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.

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.

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.

Synthesis and characterization of novel organosoluble aromatic copolyimides

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Jintian Yang ◽  
Wei Huang ◽  
Yongfeng Zhou ◽  
Deyue Yan ◽  
Xiaohang Wang
Keyword(s):  
Gel Permeation Chromatography ◽  
Polymer Chains ◽  
Polymerization Process ◽  
Synthesis And Characterization ◽  
Aprotic Solvents ◽  
Solution Casting ◽  
Molecular Weights ◽  
Gel Permeation ◽  
Dipolar Aprotic Solvents

AbstractA series of novel aromatic copolyimides was synthesized from pyromellitic dianhydride with the commercial diamine 4,4’-methylenebisaniline (MBA) and the diamine 4,4’-methylenebis(2-tert-butylaniline) (MBTBA) specially designed by ourselves. The solubility of the copolyimides in conventional solvents decreased with the mole ratio of MBTBA to MBA. When MBTBA/MBA was larger than 8/2, the copolyimides are soluble in low boiling point solvents (such as chloroform and tetrahydrofuran) and can form a transparent, flexible, tough film by solution casting. When MBTBA/MBA was between 7/3 and 5/5, the copolyimides are only soluble in dipolar aprotic solvents (such as dimethylformamide and N-methyl-2-pyrrolidone) and form films, too. The copolyimide was precipitated in m-cresol in the polymerization process when MBTBA/MBA was lower than 5/5. The number-average molecular weights of the soluble copolyimides measured by gel permeation chromatography were larger than 5.0·104 and the polydispersity index was higher than 1.5. Only one glass transition of these copolyimides was detected at around 350°C. The copolyimides did not show appreciable decomposition up to 400°C under air and 550°C under nitrogen, and their thermal stability increased a little with the introduction of MBA into the polymer chains.

scholarly journals Chromatographic characterization of products isolated from chrome shavings

1999 ◽  
Vol 42 (3) ◽  
pp. 281-290
Author(s):  
Edivaldo E Garcia ◽  
Cláudia C.M Kimura ◽  
Ariovaldo C Martins ◽  
Gisele O Rocha ◽  
Jorge Nozaki
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
High Performance Liquid Chromatography ◽  
High Performance ◽  
Chemical Characterization ◽  
Gel Permeation Chromatography ◽  
Gel Permeation ◽  
Chromatographic Characterization ◽  
Free Aminoacids

Gel permeation chromatography and high performance liquid chromatography were employed for separation and chemical characterization of products isolated from chrome shavings. After enzymatic hydrolysis, the products isolated were peptides of higher molecular weight. Peptides of lower molecular weight and free aminoacids were the main products using sulfuric acid in chrome shavings solubilization. Glycine (17%) , glutamic acid (10.6%) , alanine (9.2%) , and arginine (8.2%) were the principal amino acids found. Phenylalanine(1.8%) was the main aromatic amino acid , while tryptophane was completely absent.

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