coupling of primary organosilanes

1987 ◽  
Vol 65 (8) ◽  
pp. 1804-1809 ◽  
Author(s):  
C. Aitken ◽  
J. F. Harrod ◽  
U. S. Gill
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Gel Permeation Chromatography ◽  
Structural Studies ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Dehydrogenative Coupling ◽  
Weight Distributions ◽  
Gel Permeation ◽  
End Groups

The structures of some poly(organosilylenes), [Formula: see text] (R = Ph, p-tolyl, n-hexyl, and benzyl), produced by catalytic dehydrogenative coupling of primary silanes have been studied by infrared, nuclear magnetic resonance, and mass spectroscopies. These results, combined with data on molecular weights and molecular weight distributions from vapour pressure osmometry and gel permeation chromatography, lead to the conclusion that the polymers are linear and have SiH2R end groups. The polymers all have degrees of polymerization of ca. 10 and very narrow molecular weight dipersions. Some possible features of the mechanism that gives rise to this behaviour are discussed.

Cationic copolymerization of 1,3-pentadiene with α-pinene

2014 ◽  
Vol 34 (7) ◽  
pp. 583-589 ◽  
Author(s):  
Ai-Yuan Li ◽  
Xiang-Dong Sun ◽  
Hui-Bo Zhang ◽  
Yong-Chun Zhang ◽  
Bin Wang ◽  
...  
Keyword(s):  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Polymerization Temperature ◽  
Scanning Calorimetry ◽  
Gardner Color ◽  
H Nmr ◽  
Cationic Copolymerization ◽  
Ft Ir ◽  
Better Than ◽  
C Nmr

Abstract The cationic copolymerization of 1,3-pentadiene (PD) with α-pinene (AP) initiated by aluminum trichloride (AlCl3) was carried out in N-pentane solvent. The effects of the polymerization temperature and the comonomer composition on the yield of the copolymer, softening point, Gardner color scale and number-average molecular weight (Mn) are discussed. The performance of the copolymer was better than that of AP homopolymer (PAP) and PD homopolymer (PPD). The structure of the copolymer was characterized by Fourier transform infrared spectroscopy (FT-IR), 1H-nuclear magnetic resonance (1H-NMR), 13C-NMR, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC). In addition, the reactivity ratios for AP (M1) and PD (M2) determined by the Kelen-Tudos method from low-conversion data are r1=0.58 and r2=5.92, respectively.

scholarly journals Antimicrobial Applications of Transition Metal Complexes of Benzothiazole Based Terpolymer: Synthesis, Characterization, and Effect on Bacterial and Fungal Strains

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Mohamed A. Riswan Ahamed ◽  
Raja S. Azarudeen ◽  
N. Mujafar Kani
Keyword(s):  
Metal Complexes ◽  
Elemental Analysis ◽  
Biological Activities ◽  
Gel Permeation Chromatography ◽  
Spectral Studies ◽  
X Ray Diffraction ◽  
Spectral Techniques ◽  
H Nmr ◽  
Uv Visible ◽  
C Nmr

Terpolymer of 2-amino-6-nitro-benzothiazole-ethylenediamine-formaldehyde (BEF) has been synthesized and characterized by elemental analysis and various spectral techniques like FTIR, UV-Visible, and1H and13C-NMR. The terpolymer metal complexes were prepared with Cu2+, Ni2+, and Zn2+metal ions using BEF terpolymer as a ligand. The complexes have been characterized by elemental analysis and IR, UV-Visible, ESR,1H-NMR, and13C-NMR spectral studies. Gel permeation chromatography was used to determine the molecular weight of the ligand. The surface features and crystalline behavior of the ligand and its complexes were analyzed by scanning electron microscope and X-ray diffraction methods. Thermogravimetric analysis was used to analyze the thermal stability of the ligand and its metal complexes. Kinetic parameters such as activation energy(Ea)and order of reaction (n) and thermodynamic parameters, namely,ΔS,ΔF,S*, andZ, were calculated using Freeman-Carroll (FC), Sharp-Wentworth (SW), and Phadnis-Deshpande (PD) methods. Thermal degradation model of the terpolymer and its metal complexes was also proposed using PD method. Biological activities of the ligand and its complexes were tested againstShigella sonnei,Escherichia coli,Klebsiellaspecies,Staphylococcus aureus,Bacillus subtilis, andSalmonella typhimuriumbacteria andAspergillus flavus,Aspergillus niger,Penicilliumspecies,Candida albicans,Cryptococcus neoformans,Mucor speciesfungi.

A facile method to prepare methylcellulose from annual plants and wood using iodomethane

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Daiyong Ye ◽  
Xavier Farriol
Keyword(s):  
Hydrogen Peroxide ◽  
Ambient Temperature ◽  
Dimethyl Sulfoxide ◽  
Gel Permeation Chromatography ◽  
Annual Plants ◽  
Molecular Weights ◽  
Gel Permeation ◽  
Key Factor ◽  
Naoh Solution ◽  
C Nmr

AbstractA novel facile method was developed to prepare methylcellulose from miscanthus, cardoon and eucalyptus. Pulps were obtained by the impregnation rapid steam pulping process (IRSP). A total-chlorine-free (TCF) method was used to bleach the pulps with hydrogen peroxide. Bleached pulps were mercerized in 40% NaOH solution for one hour at ambient temperature. Mercerized cellulose reacted with iodomethane in 2-propanol slurry at 60°C for 22 h. Mercerization and methylation were repeated. Intrinsic viscosities of methylcellulose were measured in 4% NaOH solution. Super-molecular substitution patterns of methylcellulose were determined by 13C NMR. Molecular weights of methylcellulose were measured in dimethyl sulfoxide by gel permeation chromatography. Pulping severity is a key factor influencing the properties of the methylcellulose prepared.

Bioconjugation of papain with poly(N-vinylpyrrolidone): NMR characterization and study of its enzymatic activity

2021 ◽  
Vol 99 (1) ◽  
pp. 10-17
Author(s):  
L.E. Verduzco ◽  
Ana L. García-Pérez ◽  
Ramiro Guerrero-Santos ◽  
Antonio Ledezma-Pérez ◽  
Jorge Romero-García ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Catalytic Activity ◽  
Chain Transfer ◽  
Gel Permeation Chromatography ◽  
Acid Group ◽  
H Nmr ◽  
Reversible Addition ◽  
Nmr Characterization ◽  
Vis Spectroscopy ◽  
C Nmr

A poly(vinylpyrrolidone) end-functionalized with a carboxylic acid group (PVP–CO2H) was synthesized by reversible addition-fragmentation chain transfer (RAFT)/macromolecular design via the interchange of xanthates (MADIX) polymerization mediated by 4-(O-ethylxanthyl)methyl benzoic acid. The molecular weight of the as-synthesized PVP–CO2H was estimated through UV–vis spectroscopy (Mn(UV–vis) = 7322 g/mol), gel permeation chromatography (GPC) (Mn(GPC) = 8670 g/mol), and 1H NMR, (Mn(NMR) = 8207 g/mol). The values obtained were close with the theoretical molecular weight (Mn(th) = 7925 g/mol). Subsequently, the preformed PVP–CO2H was activated to produce N-succinimidyl poly(vinylpyrrolidone) (PVP–NHS). This precursor was covalently coupled to papain to produce bioconjugate PVP–papain. The functional group modifications in the PVP chain-end were observed by the variations in the chemical shift values by 1H and 13C NMR and FTIR analysis at each step of the synthesis. The molecular weight of the PVP–papain was obtained by SEC–HPLC and suggests that, on average, four or five chains of PVP–CO2H were attached to one papain molecule. Compared with papain, the PVP–papain exhibited significantly improved catalytic activity, pH, and thermal stability. Additionally, the storage studies showed that the catalytic activity of PVP–papain was about 79% versus the native enzyme (29%), and this activity was maintained even when it was stored for 25 days.

scholarly journals 1-n-Butyl-3-methylimidazolium-2-carboxylate: a versatile precatalyst for the ring-opening polymerization of ε-caprolactone and rac-lactide under solvent-free conditions

2013 ◽  
Vol 9 ◽  
pp. 647-654 ◽  
Author(s):  
Astrid Hoppe ◽  
Faten Sadaka ◽  
Claire-Hélène Brachais ◽  
Gilles Boni ◽  
Jean-Pierre Couvercelle ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Ring Opening ◽  
Gel Permeation Chromatography ◽  
Ring Opening Polymerization ◽  
Solvent Free ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Solvent Free Conditions ◽  
Gel Permeation

The ring-opening polymerization of ε-caprolactone (ε-CL) and rac-lactide (rac-LA) under solvent-free conditions and using 1-n-butyl-3-methylimidazolium-2-carboxylate (BMIM-2-CO2) as precatalyst is described. Linear and star-branched polyesters were synthesized by successive use of benzyl alcohol, ethylene glycol, glycerol and pentaerythritol as initiator alcohols, and the products were fully characterized by 1H and 13C{1H} NMR spectroscopy, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). BMIM-2-CO2 acts as an N-heterocyclic carbene precursor, resulting from in situ decarboxylation, either by heating under vacuo (method A) or by addition of NaBPh4 (method B). Possible catalytic and deactivation mechanisms are proposed.

Synthesis of novel single site tin porphyrin complexes and the catalytic activity of tin tetrakis(4-fluorophenyl)porphyrin over 𝜀-caprolactone

2017 ◽  
Vol 21 (03) ◽  
pp. 231-237 ◽  
Author(s):  
Hanifi Yaman ◽  
Asgar Kayan
Keyword(s):  
Catalytic Activity ◽  
Mass Spectroscopy ◽  
Elemental Analysis ◽  
Gel Permeation Chromatography ◽  
Single Site ◽  
Gel Permeation ◽  
Tin Porphyrin ◽  
C Nmr

Tin tetrakis(4-fluorophenyl)porphyrin, tin tetrakis(4-chlorophenyl)porphyrin and tin tetrakis(4-bromophenyl)porphyrin complexes were prepared by reaction of butyltin trichloride with tetrakis(4-fluorophenyl)porphyrin, tetrakis(4-chlorophenyl)porphyrin, and tetrakis(4-bromophenyl)porphyrin in tetrahydrofuran and toluene, respectively. These novel complexes were characterized by [Formula: see text]H, [Formula: see text]C NMR, FTIR, mass spectroscopy and elemental analysis. The single site tin complex including fluoride was tested as a catalyst in polymerization of [Formula: see text]-caprolactone and was very effective. Polycaprolactone was characterized by [Formula: see text]H, [Formula: see text]C NMR, and gel permeation chromatography.

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