Morphological Raman analysis of short chain branched ethylene and propylene metallocenic copolymers

Abstract

Spectroscopic features in the Raman spectra of semicrystalline polyolefins that characterize different phase morphologies are reported. With growing incorporation of different 1-olefins, changes in the spectra due to different short chain branches are identified for polyethylene and polypropylene, both isotactic and syndiotactic. Bands were assigned to crystalline, semicrystalline and amorphous contents, and quantification was approached with the use of internal reference bands. The degree of crystallinity and the conformational order of the copolymers decrease with the increase in short chain branches content, and the behavior of larger short chains is different depending on the type of polymer analyzed. A semi ordered interphase was found, assigned and followed in all cases, as well as the evolution of amorphous phase with comonomer incorporation.