Maleic anhydride modified ethylene-diene copolymers: Synthesis and properties

An ethylene/5,7-dimethylocta-1,6-diene copolymer was successfully modified with maleic anhydride (MAH) via the Lewis acid-catalyzed Alder Ene reaction. This work proposes a new approach to the functionalisation of polyethylene avoiding the use of peroxides. The effects of varying catalyst and MAH concentrations, temperature, time, as well as the presence of a free radical stabilizer were studied. FTIR data show the characteristic bands of succinyl anhydride rings grafted on the copolymer. Differential scanning calorimetry (DSC) was used to investigate the thermal properties of precursor and anhydride-grafted copolymers. The adhesion strengths of the copolymers in direct tension were also measured. Anhydride-grafted copolymers show a strong improvement of adhesion properties when compared to the ethylene/diene copolymer precursor or to the commercial polyethylene.