3 years ago

Efficient Modulation of Polyethylene Microstructure by Proper Activation of (α-Diimine)Ni(II) Catalysts: Synthesis of Well-Performing Polyethylene Elastomers

Efficient Modulation of Polyethylene Microstructure by Proper Activation of (α-Diimine)Ni(II) Catalysts: Synthesis of Well-Performing Polyethylene Elastomers
Mario Maggio, Gaetano Guerra, Ilaria D’Auria, Claudio Pellecchia
The activation of a prototypical nickel(II) Brookhart catalyst by either methylalumoxane (MAO) or diethylaluminum chloride (AlEt2Cl) under a variety of conditions showed that a proper choice of the mode of activation is a powerful tool to modulate the polymer microstructure. In particular, use of AlEt2Cl instead of MAO resulted in the production of more branched polyethylenes with a higher content of long chain branches and even some “branches on branches”. Characterization of these materials by NMR, thermal, X-ray diffraction, and mechanical analyses provided insight into the relationships between the microstructure and the crystallization behavior and the elasticity of the polymers. For these branched polyethylenes, a transition from plastomeric toward elastomeric behavior occurs for branch concentrations much lower than for ethylene–propylene copolymers and like those observed for ethylene copolymers with bulkier comonomers. For elastomeric materials, reduction of branch concentration implies two relevant advantages: (i) reduction of glass transition temperature becoming closer to that of polyethylene; (ii) more efficient radical cross-linking with reduction of degradation reactions. An additional advantage is, of course, a polymer production process involving only ethylene.

Publisher URL: http://dx.doi.org/10.1021/acs.macromol.7b01214

DOI: 10.1021/acs.macromol.7b01214

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.