Molekulasúlyeloszlás

Molekulasúlyeloszlás is a Hungarian term that translates to molecular weight distribution in English. It refers to the range of molecular weights present in a sample of a polymer or other macromolecule. Most synthetic polymers do not consist of molecules of a single, uniform size. Instead, they are a mixture of chains with varying lengths, and consequently, varying molecular weights. The molecular weight distribution provides a way to characterize this heterogeneity.

Key aspects of molecular weight distribution include the number-average molecular weight (Mn) and the weight-average molecular weight (Mw). Mn is the total weight of all molecules divided by the total number of molecules. Mw is calculated by summing the product of each molecular weight and its corresponding weight fraction. Typically, Mw is greater than Mn, and the ratio Mw/Mn is known as the polydispersity index (PDI). A PDI of 1 indicates a monodisperse sample (all molecules have the same molecular weight), which is rarely achieved for synthetic polymers. A higher PDI signifies a broader distribution of molecular weights.

The molecular weight distribution significantly influences the physical and mechanical properties of polymers, such as viscosity, solubility, tensile strength, and processability. Techniques like gel permeation chromatography (GPC), also known as size exclusion chromatography (SEC), are commonly used to determine the molecular weight distribution of polymers. Understanding and controlling this distribution is crucial for tailoring polymer properties for specific applications.