The synthesis and X-ray structure of a phenoxyimine catalyst tailored for living olefin polymerisation and the synthesis of ultra-high molecular weight polyethylene and atactic polypropylene

Fluorinated bis(phenoxy-imine)titanium complexes with methylaluminoxane for the synthesis of ultra high molecular weight polyethylene

“…1 H NMR spectroscopic analyses of all complexes reveal a single sharp peak of imine proton and three signals of aromatic protons suggesting that these complexes exist as the C 2 -symmetric isomer (see Supporting Information). In addition, according to previous report on the observed X-ray crystal structures of complex 3, it is reasonable to assume that complexes 1 and 2 have the same octahedral geometry with a trans-O, cis-N, and cis-Cl disposition in solution [29]. The optimized structures obtained from DFT calculations also support the proposed structures as shown in Fig.…”

“…All the complexes are active catalysts for ethylene polymerization and produce ultra high molecular weight polyethylene (UHMWPE) under the given conditions. The polyethylenes formed with these complexes exhibit the T m values in the range of 125.5e128.3 C. The constancy of the melting temperature with increasing polymerization temperature was also reported by Weiser and coworkers [29]. Plots of the catalytic activities of complexes 1e3 versus the polymerization temperatures are shown in Fig.…”

Research Progress of Pre - transition Metal Olefin Polymerization Catalyst for Salicylaldehyde Imine

“…This is because when the steric hindrance is large, the transition state of 6-membered ring structure is favors for the transfer of β-H to the monomer chain of ethylene, and promote the chain growth. When the steric hindrance is small, the transition state of 4-membered ring structure is not conducive to the growth of the polymer product chain [26]. The performance of the catalysts 38, 40, 41 was verifi ed to increase the polymerization activity of the catalytic system by increasing the steric hindrance of the phenoxy ortho substituents.…”

Zirconium complexes with versatile β-diketiminate ligands: Synthesis, structure, and ethylene polymerization

“…The production of UHMWPE probably resulted from the significantly faster chain propagation rate than b-hydride elimination or chain transfer reaction. These polymers could represent some of those possessing highest molecular weight encountered in homogenous olefin polymerization catalysts, including the group 4 metallocene catalysts [52][53][54][55].…”

“…For example, ultra-high molecular weight polyethylenes (UHMWPE) having a molecular weight (M w ) greater than 3 000 000 possess excellent abrasion resistance and impact strength, very low coefficient friction, good self-lubricants properties, as well as good resistance at low temperature [1][2][3][4][5][6][7][8]. Polyethylenes with broad or multi-model molecular weight distribution (MWD) can meet the requirement for good resin processability, since they show high workability due to the high molecular weight (HMW) fractions, and at the same time they provide excellent mechanical properties due to the low molecular weight (LMW) fractions [9,10].…”