Investigation on terpolymer of ethylene/propylene/omega-bromo-alpha-olefins catalyzed by titanium complexes

摘要

Polyolefins with polar groups exhibited many applications as high-performance materials have been the subject of considerable research. In this study, terpolymers of omega-bromo-alpha-olefins with ethylene and propylene were synthesized in the presence of three multi-chelated non-metallocene titanium complexes. The structure and properties of the terpolymers were determined by H-1 NMR, C-13 NMR, Fourier transform infrared, differential scanning calorimetry after treatment by successive self-nucleating and annealing and wide-angle X-ray diffractograms. Furthermore, the stress-strain behaviors of the terpolymers were measured with ASTMD1708 microtensile, and the specimens were from the obtained terpolymer films. The results indicated that these catalysts were efficient for the terpolymerization. The catalytic activity was as high as 6.21 x 10(5) gP (molTi)(-1) h(-1) for terpolymerization of 11-bromo-1-undecylene with ethylene and propylene. The insertion ratio of 11-bromo-1-undecylene was up to 2.49 mol% confirmed by H-1 NMR and C-13 NMR. As for the terpolymers, their melting points decreased and their plasticity became weak with the incorporation of omega-bromo-alpha-olefins increasing. GPC results showed that the terpolymers had high weight-average molecular weight up to 2.51 x 10(5) g mol(-1). Molecular weight distribution of the terpolymers was about 2, implying single-site mechanism for the terpolymerization, but slightly broader than that of ethylene/propylene copolymer.