منابع مشابه
Polymer Characterization: Polymer Molecular Weight Determination
Polymers are large molecules consisting of a large number of small component molecules chemically linked together. They are made from constituent monomers through polymerization process. Polymers are unique materials in that they consist of a statistical distribution of chains of varying lengths, and each chain consists of monomer residues which affect its properties hence they require several ...
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Alkyd resins were prepared into four different sets by varying the percentage concentrationof the glycerol content. Various properties such as the viscosity, Surface drying time, solubilityand color of the alkyd resins were evaluated for the various sets. The alkyd resin with the highestglycerol content was the most viscous, brownish in color and having the highest molecularweight this is due t...
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The applicability was investigated of automated spectrophotometric heparin assays and three clotting assays for determination of two low molecular weight (LMW) heparin fractions: Org 10172 and DxN10 and two infractionated commercially available heparins. The relative activity of the two commercially available heparins was similar in the anti-Xa assay, in the anti-IIa assay and in 3 clotting ass...
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-By using standard bromination conditions, the insoluble 1,2,1,2-polypropadiene (formed by Ni(acac)z or Co(acac)2 or 3, C3H,,, (iBu)3A1 catalysts) is transformed into a soluble bromopolypropadiene. Using this technique, determination of molecular weight becomes possible. It was found that the molecular weight increases with polymerization time until a steady value is reached. As the polymer yie...
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Supercritical fluid chromatography (SFC) has recently become a popular technique for the analysis of crude oils. It has been demonstrated for simulated distillation (1) and for hydrocarbon type separation (2-3). The advantages of SFC over gas chromatography (GC) in simulated distillation are the wider boiling range and lower temperature thus preventing cracking of heavy molecules during analysi...
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ژورنال
عنوان ژورنال: Nature
سال: 1977
ISSN: 0028-0836,1476-4687
DOI: 10.1038/269541a0