The most effective polymer characterization technique for determining the molecular weight distribution of a polymeric material is Gel Permeation Chromatography GPC , also known as Size Exclusion Chromatography SEC . GPC/SEC is a widely used method for analyzing the molecular weight distribution of polymers because it provides a rapid and reliable measurement.The GPC/SEC technique works by separating polymer chains based on their hydrodynamic volume or size in solution. Here's a brief overview of how the process works:1. A sample of the polymer is dissolved in an appropriate solvent to create a polymer solution.2. The polymer solution is injected into a column packed with porous gel particles stationary phase . The column is typically filled with a solvent mobile phase that is compatible with the polymer.3. As the polymer solution flows through the column, the polymer chains interact with the porous gel particles. Smaller chains can penetrate deeper into the pores, while larger chains are excluded from the pores and remain in the mobile phase.4. Due to these interactions, larger polymer chains elute exit the column faster than smaller chains. This results in a separation of the polymer chains based on their size.5. A detector, usually a refractive index RI or ultraviolet UV detector, is placed at the end of the column to measure the concentration of the eluting polymer chains. The detector generates a chromatogram, which is a plot of detector response versus elution time or elution volume.6. The chromatogram is analyzed to determine the molecular weight distribution of the polymer. This is typically done by calibrating the GPC/SEC system with a series of polymer standards of known molecular weight and using their elution times to create a calibration curve. The molecular weights of the unknown polymer sample are then determined by comparing their elution times to the calibration curve.By using GPC/SEC, chemists can obtain valuable information about the molecular weight distribution of a polymeric material, which is crucial for understanding its properties and potential applications.