A combined Raman imaging and transmission electron microscopy study of blends of a deuterated linear polyethylene and a low-density polyethylene

Local compositional variations in blends are examined using micro-Raman ima ging. Raman images are compared with morphologies detected by transmission electron microscopy (TEM). In isothermally crystallized blends, with morpho logies composed of clusters of crystals rich in deuterated linear polyethyl ene (DLPE) in a matrix of quenched material, the results from both techniqu es are comparable. These results show that compositional variations of abou t 30% can be detected by Raman imaging on a scale as small as 2 mu m. In ra pidly quenched blends exhibiting morphological phase structures on a scale of 1-2 mu m in the electron microscope, the Raman images were homogeneous t o within the level of uncertainty in composition. However, the scale of the morphological phase structures examined is close to the limit of resolutio n of Raman imaging. It is shown that if there are compositional differences between the morphological phases, then these must be less than 3% in the s amples studied.