scholarly journals Hyperbranched Polycarbosiloxanes: Synthesis by Piers-Rubinsztajn Reaction and Application as Precursors to Magnetoceramics

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 672 ◽  
Author(s):  
Huayu Zhang ◽  
Lei Xue ◽  
Jianquan Li ◽  
Qingyu Ma
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Elevated Temperature ◽  
Room Temperature ◽  
Gel Permeation Chromatography ◽  
29Si Nmr ◽  
Molecular Weights ◽  
Gel Permeation ◽  
Functional Ceramics ◽  
29Si Nmr Spectroscopy

Silicon-containing hyperbranched polymers (Si-HBPs) have drawn much attention due to their promising applications. However, the construction of Si-HBPs, especially those containing functional aromatic units in the branched backbones by the simple and efficient Piers-Rubinsztajn (P–R) reaction, has been rarely developed. Herein, a series of novel hyperbranched polycarbosiloxanes were prepared by the P–R reactions of methyl-, or phenyl-triethoxylsilane and three Si–H containing aromatic monomers, including 1,4-bis(dimethylsilyl)benzene, 4,4′-bis(dimethylsilyl)-1,1′-biphenyl and 1,1′-bis(dimethylsilyl)ferrocene, using B(C6F5)3 as the catalyst for 0.5 h at room temperature. Their structures were fully characterized by Fourier transform infrared spectroscopy, 1H NMR, 13C NMR, and 29Si NMR. The molecular weights were determined by gel permeation chromatography. The degrees of branching of these polymers were 0.69–0.89, which were calculated based on the quantitative 29Si NMR spectroscopy. For applications, the ferrocene-linked Si-HBP can be used as precursors to produce functional ceramics with good magnetizability after pyrolysis at elevated temperature.

Characterization of LARCTM-CPI 2 poly(amide acid) aging by gel permeation chromatography/differential viscometry

1995 ◽  
Vol 7 (1) ◽  
pp. 55-68 ◽  
Author(s):  
E J Siochi ◽  
S J Havens ◽  
P R Young ◽  
P M Hergenrother
Keyword(s):  
Molecular Weight ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Gel Permeation Chromatography ◽  
Concentrated Solutions ◽  
Solution Property ◽  
Molecular Weights ◽  
Gel Permeation ◽  
Property Changes

A controlled-molecular-weight LARCr'-CPI 2 poly(amide acid) was synthesized to investigate solution property changes that result from aging'Both dilute and concentrated solutions were aged at five temperatures and periodically analysed over a 33 d period. Various molecular weight parameters were obtained by gel permeation chromatography in combination with differential viscometry. Chemical changes were also followed by Fourier transform infrared spectroscopy. The temperatures used allowed the calculation of the energy of activation associated with changes in weight and number average molecular weights.

Study on Structure and Tanning Properties of Copolymer of Resorcinol and 3,5-Dihydroxyl Benzoic Acid

2012 ◽  
Vol 487 ◽  
pp. 48-52
Author(s):  
Sheng Hua Lv ◽  
Gong Rui ◽  
Di Li
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Gel Permeation Chromatography ◽  
Radical Copolymerization ◽  
Mass Ratio ◽  
Monomer Composition ◽  
Chrome Tanning ◽  
Gel Permeation

The radical copolymerization of resorcinol (RSC) and 3,5-dihydroxyl benzoic (DHBA) was carried out in water by the initiator of horseradish (HRP)/H2O2. It was discussed that the effects of monomer composition on the properties of the copolymer. The best monomer mass ratio of RSC:DHBA was 60:40 and the shrink temperature can reached to 88.5oC. The tanning result indicated that the copolymer of RSC and DHPA has particularly excellent tanning properties and can be served as leather tannage substitute for chrome tanning materials. And also the mechanism of the HRP initiated copolymerization was proposed. The structure and molecular weight of the copolymer was characterized by Fourier Transform Infrared spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR) and Gel Permeation Chromatography (GPC). The copolymer can be as tannage and retannage in making leather process. The results showed that it has excellent tanning properties and retanning effects.

Study on Synthesis and Properties of Phenols Polymer Syntan Catalyzed by Enzyme

2011 ◽  
Vol 138-139 ◽  
pp. 1072-1077
Author(s):  
Sheng Hua Lv ◽  
Rui Gong ◽  
Yan Fen Ma
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Molar Ratio ◽  
Structure And Properties ◽  
Monomer Composition ◽  
Gel Permeation

A phenolic copolymer was synthesized from resorcinol (RSC) and 3,5-dihydroxy benzoic acid (DBA) using horseradish peroxidase (HRP)/H2O2 as the radical copolymerization’s initiateor. It was discussed that the effects of monomer composition on the properties of the copolymer. The best molar ratio was 1:1. The structure and properties of the copolymer was characterized by Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (HNMR), Molecular weight (MW) was determined by gel permeation chromatography (GPC). The result shows that the average molecular weight of the copolymer is about 40000. The effect of dosage of HRP on the properties of the copolymer was investigated. And the mechanism of polymerization of RSC and DBA was advanced. The copolymer was used as tanning agent, applied results show that it has excellent retanning properties. It was realized the applicatiom of HRP on the phenols syntan.

Degradation of ABS in ABS/CaCO3 Composites during Reprocessing

2012 ◽  
Vol 455-456 ◽  
pp. 845-850 ◽  
Author(s):  
Xiao Juan Bai ◽  
Zhe Wu ◽  
Nan Feng
Keyword(s):  
Mechanical Properties ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Impact Strength ◽  
Acrylonitrile Butadiene Styrene ◽  
Gel Permeation Chromatography ◽  
Gel Permeation ◽  
Rubber Phase ◽  
The Impact ◽  
Butadiene Styrene

Acrylonitrile-Butadiene-Styrene (ABS)/CaCO3 composites were reprocessed under normal conditions. The effects of reprocessing on the degradation of ABS were investigated by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). The mechanical properties of the reprocessed materials were measured. In this paper, a method to evaluate the degradation of ABS in ABS/CaCO3 composites by FTIR was described. The results show that within the range of the reprocessing cycles studied, as the number of reprocessing cycles increased, the impact strength of composite was significantly reduced if the content of CaCO3 is lower than 10%, due to the degradation of rubber phase. However, the impact strength was almost unchanged when the content of CaCO3 was higher than 15%.

scholarly journals Efficient determination and pesticide control by means of immobilization of acetylcholinesterase

2017 ◽  
Vol 36 (1) ◽  
Author(s):  
Elvan Hasanoğlu Özkan ◽  
Nurdan Kurnaz Yetim ◽  
Murat Gümüş ◽  
Nurşen Sarı ◽  
Ali Dişli
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Gel Permeation Chromatography ◽  
Condensation Method ◽  
Gel Permeation ◽  
Tetrazole Derivatives ◽  
Scanning Electron

Supports involving tetrazole (o/m/p-F-Tet-1H) were prepared to detect pesticides. This novel te-trazole including fluorine in different positions was attached to nanoparticles (2AEPS-(o/m/p-F-Tet-1H)) by a condensation method. Primarily, the tetrazole derivatives were characterized by 1H-NMR,13C-NMR and LC-MS. Then, nanoparticles were prepared by a condensation method in non-aqueous medium and characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, gel permeation chromatography. The enzymatic properties of immobilized acetylcholinesterase (AChE) were investigated for the determination of phosmet. This research is the first example.

scholarly journals Purification and characterization of two human erythrocyte arylamidases preferentially hydrolysing N-terminal arginine or lysine residues

1978 ◽  
Vol 175 (3) ◽  
pp. 1051-1067 ◽  
Author(s):  
K K Mäkinen ◽  
P L Mäkinen
Keyword(s):  
Substrate Inhibition ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Gel Permeation Chromatography ◽  
Ph Optimum ◽  
Preparative Scale ◽  
Molecular Weights ◽  
Gel Permeation ◽  
Lysine Residues ◽  
Enzyme I

Two arylamidases (I and II) were purified from human erythrocytes by a procedure that comprised removal of haemoglobin from disrupted cells with CM-Sephadex D-50, followed by treatment of the haemoglobin-free preparation subsequently with DEAE-cellulose, gel-permeation chromatography on Sephadex G-200, gradient solubilization on Celite, isoelectric focusing in a pH gradient from 4 to 6, gel-permeation chromatography on Sephadex G-100 (superfine), and finally affinity chromatography on Sepharose 4B covalently coupled to L-arginine. In preparative-scale purifications, enzymes I and II were separated at the second gel-permeation chromatography. Enzyme II was obtained as a homogeneous protein, as shown by several criteria. Enzyme I hydrolysed, with decreasing rates, the L-amino acid 2-naphtylamides of lysine, arginine, alanine, methionine, phenylalanine and leucine, and the reactions were slightly inhibited by 0.2 M-NaCl. Enzyme II hydrolysed most rapidly the corresponding derivatives of arginine, leucine, valine, methionine, proline and alanine, in that order, and the hydrolyses were strongly dependent on Cl-. The hydrolysis of these substrates proceeded rapidly at physiological Cl- concentration (0.15 M). The molecular weights (by gel filtration) of enzymes I and II were 85 000 and 52 500 respectively. The pH optimum was approx. 7.2 for both enzymes. The isoelectric point of enzyme II was approx. 4.8. Enzyme I was activated by Co2+, which did not affect enzyme II to any noticeable extent. The kinetics of reactions catalysed by enzyme I were characterized by strong substrate inhibition, but enzyme II was not inhibited by high substrate concentrations. The Cl- activated enzyme II also showed endopeptidase activity in hydrolysing bradykinin.

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