Structural Studies of Shrink-resist Polymers for Wool: The Influence of Molecular Weight and Functionality in Polypropylene Oxide Polyisocyanates

2008 ◽  
Vol 91 (10) ◽  
pp. 325-329 ◽  
Author(s):  
G. Bruce Guise ◽  
Michael A. Rushforth
Keyword(s):  
Molecular Weight ◽  
Structural Studies ◽  
Polypropylene Oxide

Structural studies of the capsular polysaccharide from Haemophilus pleuropneumoniae serotype 2

1987 ◽  
Vol 65 (5) ◽  
pp. 414-422 ◽  
Author(s):  
Eleonora Altman ◽  
Jean-Robert Brisson ◽  
Malcolm B. Perry
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
High Molecular Weight ◽  
Capsular Polysaccharide ◽  
Structural Studies ◽  
High Molecular Weight Polymer ◽  
Molecular Weight Polymer ◽  
Structure Formula ◽  
Nuclear Magnetic

The capsular polysaccharide of Haemophilus pleuropneumoniae serotype 2 (ATCC 27089) is composed of D-glucose (two parts), D-galactose (one part), glycerol (one part), and phosphate (one part). Hydrolysis, dephosphorylation, methylation, enzymic studies, and 1H and 13C nuclear magnetic resonance experiments showed that the polysaccharide is a high molecular weight polymer of a tetrasaccharide repeating units, linked by monophosphate diester and having the following structure:[Formula: see text]

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.

Molecular weight and structural studies on cephalopod rhodopsin

1979 ◽  
Vol 579 (1) ◽  
pp. 155-168 ◽  
Author(s):  
Kazuko Nashima ◽  
Masayasu Mitsudo ◽  
Yuji Kito
Keyword(s):  
Molecular Weight ◽  
Structural Studies

A probe for flagellar dynein in the mammalian mitotic apparatus

1981 ◽  
Vol 48 (1) ◽  
pp. 241-257
Author(s):  
G.W. Zieve ◽  
J.R. NcIntosh
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Indirect Immunofluorescence ◽  
Mitotic Spindle ◽  
Cultured Cells ◽  
Structural Studies ◽  
Mitotic Apparatus ◽  
Specific Staining ◽  
Bovine Sperm ◽  
Sperm Proteins

An anti-serum has been prepared in rabbits that precipitates high-molecular-weight bovine sperm proteins, including the dyneins. The activity of the serum against the dyneins is demonstrated by the recognition of dynein polypeptides in stained electrophoretic profiles of sperm proteins and in immunoprecipitates of radiolabelled sperm proteins. In addition, the serum stains the sperm flagella when used in indirect immunofluorescence and quantitatively inhibits the motility of demembranated sperm reactivated with ATP. However, the serum has additional anti-sperm activities besides those directed against the dyneins as demonstrated by the staining of the acrosome in indirect immunofluorescence. When used to immunoprecipitate proteins from extracts of cultured cells, the serum precipitates 2 polypeptides; one has a molecular weight higher than the flagellar dyneins, one lower. No specific staining of cultured cells is observed when an affinity-purified anti-dynein fraction IgG is used to stain a variety of cultured cells including bovine fibroblasts. We interpret these data to suggest that flagellar dynein is not a component of the mammalian mitotic spindle and discuss how this conclusion is consistent with recent genetic and structural studies on the mitotic spindle.

Polyethersulfone polymers and oligomers — Morphology and crystallization

2012 ◽  
Vol 90 (10) ◽  
pp. 880-890 ◽  
Author(s):  
Abdelkader Benhalima ◽  
François Hudon ◽  
Finda Koulibaly ◽  
Christian Tessier ◽  
Josée Brisson
Keyword(s):  
Molecular Weight ◽  
Model Compound ◽  
Crystal Form ◽  
Low Molecular Weight ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Crystal Forms ◽  
X Ray ◽  
Diphenyl Sulfone ◽  
Induced Crystallization

Crystal forms of polyethersulfones (PES) were investigated by using a model compound and a low molecular weight oligomer. These are amorphous as-synthesized, and can undergo solvent-induced crystallization under the appropriate conditions. The model compound, 4,4′-bis(p-methoxyphenoxy)diphenyl sulfone, yielded monocrystals, and its structure was solved using X-ray diffraction. Conformational disorder is present, two conformers cohabiting in 55:45 proportions. This model compound, combined to previous structural studies published in the literature, served as a basis for conformational studies of polyethersulfone. Low molecular weight polymers submitted to solvent-induced crystallization resulted in a PES crystal form different from that previously published in the literature, as shown by powder X-ray diffraction.

Preparation of a Certified Reference Material of Trifunctional Polypropylene Oxide

2011 ◽  
Vol 284-286 ◽  
pp. 1961-1968 ◽  
Author(s):  
Jing Xia Wang ◽  
Xiao Dong Fan ◽  
Wei Tian ◽  
Guang Wen Cheng ◽  
Juan Li Li
Keyword(s):  
Molecular Weight ◽  
Reference Material ◽  
Certified Reference Material ◽  
Storage Stability ◽  
Group Analysis ◽  
Size Exclusion ◽  
Distribution Model ◽  
Polypropylene Oxide ◽  
Exclusion Chromatography ◽  
End Group

Due to the lack of trifunctional polypropylene oxide (TPPO) certified reference material (CRM) with precise molecular weight on the market, it is therefore very important to prepare such CRM to calibrate the molecular weight testing equipments, and assure the quality in polyurethanes manufacture. In this paper, the certification of TPPO CRM was introduced based on the size-exclusion chromatography with a multi-angle laser light scattering (SEC-MALLS) method and end-group analysis method. First, TPPO was synthesized via controlled ring-opening polymerization of propylene oxide in the condition of both high temperature and pressure using double metal cyanide (DMC) complexes as catalyst, and TPPO oligomer as coinitiator. Then, the molecular weight homogeneity of TPPO CRM was evaluated by using the F-distribution model, and the storage stability of the molecular weight of TPPO CRM was assessed. All potential uncertainty factors for the certification of TPPO CRM were evaluated using cause-effect diagram. The results showed that the chemical structure of TPPO CRM was an anticipatory structure, which was confirmed by IR. The molecular weight homogeneity of TPPO CRM was qualified. The storage stability period of the final product was one year with respect to its molecular weight, and the certification results of TPPO CRM obtained by SEC-MALLS and end-group analysis were 4996±162 and 5025±146, respectively.

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