Raman mapping study of compatibilized and uncompatibilized polymer blends of Nylon 12 and polyethylene

Raman mapping images have been obtained for compatibilized and uncompatibilized polymer blends in films of Nylon 12 and high density polyethylene (HDPE) (blend ratios were 20/80, 50/50, and 80/20). A total of 400 Raman spectra were measured for each sample with areas of 100 mum(2) and in step sizes of 0.5 mum (for 20 X 20 probe spots). To develop the Raman mapping images, the intensity ratio of two bands, a band at 1635 cm(-1) due to Nylon 12 (amide I mode) and that at 1296 cm(-1) arising from both HDPE and Nylon 12 (CH2 twisting) is used. The Raman mapping images of the uncompatibilized polymer blends show a clear "sea-island" structure while those of the compatibilized polymer blends exhibit a compatibilized structure. The Raman mapping images enable simultaneous exploration of the morphology and molecular structure of the blends. We have also developed a Raman mapping image that represents the variation of crystallinity in the uncompatibilized film.