A RAMAN LAM STUDY OF LAMELLAR THICKNESS OF VIRGIN POLYETHYLENE POWDER

The lamellar thickness of polyethylene virgin reactor powder has been successfully measured using the Raman longitudinal acoustic mode (LAM). Relatively high lamellar thicknesses have been found. These values change with polymerization temperature in an unusual way, with lamellar thickness being larger for lower polymerization temperature, i.e., at higher undercooling for crystallization. Agreement within an experimental error of 10% has been obtained between values from LAM and those calculated by the Thompson-Gibbs equation from the melting point measured by differential scanning calorimetry.