C-13 NMR-STUDY OF THE GRAFTING OF C-13 LABELED MALEIC-ANHYDRIDE ONTO PE, PP AND EPM

The chemical structure of polyolefins grafted with maleic anhydride (M A) has been the subject of much speculation, but thorough experimental studies are rare. MA with 99% C-13 in the double bond was synthesized and grafted onto PE, EPM and PP in the melt and solution. 1D INADEQUA TE C-13 NMR spectroscopy was used to characterize the products. Satura ted, monomeric MA graft structures are formed. Only for grafted PE sho rt MA oligomers are demonstrated. Grafting occurs on secondary and ter tiary carbons depending on the composition of the polyolefin. For PP a new, unsaturated MA graft structure on the polymer chain terminus is identified All graft structures are rationalized using a simple grafti ng mechanism.