Study on the graft reaction of maleic anhydride onto metallocene-based polyethylene-octene elastomer

Grafting of maleic anhydride (MAH) onto metallocene based polyethylene - octene elastomer (POE) was studied in this article. By the results of Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and differential scanning calorimetry (DSC), it was confirmed that POE was grafted with MAH but the crosslinking reaction was accompanied by the predominant graft reaction due to a competition of POE macro-radical and excited MAH. Effects of various parameters such as monomer loading, initiator loading, and reaction time on grafting percentage and gel yield were also investigated. It was also found that the grafting percentage and the gel yield, at equilibrium, were both higher for POE containing lower degree of comonomer content. From the result of DSC characterization, it was shown that the change of crystallinity is slight for POE-g-MAH copolymer when the gel was removed from the copolymer. So one thought that the effect of gel formation on the properties of POE-g-MAH can be neglected due to the low gel yield. It was also proved that strength and elongation at break are both decreased while the grafting percentage was increased. Finally, the method proposed in this research can produce POE-g-MAH copolymer with low gel.