Abstract: The repeatability and accuracy of density balance test of polyethylene resin density was investigated and compared with density gradient method. Both methods met the requirements in accuracy and precision of density determination. The difference between the two methods were ≤0.0005 g/cm3 for high density polyethylene and ≤0.0003 g/cm3 for low density polyethylene. As a result, the two methods could be used alternatively. The factors influencing the density balance method were also discussed.

Key words: density balance method, density, polyethylene resin, density gradient column method