1 / 51.Size exclusion chromatography (SEC) is used to determine the molar mass distribution of polymers. SEC is not an absolute method. It requires calibration. Narrow molar mass fractions of atactic polystyrene are commonly used for calibration. The time for a given molecular species to flow through the column is dependent on the hydrodynamic volume of the molecule. It has been shown that the hydrodynamic volume is proportional to the product of the intrinsic viscosity [η ] and the molar mass M. The Mark-Houwink equation relates the two quantities according to:MK][where K and α are constants unique for a given combination of polymer, solvent and temperature. Derive the relationship between the molar masses of the polymer studied and of atactic polystyrene for a given eluation time. 解:At equal eluation time conditions the following expression holds: PSPSXXMM][][where X and PS are indices for the studied (X) polymer and polystyrene. Insertion of the Mark-Houwink equation yields: apsPSXPSaxXPSaPSPSPSXaxXXMKKMMMKMMK11which after taking logarithms and simplification gives: PSXPSXPSXXMaaKKaMlog11log11log2.It is well known that polyvinylchloride (PVC) is not miscible with its own monomer (VC). This gives the polymer a characteristic particle structure which remains even after melt-processing and leads to poor mechanical properties. The solubility parameters of PVC are: 2.18D, 5.7P, 3.8H, 5.3AOR(Barton 1983). The solubility parameter values of VC are: 4.15D, 1.8P, 4.2H. Confirm that PVC is immiscible with VC on the basis of these data. 2 / 5（2,,2,,2,,2)()()22(sHPHsPPPsDPDAR）解:Calculate first the distance between PVC and VC in three-dimensional solubility space;keep in mind that the dispersion values should be doubled:...
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