Synthesis
of a variety of optically transparent polyolefin elastomers
consisting of hard segment of polynorbornene and several kinds of
soft segments such as atactic polypropylene, poly(ethylene-co-propylene), and poly(ethylene-co-1-hexene)
was achieved. The block copolymers exhibited excellent toughness and
thermal property with efficient elastic recovery. Most importantly,
the introduction of hydroxyl group into polynorbornene segment not
only modulated surface property of block copolymers, but also improved
their mechanical properties.
A facile and efficient method to produce optically pure benzofuroindolines, especially those without 3-substituents that are susceptible to rearomatization, through [3+2] annulation of indoles with quinones is described. The suitable combination of a BOX ligand Cu hydrate complex and freshly activated molecular sieves functions to give controllably dynamic release of water, which enables the success of this reaction. This reaction can be performed on a gram scale with only 0.5 mol % catalyst loading.
Synthesis of hydroxy-functionalized cyclic olefin copolymer (COC) is achieved with remarkably high activity (up to 5.96 × 10 g-polymer mol-Ti h ) and controlled hydroxy group in a wide range (≈17.1 mol%) by using ansa-dimethylsilylene (fluorenyl)(amido)titanium complex. The catalyst also promotes living/controlled copolymerization to afford novel diblock copolymers consisting of hydroxy-functionalized COC and semicrystalline polyolefin sequence such as polyethylene and syndiotactic polypropylene, where the glass transition temperature of the norbornene/10-undecen-1-ol segment and each block length are controlled by comonomer composition and copolymerization time, respectively.
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