Use of micro Raman spectroscopy for the quantitative determination of polyethylene density using partial least‐squares calibration

A series of polyethylene samples were analysed using a micro Raman system. The data were analysed using a commercial partial least‐squares package and correlated with the polymer density. A correlation coefficient of up to 0.98 was obtained, depending on the spectral region used. A standard error of prediction of 2.15 kg m −3 was obtained and the densities of ‘blind’ samples were predicted with good accuracy.