outrage
发表于 2025-3-28 15:52:06
Molecular Weight Averages and Distribution,is the sum of the weight times the MW of all the molecules divided by the total weight of the mixture as.The former corresponds to the number-average MW, .., and the latter is defined as the weight-average MW, M. There are five MW averages defined as the weight-average MW, ...
开花期女
发表于 2025-3-28 21:28:23
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apiary
发表于 2025-3-29 01:47:35
0945-6074and polymer/biopolymer characterization laboratories.There .Although size exclusion chromatography (SEC) is perhaps the most popular and widely used technique for determining the molecular weight distribution of polymeric materials, there have been very few texts written on this topic. During the p
外观
发表于 2025-3-29 04:43:36
Columns,ing materials, not only to the mobile phase but also to solutes, is one of the important factors for SEC. In order to maintain high-resolution separation, some of these packing materials are available only in the form of packed columns.
吸引力
发表于 2025-3-29 09:37:12
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flaggy
发表于 2025-3-29 12:34:03
Approaches to Molecular Weight Calibration,eries of narrow molecular weight distribution (MWD) standards of known MW and to relate the peak retention volume to the MW (peak position calibration curve). A sufficient number of narrow-MWD samples of the same polymer type, preferably 6 to 10 samples with different MW, are required as calibration standards.
monochromatic
发表于 2025-3-29 15:47:47
High-Temperature Size Exclusion Chromatography,ve 130 °C. Requirements for solvents used for high-temperature (HT) SEC are high boiling points, i.e. low volatility, good solubility for these polymers and a low viscosity at high temperature, in addition to good compatibility with the stationary phase.
防止
发表于 2025-3-29 22:31:15
Special Applications,ed according to the sizes of molecules in solution, not to their molecular weights. Therefore, determination of accurate values of MW averages and a molecular weight distribution (MWD) for a copolymer by SEC is limited to cases where the copolymer has a homogeneous composition across the whole range of molecular weights.
利用
发表于 2025-3-30 02:34:25
Introduction,f polymeric materials, as shown in Table 1.1. These properties govern polymer processing, end-use performance, and interactions with neighboring molecules. As compared to small molecules, which have a discrete and well-defined MW, most synthetic polymers are composed of hundreds to thousands of chai
向宇宙
发表于 2025-3-30 06:22:17
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