Functionalized amphiphilic polyethylene via direct copolymerizations of ethylene with α-olefin containing amino functionalization

Abstract

Transition metal-catalyzed copolymerization of olefins with polar monomers signifies a challenge because transition metal catalysts usually easily get poisoned by heteroatoms. Novel amino-containing polyethylene with high molecular weight, fluorescent functionality was synthesized by direct copolymerization of ethylene and amino-olefin containing shielding groups. The highly efficient non-metallocene catalyst system with high tolerance to polar monomers [N, P] complexes [silicon bridged diphenyl phosphorus-phenyl-amine multi chelated] can effectively promote the copolymerization of ethylene and amino-olefins containing considerable group protection, in which the catalysts very high catalytic activity (up to 6.56 × 10⁴ g mol⁻¹ h⁻¹) was achieved. The functional copolymer exhibited high molecular weight (up to 2.87 × 10⁵ g mol^–1) and amino-olefin comonomer incorporation (up to 2.43 mol%). Remarkably, the copolymer showed a high melting point (T_m around 138.7 °C) and thermal stability. The incorporated amino acid ester unit changes the surface characteristics of the polyolefin, making it have excellent hydrophilicity and fluorescence. Furthermore, as the content of functional copolymer increases, the properties both have significantly increased.

Graphical Abstract

Keywords:

• Amphiphilic functional polyethylene
• non-metallocene catalysts
• N-acetyl-O-(hex-5-enyl)-l-tyrosine ethyl ester
• fluorescence property
• hydrophilicity