Transmittance estimation of translucent polymeric pellets

Plastics are commonly produced and sold in pellet form due to their superior handling characteristics. However, due to their small size, it is often impractical, if not unfeasible, to determine the transmittance of a single pellet instrumentally. Moreover, such measurements may be highly variable. Therefore, translucent films of certain thickness, known as plaques, are commonly molded to enable instrumental determination of their transmittance. These plaques, however, are not needed beyond the quality control process while they add a costly step to the production process. In this study, we test a method, based on the layer theory, that enables the estimation of the transmittance spectra of nearly transparent plastic plaques from the reflectance measurements of their pellet counterparts. The comparison of the estimated transmittance spectra of pellets versus measured transmittance of plaques shows the RMSE ranging from 0.37%–1.80%, with a color difference, CIEDE2000(1:1:1), of 0.07–0.48, thus validating the applicability of the method.