Heterophasic Polypropylene Copolymer Grafted with Itaconic Acid: Molecular Structure Analysis Through Fractionation Techniques

摘要

The functionalization of polypropylene (PP) through the grafting of unsaturated polar monomers such as maleic anhydride (MAH), acrylic acid and its derivatives, in the presence of organic peroxide as initiator, has received much attention over the past decades. However, up to now, only few studies have been reported on the effect of these polar monomers on crystallization and how they are distributed in the polymeric chain. In the present work heterophasic polypropylene copolymer was grafted with itaconic acid (AIt) using reactive extrusion. The main objective of this work was to evaluate the in?uence of itaconic acid in the rubber and crystalline phases in samples of PP. The separation of the different phases by xylene solubles analysis showed that the acid has preference to incorporate in the rubber fraction. The amount of itaconic acid was determinate by FTIR. It was concluded that the addition of peroxide and itaconic acid to the polymer causes changes of chemical and structural order in the generated material. The results showed a narrowing in the pro?le of crystallization of the samples analyzed by CRYSTAF resulting of a higher interaction between crystalline and amorphous phases, due to the presence of hydrogen bridges arising from the grafted acid.