Grafting of unsaturated vinyl monomers onto polypropylene (PP) is a convenient route to develop new polymeric materials with synergistic properties. Particular attention must be paid to the formation of graft copolymer relative to the formation of homopolymer, since the final properties are dependent both on the dispersion of the new polymer into the iPP matrix, which is controlled by the degree of grafting, as well as on the chemical nature of the in-situ formed polymer chains. In the present work the grafting reaction of styrene on atactic PP (aPP), considered as good model system for the more studied solid-state modification of isotactic PP (iPP), has been investigated in the presence of two different radical initiators in order to get a first insight into the grafting reactions onto PP. Several grafting reactions were carried out by changing the chemical compositions of the starting polymerization mixture, whose homogeneity was accurately investigated by Raman spectroscopy. Infrared-spectroscopy (FT-IR) was used for qualitative and quantitative characterization of the reaction product. A quantitative separation procedure, based on the concept of selective solvent extraction, has been established which enables the determination of the grafting efficiency () as well as the exact chemical composition of the final product. Finally, all products were characterized by means of Differential Scanning Calorimetry (DSC) in order to study their thermal behaviour.
|Publication status||Published - 2001|