Polymerization of Methyl Methacrylate with a Novel Titanium Complex

2011 ◽  
Vol 179-180 ◽  
pp. 1203-1207
Author(s):  
Zheng Zai Cheng ◽  
Yu Jing Nie ◽  
Xiao Chao Yan ◽  
Rui Lei ◽  
Su Su Lin
Keyword(s):  
Molecular Weight ◽  
Methyl Methacrylate ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Ligand Complex ◽  
Dichloromethane Solution ◽  
Titanium Complex ◽  
Methyl Methacrylate Polymerization ◽  
Gel Permeation ◽  
Very High

Novel titanium complex [2-O-(5- NO2)C6H3CH=N[(C6H4) –2-O ]]2TiCl2 (1) has been prepared by treatment of the ligand complex 1a with TiCl4•2THF in dichloromethane solution. The complex 1a and 1 were characterized by 1H-NMR . Activated by MAO, Complex 1 displayed very high activity for methyl methacrylate polymerization and the viscosity-average molecular weight of PMMA is more than 35×104 at 60°C.The molecular-weight distribution of PMMA measured by gel permeation chromatography (GPC) is narrow.

Ethylene Polymerization by a New Zirconium Complex

2011 ◽  
Vol 214 ◽  
pp. 699-703
Author(s):  
Zheng Zai Cheng ◽  
Yu Jing Nie ◽  
Xiao Chao Yan ◽  
Rui Lei ◽  
Su Su Lin
Keyword(s):  
Molecular Weight ◽  
Reaction Temperature ◽  
Ethylene Polymerization ◽  
Average Molecular Weight ◽  
Zirconium Complex ◽  
Melting Points ◽  
Ligand Complex ◽  
Dichloromethane Solution ◽  
Gel Permeation ◽  
Very High

Novel zirconium complex C2 has been prepared by treatment of the ligand complex C1 with ZrCl4•2THF in dichloromethane solution. The complex C1 and C2 were characterized by 1H-NMR and IR. Activated by MAO, Complex C2 displays very high activity for ethylene polymerization under the reaction temperature of 30～80°C and the viscosity-average molecular weight of polyethylene is more than 3.50×104 when reaction temperature is no more than 60°C.The molecular-weight distribution measured by gel permeation reached 2.3.High melting points measured by DSC indicates that the polyethylene produced by complex C2 is high linearity and high crystallinity.

Prepare of Novel Zirconium Complex and Catalytic Performance for Ethylene Polymerization

2011 ◽  
Vol 179-180 ◽  
pp. 1091-1095 ◽  
Author(s):  
Zheng Zai Cheng ◽  
Yu Jing Nie ◽  
Xiao Chao Yan ◽  
Rui Lei ◽  
Su Su Lin
Keyword(s):  
Molecular Weight ◽  
Reaction Temperature ◽  
Ethylene Polymerization ◽  
Average Molecular Weight ◽  
Catalytic Performance ◽  
Zirconium Complex ◽  
Melting Points ◽  
Ligand Complex ◽  
Dichloromethane Solution ◽  
Very High

Novel zirconium complex 2 has been prepared by treatment of the ligand complex 1 with ZrCl4•2THF in dichloromethane solution. The complex 1 and 2 were characterized by 1H-NMR and IR. Activated by MAO, Complex 2 displays very high activity for ethylene polymerization under the reaction temperature of 40～80 °C and the viscosity-average molecular weight of polyethylene is more than 3.0×104 when reaction temperature is no more than 60°C.The molecular-weight distribution measured by gel permeation reached 2.50.High melting points measured by DSC indicates that the polyethylene produced by complex 2 is high linearity and high crystallinity.

Randomly Branched Polymers. II. Computer Analysis of Gel-Permeation Chromatograms

1976 ◽  
Vol 49 (5) ◽  
pp. 1290-1304
Author(s):  
M. Kurata ◽  
H. Okamoto ◽  
M. Iwama ◽  
M. Abe ◽  
T. Homma
Keyword(s):  
Molecular Weight ◽  
Weight Distribution ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Computer Method ◽  
Branched Polymers ◽  
Branch Points ◽  
Weight Average Molecular Weight ◽  
Degree Of Branching ◽  
Gel Permeation

Abstract An iterative computer method was proposed for estimating the degree of branching and molecular weight distribution simultaneously from a pair of measurements on intrinsic viscosity and gel-permeation chromatography. The validity of the method as applied to randomly branched polymers was tested by using both fractionated and unfractionated samples of branched polystyrenes. It was experimentally concluded that the average number of branch points per unit molecular weight, λ, can be determined by this method with an accuracy of about 15%, and the weight-average molecular weight with accuracy of about 10%.

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.

Article

1998 ◽  
Vol 76 (11) ◽  
pp. 1699-1706 ◽  
Author(s):  
Jonathan Z Knaul ◽  
Mohammad R Kasaai ◽  
V Tam Bui ◽  
Katherine AM Creber
Keyword(s):  
Molecular Weight ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Solvent System ◽  
Similar Degree ◽  
Degree Of Deacetylation ◽  
Molecular Weights ◽  
Good Accord ◽  
Gel Permeation ◽  
Weight Analysis

Starting from a chitosan sample with a degree of deacetylation of 71%, three separate sample sets were generated by successive deacetylation and reacetylation processes. The degree of deacetylation of samples was determined by UV spectrometry supported by thermogravimetric analysis. The molecular weight of chitosan samples was determined in a solvent system of 0.25 M CH3COOH/0.25 M CH3COONa, using viscometry and gel permeation chromatography (GPC) with a TSK-gel column. The first set of samples had a similar degree of deacetylation (DDA) but differing molecular weights. The second set of samples had a similar molecular weight but differing degrees of deacetylation. The Mark-Houwink-Sakurada constants used for the determination of viscosity average molecular weight and the universal calibration of the GPC system were K = 1.40 × 10-4 dL/g and a = 0.83. Results showed that molecular weights determined from both techniques are in good accord only at lower degrees of deacetylation. This may be attributed to the fact that the chemical structure of chitosan samples could have been largely altered with increasing or decreasing degree of deacetylation. Nevertheless, the trend with which the molecular weights vary with the deacetylation time is consistent over a limited DDA range. A literature review of molecular weight analysis of chitosan is included.Key words: chitosan, degree of deacetylation, gel permeation chromatography, molecular weight, viscometry.

Study on Preparation and Properties of Copolymer of Phenol and Acrylamide by Enzyme Catalyzed Polymerization

2010 ◽  
Vol 129-131 ◽  
pp. 872-876
Author(s):  
Yan Fen Ma ◽  
Sheng Hua Lv ◽  
Gang Liu ◽  
Jian Ping Duan ◽  
Rui Jun Gao
Keyword(s):  
Molecular Weight ◽  
Fourier Transform ◽  
Horseradish Peroxidase ◽  
Ftir Spectroscopy ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Fourier Transform Infrared ◽  
Monomer Composition ◽  
Gel Permeation ◽  
Distribution Index

The copolymer of phenol and acrylamide was synthesized by copolymerization using horseradish peroxidase (HRP)/H2O2 as catalyst. The effect of monomer composition on the copolymer tanning agent properties was investigated. The structure of the copolymer was characterized by Fourier transform infrared (FTIR) spectroscopy. The molecular weight was determined by gel permeation chromatography (GPC). The result shows that the average molecular weight of the copolymer is about 1900. Its molecule distribution index is much narrower. The copolymer was used as tanning agent, the result shows that the applied leather is excellent in softness and dyeing.

scholarly journals Effect of Various Temperatures on Bletillae Rhizoma Polysaccharide Extraction and Physicochemical Properties

2018 ◽  
Vol 9 (1) ◽  
pp. 116 ◽  
Author(s):  
Xiaoyan Long ◽  
Quan Yan ◽  
Linwei Peng ◽  
Xinyue Liu ◽  
Xuegang Luo
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Extraction Temperature ◽  
X Ray Diffraction ◽  
Simple Process ◽  
X Ray ◽  
Gel Permeation ◽  
Scanning Electron

Six fractional polysaccharides were prepared by water extraction and alcohol precipitation under controlled temperature from bletillae rhizoma, a traditional Chinese medicine. Based on this, yields of bletillae rhizome polysaccharides (RBPs) were obtained. The extracting temperature impacted the characteristics of the fractional polysaccharides. The fractional polysaccharides were characterized by glucomannan (GM) content, thermal stability, scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, gel permeation chromatography (GPC), and x-ray diffraction (XRD). For the analysis, 2.0% w/v dispersions of the six fractional polysaccharides were prepared and their flow behaviors were evaluated using a rotational rheometer. The results showed that increased extraction temperature led to increased GM extraction yields and extraction rate, but GM content was relative stable (over 90%). The average molecular weight (Mw) of fractional polysaccharides obtained at 30, 40, 50, 60, 70, and 80 °C was 3.598 × 104, 4.188 × 104, 8.632 × 104, 8.850 × 104, 2.372 × 105, and 3.081 × 105 g/mol, respectively. SEM revealed that fractional polysaccharides had a porous structure of different sizes and densities. Thermal analysis, FTIR, and XRD results indicated that extraction temperature affects the structure and moisture content of fractional polysaccharides. All results showed that the extraction temperature has an obvious impact on the morphology, molecular weight, and polydispersity of the RBPs. This simple process is a promising method for the preparation of fractional polysaccharides.

Research on Aging Mechanism of Modified Asphalt by Gel Permeation Chromatography and Grey Relevant Methods

2011 ◽  
Vol 230-232 ◽  
pp. 1005-1009
Author(s):  
Yan Zhou ◽  
Kai Zhang ◽  
Shuan Fa Chen
Keyword(s):  
Molecular Weight ◽  
Elastic Recovery ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Modified Asphalt ◽  
Aging Mechanism ◽  
Dispersion Degree ◽  
Gel Permeation ◽  
Macroscopic Properties ◽  
Before And After

The aging of modified asphalt includes modifier and asphalt aging. Combining with the changes of macroscopic properties index for modified asphalt before and after aging, aging mechanism of modified asphalt was studied by gel permeation chromatography(GPC) and grey relevant methods. And the results indicated that changes in content, molecular weight and dispersion degree of asphalt before and after aging are the most significant factors influencing macroscopic properties of modified asphalt. Asphalt content is the most significant factor influencing penetration, toughness and tenacity, ductility(5 °C) and quality; Weight average molecular weight of asphalt is the most significant factor influencing viscosity(135°C); Dispersion degree of asphalt is the most significant factor influencing elastic recovery. Conclusion provides the test basis for the evaluation of anti-aging properties of modified asphalt.

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